ECG Guru - Instructor Resources - Second-degree AV block Type II https://www.ecgguru.com/ecg/second-degree-av-block-type-ii en Second-degree AV Block with Left Bundle Branch Block & Lead Reversal https://www.ecgguru.com/blog/second-degree-av-block-left-bundle-branch-block-lead-reversal <div class="field field-name-field-blog-image field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/blog/second-degree-av-block-left-bundle-branch-block-lead-reversal"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/unnamed.jpg" width="3028" height="1899" alt="" /></a></div><div class="field-item odd"><a href="/blog/second-degree-av-block-left-bundle-branch-block-lead-reversal"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/Arm%20leads%20corrected.jpg" width="1800" height="1150" alt="" /></a></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p>This ECG shows second-degree AV block, Mobitz Type II and an interventricular conduction delay, probably left bundle branch block. The QRS width is about 130 ms, or .13 seconds. The first ECG was run with the right and left arm electrodes reversed, so we cannot demonstrate the usual criteria of LBBB:&nbsp; Wide QRS, Supraventricular rhythm, V1 negative deflection and Leads I and V6 with positive deflections.&nbsp; When the arm electrodes are reversed, Lead I becomes negative, Leads II and III switch places, and Leads aVL and aVR switch places.&nbsp; The second ECG demonstrates the arm electrodes in the correct position, and LBBB criteria met.&nbsp;</p> <p>In second-degree AVB, Type II, there is almost always ECG evidence of fascicular disease such as right bundle branch block or left bundle branch block, as Type II is most often an <strong>intermittent tri-fascicular block.&nbsp; </strong>That is, one or two fascicles of the bundle branches are completely blocked, and the remaining one or two fascicles are intermittently blocked.&nbsp; So, in this case, the left bundle branch (two fascicles) is blocked, and the right bundle branch (one fascicle) is intermittently blocked.&nbsp; At the moment all three fascicles are blocked, there is complete heart block.&nbsp; So, we could say that second-degree AVB, Type II is an <strong>intermittent trifascicular block</strong>, or <strong>intermittent complete AV block</strong>.</p> <p>&nbsp;</p> </div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/543/feed" method="post" id="fivestar-custom-widget" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--2" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 1/5</option><option value="40">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 2/5</option><option value="60">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 3/5</option><option value="80">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 4/5</option><option value="100">Give Second-degree AV Block with Left Bundle Branch Block &amp;amp; Lead Reversal 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="empty">No votes yet</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-_rllWLoZ7P2A1ne1WChmfrCfMVz2_xLlb9zF_P6war4" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_1"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fblog%2Fsecond-degree-av-block-left-bundle-branch-block-lead-reversal&amp;title=Second-degree%20AV%20Block%20with%20Left%20Bundle%20Branch%20Block%20%26%20Lead%20Reversal"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> <script type="text/javascript"> <!--//--><![CDATA[//><!-- if(window.da2a)da2a.script_load(); //--><!]]> </script></span></li> </ul> Sat, 27 May 2023 07:46:27 +0000 Dr A Röschl 843 at https://www.ecgguru.com https://www.ecgguru.com/blog/second-degree-av-block-left-bundle-branch-block-lead-reversal#comments Second degree AVB Mobitz Type II https://www.ecgguru.com/blog/second-degree-avb-mobitz-type-ii <div class="field field-name-field-blog-image field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/blog/second-degree-avb-mobitz-type-ii"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/Mobitz%20true_0.jpg" width="3679" height="1497" alt="" /></a></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p>This ECG is from an 80-year-old lady who has collapsed or had sycopal episodes several times. The ECG comes from a Holter monitor. She has arterial hypertension and coronary artery disease. The ECG shows a second-degree, Mobitz Type II AV block. In both types of AVB, the PP intervals are usually the same. In second-degree AVB, Type I, the PQ (or PR) intervals progressively prolong until a P wave fails to produce a QRS.&nbsp; The cycle repeats.&nbsp; In second-degree AVB, Type II, the PQ intervals stay the same.&nbsp; This is best identified by comparing the PQ intervals from just before the failed QRS and just after.&nbsp; In Type II AVB, those two PQ intervals must remain the same.</p> <p>&nbsp;</p> </div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/543/feed" method="post" id="fivestar-custom-widget--2" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--4" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Second degree AVB Mobitz Type II 1/5</option><option value="40">Give Second degree AVB Mobitz Type II 2/5</option><option value="60">Give Second degree AVB Mobitz Type II 3/5</option><option value="80">Give Second degree AVB Mobitz Type II 4/5</option><option value="100">Give Second degree AVB Mobitz Type II 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="empty">No votes yet</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--2" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-1f-uJuFjtUBx6JAMPQODaZMAPIVssAz-ZJaiccZcD2k" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_2"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fblog%2Fsecond-degree-avb-mobitz-type-ii&amp;title=Second%20degree%20AVB%20Mobitz%20Type%20II"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Sat, 27 May 2023 07:35:53 +0000 Dr A Röschl 842 at https://www.ecgguru.com https://www.ecgguru.com/blog/second-degree-avb-mobitz-type-ii#comments Ask The Expert https://www.ecgguru.com/expert-review/ask-expert-14 <div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p class="MsoNormal" style="margin-bottom: 0in; line-height: 15.0pt; background: white; vertical-align: baseline;"><span style="font-size: 9.0pt; font-family: 'Verdana',sans-serif; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; color: black; border: none windowtext 1.0pt; mso-border-alt: none windowtext 0in; padding: 0in; mso-no-proof: yes;"><span style="mso-spacerun: yes;"><span style="font-family: 'Lucida Sans Unicode', sans-serif;"><span style="font-size: 16px;"><strong>Today's Expert is Dr. Jerry Jones, MD, FACEP, FAAEM</strong></span></span><span style="font-family: Verdana, sans-serif;"><span style="font-size: 9pt;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </span></span></span></span></p><p class="MsoNormal" style="margin-bottom: 0in; line-height: 15.0pt; background: white; vertical-align: baseline;"><span style="font-size: 9.0pt; font-family: 'Verdana',sans-serif; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; color: black; border: none windowtext 1.0pt; mso-border-alt: none windowtext 0in; padding: 0in; mso-no-proof: yes;"><span style="mso-spacerun: yes;"><span style="font-family: Verdana, sans-serif;"><span style="font-size: 9pt;">&nbsp;J</span></span></span></span><span style="font-family: Verdana, sans-serif; font-size: 9pt;">erry W. Jones, MD FACEP FAAEM is a diplomate of the American Board of Emergency Medicine who has practiced internal medicine and emergency medicine for 35 years.&nbsp; &nbsp;&nbsp;<img src="/sites/default/files/pictures/Profile%20photo.jpg" width="96" height="100" style="float: right;" /></span></p><p class="MsoNormal" style="margin-bottom: 0in; line-height: 15.0pt; background: white; vertical-align: baseline;"><span style="font-family: Verdana, sans-serif; font-size: 9pt;">Dr. Jones has been on the teaching faculties of the University of Oklahoma and The University of Texas Medical Branch in Galveston. He is a published author who has also been featured in the New York Times and the Annals of Emergency Medicine for his work in the developing field of telemedicine. He is also a Fellow of the American College of Emergency Physicians and a Fellow of the American Academy of Emergency Medicine and, in addition, a member of the European Society of Emergency Medicine.&nbsp;</span></p><p class="MsoNormal" style="margin-bottom: 0in; line-height: normal; background: white; vertical-align: baseline;"><span style="font-size: 10.0pt; font-family: 'Verdana',sans-serif; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; color: black;">&nbsp;</span><span style="font-size: 9.0pt; font-family: 'Verdana',sans-serif; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; color: black; border: none windowtext 1.0pt; mso-border-alt: none windowtext 0in; padding: 0in;">Dr. Jones is the CEO of</span><span><a title="Medicus of Houston Website" href="http://www.medicusofhouston.com/"><span style="font-size: 9.0pt; font-family: 'inherit',serif; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; color: #0062a0; border: none windowtext 1.0pt; mso-border-alt: none windowtext 0in; padding: 0in;">&nbsp;Medicus of Houston</span></a></span><span style="font-size: 9.0pt; font-family: 'Verdana',sans-serif; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; color: black; border: none windowtext 1.0pt; mso-border-alt: none windowtext 0in; padding: 0in;">&nbsp;and the principal instructor for the&nbsp;</span><span><a href="https://medicusofhouston.com/"><span style="font-size: 9.0pt; font-family: 'Verdana',sans-serif; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; color: #0062a0; border: none windowtext 1.0pt; mso-border-alt: none windowtext 0in; padding: 0in;">Advanced ECG Interpretation Boot Camp and the Advanced Dysrhythmia Boot Camp</span></a></span><span style="font-size: 9.0pt; font-family: 'Verdana',sans-serif; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; color: black; border: none windowtext 1.0pt; mso-border-alt: none windowtext 0in; padding: 0in;">.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</span><span style="font-size: 9pt; font-family: Verdana, sans-serif;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</span></p><p class="MsoNormal" style="margin-bottom: 0in; line-height: normal; background: white; vertical-align: baseline;">&nbsp;</p><p class="MsoNormal"><strong><span style="font-size: 18.0pt; line-height: 107%; color: #00b050;">Question:</span></strong><span style="font-size: 20.0pt; line-height: 107%; color: #00b050;"><span style="mso-spacerun: yes;">&nbsp; </span></span><span style="font-size: 14.0pt; line-height: 107%; color: #00b050;">I teach beginner students. How can I explain the complex subject of “AV Blocks”? <span style="mso-spacerun: yes;">&nbsp;</span>I don’t want to teach incorrect information while trying to simplify the subject.</span></p><p class="MsoNormal" style="margin-bottom: 0in; line-height: normal; background: white; vertical-align: baseline;">&nbsp;</p><p class="MsoNormal"><strong><span style="font-size: 18.0pt; line-height: 107%; color: #00b050;">&nbsp;Answer:&nbsp; <a title="AV Blocks article" href="https://www.ecgguru.com/ecg-resource/av-blocks-dr-jerry-jones">AV Blocks Article By Dr. Jerry Jones&nbsp; (click link)</a></span></strong></p><p class="MsoNormal" style="margin-bottom: 0in; line-height: normal; background: white; vertical-align: baseline;"><a title="AV Blocks article" href="https://www.ecgguru.com/ecg-resource/av-blocks-dr-jerry-jones"><span style="font-size: 9.0pt; font-family: 'Verdana',sans-serif; mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman'; color: black; border: none windowtext 1.0pt; mso-border-alt: none windowtext 0in; padding: 0in;"><br /></span></a></p></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/av-blocks" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">AV blocks</a></div><div class="field-item odd"><a href="/ecg/atrio-ventricular-blocks" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Atrio-ventricular blocks</a></div><div class="field-item even"><a href="/ecg/first-degree-av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">First-degree AV block</a></div><div class="field-item odd"><a href="/ecg/second-degree-av-block-type-ii" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Second-degree AV block Type II</a></div><div class="field-item even"><a href="/ecg/third-degree-av-block-1" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Third-degree AV block</a></div><div class="field-item odd"><a href="/ecg/complete-av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Complete AV block</a></div><div class="field-item even"><a href="/ecg/conduction-system" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Conduction system</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_3"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fexpert-review%2Fask-expert-14&amp;title=Ask%20The%20Expert%20"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Sun, 20 Dec 2020 18:02:21 +0000 Dawn 795 at https://www.ecgguru.com https://www.ecgguru.com/expert-review/ask-expert-14#comments ECG Basics: Second-degree AV Block, Type II https://www.ecgguru.com/ecg/ecg-basics-second-degree-av-block-type-ii-0 <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/ecg-basics-second-degree-av-block-type-ii-0"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/167%20AVB%20Type%20II%203%20to%202.jpg" width="1398" height="279" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p>This rhythm strip was obtained from a man who was suffering an acute inferior wall M.I.&nbsp; There are ST elevation and hyperacute T waves.&nbsp; The rhythm is <strong>SINUS ARRHYTHMIA WITH SECOND-DEGREE AV BLOCK, TYPE II.&nbsp; &nbsp;</strong> There is also first-degree AV block.</p><p>There are more P waves than QRS complexes, with a 3:2 ratio.&nbsp; The atrial rate varies between 55 -68 beats per minute.&nbsp; The sinus rate speeds slightly after the dropped QRS in each group. The ventricular rate is about 40 bpm, with grouped beating. (Regularly irregular.)</p><p>The PR intervals are steady at 226 ms (slightly prolonged).</p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/543/feed" method="post" id="fivestar-custom-widget--3" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--6" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give ECG Basics: Second-degree AV Block, Type II 1/5</option><option value="40">Give ECG Basics: Second-degree AV Block, Type II 2/5</option><option value="60">Give ECG Basics: Second-degree AV Block, Type II 3/5</option><option value="80" selected="selected">Give ECG Basics: Second-degree AV Block, Type II 4/5</option><option value="100">Give ECG Basics: Second-degree AV Block, Type II 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >4</span></span> <span class="total-votes">(<span >3</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--3" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-H6Gw0HKlwxfMW9atE26nCQm5s5xcOLzZKsd8hA_sWAw" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/rhythm-strip" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Rhythm strip</a></div><div class="field-item odd"><a href="/ecg/first-degree-av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">First-degree AV block</a></div><div class="field-item even"><a href="/ecg/sinus-arrhythmia" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Sinus arrhythmia</a></div><div class="field-item odd"><a href="/ecg/basic-ecg" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Basic ECG</a></div><div class="field-item even"><a href="/ecg/ecg-basics" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">ECG Basics</a></div><div class="field-item odd"><a href="/ecg/second-degree-av-block-type-ii" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Second-degree AV block Type II</a></div><div class="field-item even"><a href="/ecg/av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">AV Block</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_4"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fecg-basics-second-degree-av-block-type-ii-0&amp;title=ECG%20Basics%3A%20%20Second-degree%20AV%20Block%2C%20Type%20II%20"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Tue, 08 Dec 2020 21:31:26 +0000 Dawn 794 at https://www.ecgguru.com https://www.ecgguru.com/ecg/ecg-basics-second-degree-av-block-type-ii-0#comments Second-degree AV Block, Type II https://www.ecgguru.com/ecg/second-degree-av-block-type-ii-1 <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/second-degree-av-block-type-ii-1"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/AVB122%20%202nd%20deg%20Type%20II%203%20to%201.jpg" width="1887" height="1454" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal"><strong><span style="color: #00b050;">The patient:</span></strong><span style="color: #00b050;"><span style="mso-spacerun: yes;">&nbsp; </span></span>Unfortunately, we no longer have information on this patient, other than the fact that she went to the OR for a permanent pacemaker implantation.</p><p class="MsoNormal"><strong><span style="color: #00b050;">The ECG:</span></strong><span style="color: #00b050;"><span style="mso-spacerun: yes;">&nbsp; </span></span>The atrial rate (P waves) is 99 beats per minute. The P waves are regular and all alike (NSR). The ventricular rate (QRS complexes) is 33 bpm, and the QRS complexes are regular and all alike. The PR intervals, when A-V conduction occurs, are 162 ms (.16 seconds) and all alike. The QRS complexes are wide, at 122 ms (.12 seconds). There is <strong>right bundle branch block</strong>, but no left hemiblock, as the frontal plane axis is normal. The QTc is prolonged at 549 ms.<span style="mso-spacerun: yes;">&nbsp; </span>Many ST segments on this ECG have a “flat” appearance, rather than the normal concave up shape.</p><p class="MsoNormal">The failure of 2 out of every 3 P waves to conduct indicates a <strong>second-degree AV block. </strong>Type I is a block of the AV node, with progressive prolongation of the PR interval until ONE P wave fails to conduct. Type II AV block is a block of the intraventricular conduction system. Clues that a second-degree AV block is Type II include:</p><p class="MsoListParagraphCxSpFirst" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->The PR intervals are all alike.</p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->More than one consecutive P wave is not conducted.</p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->A P wave that is NOT in the refractory period of the preceding beat is not conducted.</p><p class="MsoListParagraphCxSpLast" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->There is evidence of bundle branch (fascicular) block.</p><p class="MsoNormal">This is a <strong>second-degree AV block, Type II.</strong><span style="mso-spacerun: yes;">&nbsp; </span>Type II blocks are considered to be <em>intermittent tri-fascicular blocks.</em><span style="mso-spacerun: yes;">&nbsp; </span>That is, one or two of the three main fascicles are blocked, and the remaining one or two are intermittently blocked.<span style="mso-spacerun: yes;">&nbsp; </span>When conduction proceeds down the working fascicle(s), there is a QRS complex. When the intermittent block occurs, all three fascicles are blocked, producing a temporary complete heart block (trifascicular block).<span style="mso-spacerun: yes;">&nbsp; </span>In this example, it appears that the right bundle branch (one fascicle) is consistently blocked, and the left bundle branch (two fascicles) is intermittently blocked.</p><p class="MsoNormal">The most immediate concern for any patient with an AV block is <strong>rate</strong>. It is important to assess the patient’s perfusion status to determine if the rate is fast enough to maintain BP.<span style="mso-spacerun: yes;">&nbsp; </span>Type I AV blocks often respond to atropine, but Type II AV blocks do not, and it may even make them worse.<span style="mso-spacerun: yes;">&nbsp; </span>The safest approach is a <strong>temporary pacemaker</strong>, either transcutaneous or transvenous, to stabilize the patient. Type II AV blocks usually require a permanent implanted pacemaker, as they tend to worsen and lead to third-degree AV block with ventricular escape (rate &lt; 40 bpm) or ventricular standstill.</p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/543/feed" method="post" id="fivestar-custom-widget--4" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--8" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Second-degree AV Block, Type II 1/5</option><option value="40">Give Second-degree AV Block, Type II 2/5</option><option value="60">Give Second-degree AV Block, Type II 3/5</option><option value="80" selected="selected">Give Second-degree AV Block, Type II 4/5</option><option value="100">Give Second-degree AV Block, Type II 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3.1</span></span> <span class="total-votes">(<span >50</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--4" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-rhiwNATzeG9_9qolot_RShAMc7jhTUeAkgobv_2n5WQ" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/second-degree-av-block-type-ii" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Second-degree AV block Type II</a></div><div class="field-item odd"><a href="/ecg/right-bundle-branch-block-1" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Right bundle branch block</a></div><div class="field-item even"><a href="/ecg/av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">AV Block</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_5"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fsecond-degree-av-block-type-ii-1&amp;title=Second-degree%20AV%20Block%2C%20Type%20II%20"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Tue, 08 Dec 2020 19:47:50 +0000 Dawn 793 at https://www.ecgguru.com https://www.ecgguru.com/ecg/second-degree-av-block-type-ii-1#comments High-grade AV Block With Profound Bradycardia https://www.ecgguru.com/ecg/high-grade-av-block-profound-bradycardia <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/high-grade-av-block-profound-bradycardia"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/AVB120%20High%20grade%20w%20sinus%20brady.jpg" width="1800" height="768" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal">If you are an ECG instructor, you probably carefully choose ECGs to illustrate the topic you are teaching. One of the reasons for the existence of the ECG Guru website is our desire to provide lots of such illustrations for you to choose from.</p><p class="MsoNormal">Sometimes, though, an ECG does not clearly illustrate one specific dysrhythmia well, because the interpretation of the ECG depends on so many other factors.<span style="mso-spacerun: yes;">&nbsp; </span>In order to get it “right”, we would need to know information about the patient’s history, presentation, lab results, or previous ECGs. We might need to see the ECG done immediately before or after the one we are looking at.<span style="mso-spacerun: yes;">&nbsp; </span>Some ECG findings must ultimately be confirmed by an electrophysiology study before we can know for sure what is going on.</p><p class="MsoNormal">For those of us who are “ECG nerds”, it can be fun to debate our opinions and even more fun to hear from wiser, more advanced practitioners about their interpretations.</p><p class="MsoNormal">My belief, as a clinical instructor, is that we must teach strategies for treating the patient who has a “controversial” ECG that take into account the level of the practitioner, the care setting, and the patient’s hemodynamic status.<span style="mso-spacerun: yes;">&nbsp; </span>In some settings, it might be absolutely forbidden for a first-responder to cardiovert atrial fibrillation, for example.<span style="mso-spacerun: yes;">&nbsp; </span>But atrial fib is routinely cardioverted under controlled conditions in hospitals.<span style="mso-spacerun: yes;">&nbsp; </span>The general rule followed by emergency providers that “all wide-complex tachycardias are v tach until proven otherwise” has no doubt prevented deaths in situations where care providers did not agree on the origin of the tachycardia.</p><p class="MsoNormal"><strong><span style="color: #00b050;">The ECG: <span style="mso-spacerun: yes;">&nbsp;</span><span style="mso-spacerun: yes;">&nbsp;</span><span style="mso-spacerun: yes;">&nbsp;</span></span></strong>We do not have much patient information to go with this ECG, just that it is from a 71-year-old woman who developed severe hypotension and lost consciousness, but was revived with transcutaneous pacing.<span style="mso-spacerun: yes;">&nbsp;&nbsp; </span>Here is what we do know about this ECG:</p><p class="MsoListParagraphCxSpFirst" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->There are regular P waves, at a rate of about 39 bpm (sinus bradycardia).</p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->There are only two QRS complexes, shown in a total of six leads, and the rate is 13 bpm.</p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->The two PR intervals that are seen are the same at 368 ms, or .368 seconds (first-degree AVB).</p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->There are three P waves for every QRS complex. (second-degree AVB, Type II).</p><p class="MsoListParagraphCxSpMiddle" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->The QRS complexes are 144 ms wide (.14 seconds).</p><p class="MsoListParagraphCxSpLast" style="text-indent: -.25in; mso-list: l0 level1 lfo1;"><!--[if !supportLists]--><span style="font-family: Symbol; mso-fareast-font-family: Symbol; mso-bidi-font-family: Symbol;"><span style="mso-list: Ignore;">·<span style="font: 7.0pt 'Times New Roman';">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span></span><!--[endif]-->The QRS morphology cannot be evaluated in 12 leads here, but the pattern is consistent with right bundle branch block and left anterior fascicular block (bifascicular block).<span style="mso-spacerun: yes;">&nbsp; </span>Were we at the bedside, another 10 seconds of 12-lead ECG might produce a QRS that falls into the remaining leads’ sections of the tracing.</p><p class="MsoNormal">It would be very important to determine what caused the severe slowing of conduction. The paper speed has not been altered, and that should be ruled out whenever all rates and intervals are prolonged.<span style="mso-spacerun: yes;">&nbsp; </span>The severe sinus bradycardia, second-degree AVB, first-degree AVB, and bundle branch block all point to a global cause of poor conduction.<span style="mso-spacerun: yes;">&nbsp; </span>Electrolytes, drugs, vagal stimulation, possible acute M.I. – all of these need to be assessed.<span style="mso-spacerun: yes;">&nbsp; </span>And, eventually, the best definitive treatment will need to be decided.</p><p class="MsoNormal">But what is the <strong>MOST IMPORTANT </strong>issue here?<span style="mso-spacerun: yes;">&nbsp; </span><strong><span style="color: #c00000;">The RATE!</span></strong><span style="color: #c00000;"><span style="mso-spacerun: yes;">&nbsp; </span></span>And the patient’s response to the extremely slow rate.<span style="mso-spacerun: yes;">&nbsp; </span>Before we spend any time on the cause or treatment, we must address the rate and the patient’s hemodynamic status.<span style="mso-spacerun: yes;">&nbsp; </span>A transcutaneous pacemaker, if available, is called for.<span style="mso-spacerun: yes;">&nbsp; </span>CPR may be needed until the pacemaker can provide a perfusing rate. Rate-enhancing drugs may be used, and temporary transvenous pacing.<span style="mso-spacerun: yes;">&nbsp; </span>If the patient’s perfusion status is not addressed, the rest will not matter.</p><p class="MsoNormal">When students are taking an ECG class, they most often want to know, “what is the name of this rhythm?” and “what are some shortcuts or mnemonics I can use to remember the names of the rhythms?”.<span style="mso-spacerun: yes;">&nbsp; </span>They will be distressed if the instructor says, “This could be second-degree AVB, or we could call it high-grade AVB, or a longer strip might show it to be third-degree AVB.”<span style="mso-spacerun: yes;">&nbsp; </span>The instructor may even feel distressed by not knowing “for sure.”<span style="mso-spacerun: yes;">&nbsp; </span>But (and this is admittedly an editorial on my part), I think we do our students a disservice to lead them to believe that there is a “right” answer to every ECG strip. They need to know that some ECGs cannot and should not be read in a vacuum, but rather in light of the patient’s information. They need to know that comparison with a previous ECG, or adding additional leads, or running a longer strip may illuminate the problem.<span style="mso-spacerun: yes;">&nbsp; </span>But most of all, they should understand what immediate actions can safely be taken until we do “know for sure”.</p><p class="MsoNormal">We welcome your comments on this topic, whether you are a teacher, a student, a provider, or all of these.</p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/543/feed" method="post" id="fivestar-custom-widget--5" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--10" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give High-grade AV Block With Profound Bradycardia 1/5</option><option value="40">Give High-grade AV Block With Profound Bradycardia 2/5</option><option value="60">Give High-grade AV Block With Profound Bradycardia 3/5</option><option value="80" selected="selected">Give High-grade AV Block With Profound Bradycardia 4/5</option><option value="100">Give High-grade AV Block With Profound Bradycardia 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3.5</span></span> <span class="total-votes">(<span >27</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--5" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-gI2RpN-8u0Yq_G3TIBiVDTBxhjUR6Ch7gCfwOcHnsVY" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/high-grade-av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">High-grade AV Block</a></div><div class="field-item odd"><a href="/ecg/sinus-bradycardia" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Sinus bradycardia</a></div><div class="field-item even"><a href="/ecg/second-degree-av-block-type-ii" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Second-degree AV block Type II</a></div><div class="field-item odd"><a href="/ecg/right-bundle-branch-block-1" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Right bundle branch block</a></div><div class="field-item even"><a href="/ecg/left-anterior-fascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left anterior fascicular block</a></div><div class="field-item odd"><a href="/ecg/left-anterior-hemiblock" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left anterior hemiblock</a></div><div class="field-item even"><a href="/ecg/bifascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Bifascicular block</a></div><div class="field-item odd"><a href="/ecg/first-degree-av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">First-degree AV block</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_6"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fhigh-grade-av-block-profound-bradycardia&amp;title=High-grade%20AV%20Block%20With%20Profound%20Bradycardia"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Thu, 04 Jun 2020 20:24:18 +0000 Dawn 785 at https://www.ecgguru.com https://www.ecgguru.com/ecg/high-grade-av-block-profound-bradycardia#comments AV Block of Undetermined Type https://www.ecgguru.com/ecg/av-block-undetermined-type <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/av-block-undetermined-type"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/164%20High%20grade%20AVB.jpg" width="1800" height="265" alt="" /></a></div><div class="field-item odd"><a href="/ecg/av-block-undetermined-type"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/164%20High%20grade%20AVB%20Marked%20up.jpg" width="1800" height="265" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">This strip was obtained from a woman who presented to her doctor’s office with hypertension. While there is some artifact in the baseline, it is possible to determine the presence of P waves, thanks in part to having two leads to assess.&nbsp; We have provided an unmarked version of the strip for you to use, and also a marked version for the sake of this discussion.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;">The underlying rhythm</span><span style="font-size: 12pt; line-height: 107%;"> is sinus bradycardia, at about 60 bpm, but with some slight variation in the P to P intervals (about 920 ms to 1040 ms). Because of the artifact, it is difficult to determine the exact P to P intervals, and the exact morphology of the P waves. So, we can’t say for sure that the P waves are all alike.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;">The AV block </span><span style="font-size: 12.0pt; line-height: 107%;">occurs at a 3:1 ratio.&nbsp; That is, for every three P waves, one is conducted and produces a QRS complex.&nbsp; When the P waves are not conducted, an escape rhythm occurs.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; color: #00b050;">The escape rhythm </span><span style="font-size: 12.0pt; line-height: 107%;">occurs at an escape interval of about 1720 ms.&nbsp; In other words, when a QRS does not occur by that time, the escape beat is produced.&nbsp; It appears to be from the AV junction, in spite of the slow rate, because the escape QRSs look like the sinus conducted QRSs.&nbsp; Both sinus and junctional rhythms are conducted along the bundle branches and produce the same QRS morphology.&nbsp; The QRS complexes are approximately .08-.10 seconds wide.&nbsp; Note that QRS complexes numbered 3, 5, and 7 have a P wave fused to the beginning of the QRS, making the QRS look wide when it is not.&nbsp;&nbsp; A junctional escape rhythm results from AV block in the AV node, as the junction is the first available pacemaker below the AVN.</span><span style="font-size: 13.008px;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">This patient was scheduled for a treadmill stress test in her doctor’s office, which was cancelled. She had no cardiac symptoms at the time of the ECG, except the above-noted hypertension.&nbsp; Unexplained bradycardia, especially when accompanied by AV node blocks, should trigger an assessment for inferior wall M.I., since the inferior wall of the LV shares a blood supply with the SA and AV nodes in the majority of people.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">Whether an AV block is "second-degree" or "third-degree" may not matter as much as WHERE the block is and what the resulting rate is.&nbsp; If the block is in the AV node, as opposed to the bundle branches or lower His bundle, the patient will have the benefit of a junctional escape rather than a ventricular escape rhythm. AV node level blocks tend to be temporary and reversible, while sub-Hisian blocks can be more permanent and more life-threatening. The rate, and the cardiac output, matter more to the patient than the "degree".&nbsp; Should the rate be so slow that the patient loses perfusion, a pacemaker may be required to increase it.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;"> Our thanks to Palm Beach Gardens Fire Rescue for donating this strip.</span></p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/543/feed" method="post" id="fivestar-custom-widget--6" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--12" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give AV Block of Undetermined Type 1/5</option><option value="40">Give AV Block of Undetermined Type 2/5</option><option value="60" selected="selected">Give AV Block of Undetermined Type 3/5</option><option value="80">Give AV Block of Undetermined Type 4/5</option><option value="100">Give AV Block of Undetermined Type 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3</span></span> <span class="total-votes">(<span >7</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--6" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-73WsXfRvXAQ5LDorsPcrFcWC7vbrzYprJE2LNTv_Zx0" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/high-grade-av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">High-grade AV Block</a></div><div class="field-item odd"><a href="/ecg/second-degree-av-block-type-ii" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Second-degree AV block Type II</a></div><div class="field-item even"><a href="/ecg/escape-capture-bigeminy" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Escape-capture bigeminy</a></div><div class="field-item odd"><a href="/ecg/rhythm-strip" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Rhythm strip</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_7"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fav-block-undetermined-type&amp;title=AV%20Block%20of%20Undetermined%20Type"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Wed, 22 Nov 2017 22:48:37 +0000 Dawn 741 at https://www.ecgguru.com https://www.ecgguru.com/ecg/av-block-undetermined-type#comments Second-degree AV Block, Type II? https://www.ecgguru.com/ecg/second-degree-av-block-type-ii-0 <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/second-degree-av-block-type-ii-0"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/2nd%20deg%20Type%20II%203%20to%201.jpg" width="1887" height="1454" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">This ECG is taken from an elderly woman who complains of feeling weak and tired. We have no other clinical information, unfortunately.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">There is an obvious bradycardia, with more P waves than QRS complexes.&nbsp; Here is what we see:</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">*&nbsp; Atrial rate is around 115/min. and P waves are regular and all alike.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">*&nbsp; Ventricular rate is around 35/min. and QRS complexes are regular and all alike.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">*&nbsp; PR intervals, when they occur, are all the same at 162 ms.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">*&nbsp; QRS duration is wide at 122 ms.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">*&nbsp; QTc interval is prolonged at 549 ms. </span></p><p class="MsoNormal"><strong><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">What does this mean? &nbsp;</span></strong><span style="font-family: Arial, sans-serif; font-size: 12pt;">There is sinus tachycardia with second-degree AV block because the atrial rate is over 100/min, but not all P waves are conducted.</span><span style="font-family: Arial, sans-serif; font-size: 12pt;">&nbsp; </span><span style="font-family: Arial, sans-serif; font-size: 12pt;">The AV block looks like a Type II (Mobitz II) block because the PR intervals are all the same.</span><span style="font-family: Arial, sans-serif; font-size: 12pt;">&nbsp; </span><span style="font-family: Arial, sans-serif; font-size: 12pt;">This is a reliable indicator of conduction. (Not third-degree AVB). &nbsp;</span><span style="font-family: Arial, sans-serif; font-size: 12pt;">The wide QRS complexes are due to right bundle branch block.</span><span style="font-family: Arial, sans-serif; font-size: 12pt;">&nbsp; </span><span style="font-family: Arial, sans-serif; font-size: 12pt;">The ECG signs of RBBB are: 1) wide QRS; 2) supraventricular rhythm; and 3) rSR’ pattern in V1 and Rs, with a wide little s wave, in Leads I and V6.</span></p><p class="MsoNormal"><strong><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">Type II AV blocks</span></strong><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;"> are almost always blocks of the intraventricular conduction system.&nbsp; That is, they occur in the region of the bundle branches.&nbsp; A second-degree, Type II AVB is an “intermittent tri-fascicular block”.&nbsp; That is, one or two of the three main fascicles of the bundle branches is constantly blocked, and the remaining fascicle(s) is intermittently blocked.&nbsp; When all three fascicles are blocked, there is no QRS following the P wave. When the intermittently-blocked fascicle conducts, we see a QRS.&nbsp; Often, that QRS will be conducted with a bundle branch block pattern.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">In this case, there is a constant right bundle branch block.&nbsp; The left bundle branch appears to be intermittently blocked, resulting in no conduction for two beats.&nbsp; So, we would call this a 3:1 AV block. </span></p><p class="MsoNormal"><strong><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">What about the QTc interval?&nbsp;</span></strong><span style="font-family: Arial, sans-serif; font-size: 12pt;">The QT interval (corrected to a rate of 60) is 549 ms.</span><span style="font-family: Arial, sans-serif; font-size: 12pt;">&nbsp; </span><span style="font-family: Arial, sans-serif; font-size: 12pt;">This is prolonged in any age or gender. QTc intervals over 500 ms are associated with an increased risk of </span><a style="font-family: Arial, sans-serif; font-size: 12pt;" href="https://www.ecgguru.com/ecg/atrial-fib-cardiac-arrest/">Torsades de Pointes.</a><span style="font-size: 13.008px;">&nbsp;</span></p><p class="MsoNormal"><strong><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">Additional teaching points. </span></strong><span style="font-size: 12.0pt; line-height: 107%; font-family: 'Arial',sans-serif;">This is a great ECG to show students how P waves can “hide” in T waves.&nbsp; By carefully marching out the P waves, we can find the hidden ones, and also see how they affect the shapes of the T waves in each lead.&nbsp; V3 shows the P wave occurring on the upslope of the T wave. It is also a good case for discussion of treatment of bradycardias.&nbsp; At this rate, it is very likely that the patient is hemodynamically compromised.&nbsp; Generally, emergency transthoracic pacing is used until a temporary transvenous or permanent transvenous pacemaker can be applied. Patients with Type II blocks do not often respond well to atropine because the problem lies in the intraventricular conduction system. Atropine exerts it’s rate-increasing effect in the SA and AV nodes and by blocking the vagus nerve. Type II AV blocks are generally considered serious and prone to worsening.&nbsp; A complete heart block occurring at this anatomic level would have a ventricular escape rhythm rather than a junctional escape rhythm.&nbsp; AV blocks occurring at the level of the AV node, such as second-degree, Type I &nbsp;(Wenckebach) blocks, would be likely to have junctional escape. Prolonged QT intervals can be very serious, and the patient should be evaluated for reversible causes of the prolonged QT interval, while <a href="http://emedicine.medscape.com/article/157826-treatment#d15">medications known to prolong the QT interval</a> should be avoided.</span></p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/543/feed" method="post" id="fivestar-custom-widget--7" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--14" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Second-degree AV Block, Type II? 1/5</option><option value="40">Give Second-degree AV Block, Type II? 2/5</option><option value="60">Give Second-degree AV Block, Type II? 3/5</option><option value="80" selected="selected">Give Second-degree AV Block, Type II? 4/5</option><option value="100">Give Second-degree AV Block, Type II? 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >4</span></span> <span class="total-votes">(<span >4</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--7" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-5VxrFzOEZl5IrCfXavQV9nHRwrI0DM6paOa67MBIQHI" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/21-av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">2:1 AV block</a></div><div class="field-item odd"><a href="/ecg/high-grade-av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">High-grade AV Block</a></div><div class="field-item even"><a href="/ecg/second-degree-av-block-type-ii" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Second-degree AV block Type II</a></div><div class="field-item odd"><a href="/ecg/prolonged-qt-interval" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Prolonged QT interval</a></div><div class="field-item even"><a href="/ecg/av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">AV Block</a></div><div class="field-item odd"><a href="/ecg/right-bundle-branch-block-1" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Right bundle branch block</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_8"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fsecond-degree-av-block-type-ii-0&amp;title=Second-degree%20AV%20Block%2C%20Type%20II%3F"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Thu, 02 Feb 2017 05:09:56 +0000 Dawn 724 at https://www.ecgguru.com https://www.ecgguru.com/ecg/second-degree-av-block-type-ii-0#comments Left Bundle Branch Block With Second-Degree AV Block, Type II https://www.ecgguru.com/ecg/left-bundle-branch-block-second-degree-av-block-type-ii <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/left-bundle-branch-block-second-degree-av-block-type-ii"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/LBBB%20w%202nd%20deg%20Type%20II%20corrected.jpg" width="1583" height="1144" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal"><span style="font-family: Calibri, sans-serif; font-size: 14pt;">&nbsp;</span><span style="font-size: 12pt;">This ECG was obtained from an 84-year-old woman who was scheduled for surgery.</span><span style="font-size: 12pt;">&nbsp; </span><span style="font-size: 12pt;">When the anesthesiologist did this ECG, the surgery was cancelled. It is a very good example of fascicular-level blocks.</span><span style="font-size: 12pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The underlying rhythm is a regular sinus rhythm at about 95 bpm.&nbsp; There are some non-conducted P waves which are part of the sinus rhythm (not premature beats).&nbsp; When the P waves DO conduct, the PR interval is steady at about .15 seconds (148 ms).</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">In addition, there is a LEFT BUNDLE BRANCH BLOCK.&nbsp; The ECG criteria for LBBB are:&nbsp; 1) A supraventricular rhythm, 2) A wide QRS, and 3) A negative QRS in Lead V1 and a positive QRS in Leads I and V6.&nbsp; The QRS duration in this ECG is 136 ms.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">There are generally two fascicles (branches) in the left bundle branch, and one main fascicle in the right bundle branch.&nbsp; So, a LBBB represents a “bi-fascicular block”.&nbsp; That means that A-V conduction is proceeding down only one fascicle (the right bundle branch).&nbsp; In that fascicle, there is an “intermittent” block.&nbsp; When the RBB is not blocked, we see a QRS.&nbsp; When it is blocked, we see none.&nbsp; This is then termed an “intermittent tri-fascicular block” – otherwise known as SECOND-DEGREE AV BLOCK, TYPE II.&nbsp; Type II blocks nearly always have a wide QRS due to the underlying bundle branch pathology.&nbsp; You may see RBBB, LBBB, or RBBB with left anterior fascicular block (hemiblock).&nbsp; Very rarely, the combination might include left posterior hemiblock.&nbsp; The intermittent block in the “healthiest” fascicle(s) is what makes this a second-degree block, and not a complete heart block (third-degree AVB).</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The clinical implications of this block are that the heart is operating on only one fascicle, and that fascicle is showing obvious signs of distress.&nbsp; A third-degree AVB could be imminent.&nbsp; In addition, LBBB causes a wide QRS, which decreases cardiac output.&nbsp; Second-degree, Type II AVBs can result in very slow rates, and sometimes cause more hemodynamic instability that some third-degree AV blocks.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">This patient was scheduled for pacemaker implantation instead of the originally-scheduled surgery.&nbsp;</span></p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/543/feed" method="post" id="fivestar-custom-widget--8" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--16" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give Left Bundle Branch Block With Second-Degree AV Block, Type II 1/5</option><option value="40">Give Left Bundle Branch Block With Second-Degree AV Block, Type II 2/5</option><option value="60">Give Left Bundle Branch Block With Second-Degree AV Block, Type II 3/5</option><option value="80">Give Left Bundle Branch Block With Second-Degree AV Block, Type II 4/5</option><option value="100" selected="selected">Give Left Bundle Branch Block With Second-Degree AV Block, Type II 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >4.5</span></span> <span class="total-votes">(<span >4</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--8" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-POkgEDrxLnzAqlHRFClKtNQEItdRd9akK3OGvaw9Eb0" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">AV Block</a></div><div class="field-item odd"><a href="/ecg/left-bundle-branch-block-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left bundle branch block</a></div><div class="field-item even"><a href="/ecg/lbbb" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">LBBB</a></div><div class="field-item odd"><a href="/ecg/intermittent-trifascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Intermittent trifascicular block</a></div><div class="field-item even"><a href="/ecg/bifascicular-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Bifascicular block</a></div><div class="field-item odd"><a href="/ecg/second-degree-av-block-type-ii" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Second-degree AV block Type II</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_9"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fleft-bundle-branch-block-second-degree-av-block-type-ii&amp;title=Left%20Bundle%20Branch%20Block%20With%20Second-Degree%20AV%20Block%2C%20Type%20II"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Tue, 29 Nov 2016 00:44:52 +0000 Dawn 717 at https://www.ecgguru.com https://www.ecgguru.com/ecg/left-bundle-branch-block-second-degree-av-block-type-ii#comments AV Block With Changing PR Intervals https://www.ecgguru.com/ecg/av-block-changing-pr-intervals <div class="field field-name-field-ecg field-type-image field-label-hidden"><div class="field-items"><div class="field-item even"><a href="/ecg/av-block-changing-pr-intervals"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/Type%20II%20second%20deg%20with%20dual%20AV%20pathways.jpg" width="1800" height="708" alt="" /></a></div></div></div><div class="field field-name-field-ecg-interpretation field-type-text-long field-label-hidden"><div class="field-items"><div class="field-item even"><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">Just like other subjects we are taught in school, ECG interpretation is usually taught in a very basic, simplistic way.&nbsp; As we add to our knowledge, we are able to determine the mechanisms of more complex rhythms.</span><span style="font-size: 12pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">When I took my first basic ECG rhythm monitoring course, I memorized all the “rules”, and at the end of the course, I thought I could read ANY strip correctly.&nbsp; Then, in real life, I found that some rhythms can’t be interpreted from one lead, or even from one 12-lead ECG.</span><span style="font-size: 12pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">This strip offers advanced readers to challenge themselves, and it offers teachers a chance to show students an “exception to the rules” if it is appropriate for those students.&nbsp; We all learn the classification of second-degree AV blocks:&nbsp; Both Type I and Type II show an underlying sinus rhythm with some P waves conducted and some not.&nbsp; Type I has progressively prolonging PR intervals until a P wave is non-conducted.&nbsp; The cycle restarts after the dropped QRS.&nbsp; Type II has PR intervals that are all the same, and may be prolonged or normal.</span><span style="font-size: 12pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">In this ECG, you will be able to “march out” a normal sinus rhythm at a rate of 80 bpm.&nbsp; The P waves are marked with small dots at the bottom.&nbsp; Two of every three P waves are followed by QRS complexes.&nbsp; Is it Type I?&nbsp; No – the PR intervals are not prolonging.&nbsp; Is it Type II?&nbsp; The PR intervals are not the same!&nbsp; What is happening?</span><span style="font-size: 12pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">There is also left bundle branch block, which is a sub-Hisian block.&nbsp; Blocks occurring in the intraventricular conduction system include bundle branch blocks, second-degree AVB Type II,&nbsp; and third-degree AVB with ventricular escape.&nbsp; This group of blocks tends to be more threatening than the blocks that occur in the AV node (second-degree type I and third-degree with junctional escape).</span><span style="font-size: 12pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">In this strip, you will notice that the first conducted P wave in each group conducts with a PRI of about .34 seconds (340 ms).&nbsp; The second PRI in each group conducts with a PRI of about .24 seconds (240 ms).&nbsp; They are decreasing before the non-conducted beat.&nbsp; There are several possible explanations for the change in PRI.&nbsp; One is </span><a href="http://content.onlinejacc.org/article.aspx?articleid=1121671"><span style="font-size: 12.0pt; line-height: 107%;">PRI alternans</span></a><span style="font-size: 12.0pt; line-height: 107%;">, due to conduction alternating through two AV pathways, one fast, one slow.&nbsp; Another is </span><a href="https://www.ncbi.nlm.nih.gov/m/pubmed/8269303/"><span style="font-size: 12.0pt; line-height: 107%;">supernormal conduction</span></a><span style="font-size: 12.0pt; line-height: 107%;">.</span><span style="font-size: 12pt;">&nbsp;</span></p><p>&nbsp;</p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">We would be very interested to hear what our readers think of this interesting ECG. For beginner students – don’t be scared off by complex mechanisms.&nbsp; To the patient, the bottom line is RATE.&nbsp; Initial treatment should be aimed at maintaining a workable rate and adequate perfusion.&nbsp; The actual mechanism of the dysrhythmia may need to be determined later by experts, and it may require evaluation in the electrophysiology lab for a firm diagnosis.&nbsp;</span></p></div></div></div><div class="field field-name-field-rate-this-content field-type-fivestar field-label-above"><div class="field-label">Rate this content:&nbsp;</div><div class="field-items"><div class="field-item even"><form class="fivestar-widget" action="/taxonomy/term/543/feed" method="post" id="fivestar-custom-widget--9" accept-charset="UTF-8"><div><div class="clearfix fivestar-average-text fivestar-average-stars fivestar-form-item fivestar-hearts"><div class="form-item form-type-fivestar form-item-vote"> <div class="form-item form-type-select form-item-vote"> <select id="edit-vote--18" name="vote" class="form-select"><option value="-">Select rating</option><option value="20">Give AV Block With Changing PR Intervals 1/5</option><option value="40">Give AV Block With Changing PR Intervals 2/5</option><option value="60">Give AV Block With Changing PR Intervals 3/5</option><option value="80" selected="selected">Give AV Block With Changing PR Intervals 4/5</option><option value="100">Give AV Block With Changing PR Intervals 5/5</option></select> <div class="description"><div class="fivestar-summary fivestar-summary-average-count"><span class="average-rating">Average: <span >3.6</span></span> <span class="total-votes">(<span >9</span> votes)</span></div></div> </div> </div> </div><input class="fivestar-submit form-submit" type="submit" id="edit-fivestar-submit--9" name="op" value="Rate" /><input type="hidden" name="form_build_id" value="form-KhREHvnQEkM2oIU4DPlSSpCQNd8OSIMBJHwf1fRAsq8" /> <input type="hidden" name="form_id" value="fivestar_custom_widget" /> </div></form></div></div></div><div class="field field-name-field-taxonomy field-type-taxonomy-term-reference field-label-above"><div class="field-label">Related Terms:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/ecg/second-degree-av-block-type-ii" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Second-degree AV block Type II</a></div><div class="field-item odd"><a href="/ecg/pr-alternans" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">PR alternans</a></div><div class="field-item even"><a href="/ecg/concealed-conduction" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Concealed conduction</a></div><div class="field-item odd"><a href="/ecg/dual-av-conduction-pathways" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Dual AV conduction pathways</a></div><div class="field-item even"><a href="/ecg/av-block" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">AV Block</a></div><div class="field-item odd"><a href="/ecg/supernormal-conduction" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Supernormal conduction</a></div><div class="field-item even"><a href="/ecg/left-bundle-branch-block-0" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Left bundle branch block</a></div></div></div><ul class="links inline"><li class="addtoany first last"><span><span class="a2a_kit a2a_target addtoany_list" id="da2a_10"> <a class="a2a_dd addtoany_share_save" href="https://www.addtoany.com/share#url=https%3A%2F%2Fwww.ecgguru.com%2Fecg%2Fav-block-changing-pr-intervals&amp;title=%20AV%20Block%20With%20Changing%20PR%20Intervals"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Thu, 29 Sep 2016 03:23:59 +0000 Dawn 711 at https://www.ecgguru.com https://www.ecgguru.com/ecg/av-block-changing-pr-intervals#comments