ECG Guru - Instructor Resources - Incorrect machine interpretation https://www.ecgguru.com/ecg/incorrect-machine-interpretation en Long QT Syndrome,Look Closely and Do Not Trust the ECG-Computer https://www.ecgguru.com/blog/long-qt-syndromelook-closely-and-do-not-trust-ecg-computer <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/long-qt-syndromelook-closely-and-do-not-trust-ecg-computer"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/F15bZSaXsAM77DH.jpg" width="3686" height="1905" 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>ST-elevation V2/V3, why? The patient never had chest pain, echocardiography inconspicious. History of several syncopal episodes. But, there is something wrong with the ECG. We observe a sinus rhythm ECG, at first glance, there are ST-elevations in leads V2-V4. No ST-depressions are visible. Upon closer examination, a prominent T-wave is noted, starting immediately after the QRS complex. The ECG computer erroneously indicates a significantly shortened QT and QTc interval. Upon remeasurement, the QT interval should be around 500 ms, and thus the QTc interval around 510 ms, which is markedly prolonged. This is indicative of LQTS Type I, and the prominent T-wave may mimic cardiac ischemia. Never fully rely on the ECG computer's findings.</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/683/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 Long QT Syndrome,Look Closely and Do Not Trust the ECG-Computer 1/5</option><option value="40">Give Long QT Syndrome,Look Closely and Do Not Trust the ECG-Computer 2/5</option><option value="60">Give Long QT Syndrome,Look Closely and Do Not Trust the ECG-Computer 3/5</option><option value="80">Give Long QT Syndrome,Look Closely and Do Not Trust the ECG-Computer 4/5</option><option value="100">Give Long QT Syndrome,Look Closely and Do Not Trust the ECG-Computer 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-wOVTtfOlCTFLF6yyUJOI4sRlVd03zrpLLkKG_YBzqvk" /> <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%2Flong-qt-syndromelook-closely-and-do-not-trust-ecg-computer&amp;title=Long%20QT%20Syndrome%2CLook%20Closely%20and%20Do%20Not%20Trust%20the%20ECG-Computer"><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> Wed, 26 Jul 2023 12:36:37 +0000 Dr A Röschl 853 at https://www.ecgguru.com https://www.ecgguru.com/blog/long-qt-syndromelook-closely-and-do-not-trust-ecg-computer#comments Incorrect Machine Interpretation https://www.ecgguru.com/ecg/incorrect-machine-interpretation-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/incorrect-machine-interpretation-0"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/TP%20I00%20incorrect%20machine%20dx.jpg" width="3507" height="2550" 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 ECG is presented as an example of INCORRECT MACHINE INTERPRETATION.&nbsp; While there are many abnormalities in this ECG, it does <span style="text-decoration: underline;">not</span> represent a paced rhythm. While there are exceptions, most paced rhythms represent either AV sequential pacing, right ventricular pacing, or bi-ventricular pacing.</span></p><p class="MsoNormal"><strong><span style="font-size: 12.0pt; line-height: 107%;">RECOGNITION OF A PACED RHYTHM</span></strong></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">Recognizing a paced rhythm can be difficult in some cases. Because pacemakers now have so many programmable features, there is a wide variety of ECG changes associated with them.&nbsp; Pacer “spikes” can be difficult to see in all leads.&nbsp; Finding evidence of the device on the patient’s chest or via patient history is a big help in reminding us to scrutinize the ECG for paced rhythm.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">An </span><a href="https://www.ecgguru.com/ecg/av-sequential-pacing-ventricular-tachycardia"><span style="font-size: 12.0pt; line-height: 107%;">AV sequential pacemaker</span></a><span style="font-size: 12.0pt; line-height: 107%;"> or a </span><a href="https://www.ecgguru.com/ecg/paced-rhythm"><span style="font-size: 12.0pt; line-height: 107%;">right ventricular pacemaker</span></a><span style="font-size: 12.0pt; line-height: 107%;"> will pace the ventricles via the right ventricle.&nbsp; This produces a <strong>WIDE QRS </strong>and a leftward axis, often causing Leads II, III, and aVF to be negative and aVL and aVR to be positive.&nbsp; Along with the wide QRS, we will see <strong>DISCORDANT ST CHANGES. &nbsp;</strong>That is, there will be ST depression and T wave inversion in leads with positive QRS complexes and ST elevation and upright T waves in leads with negative QRS complexes.</span></p><p class="MsoNormal"><a href="https://www.ecgguru.com/blog/jasons-blog-ecg-challenge-week-sept-2-9"><span style="font-size: 12.0pt; line-height: 107%;">Bi-ventricular pacing</span></a><span style="font-size: 12.0pt; line-height: 107%;"> can be a little more complicated to recognize, as the QRS can be narrow, with signs of fusion between the wave produced by the LV electrode and the RV electrode.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The frontal plane axis is usually far right – aVR will be positive. &nbsp;Lead I will be negative.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The machine is wrong: &nbsp;there is no indication of a pacemaker, and P waves are present, even though they are not noted in the "PR Interval" or "P Axis".</span></p><p class="MsoNormal"><strong><span style="font-size: 12.0pt; line-height: 107%;">SO, THIS IS NOT A PACED RHYTHM – WHAT IS IT?</span></strong></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">There are many abnormalities in this ECG, and they can be due to many different conditions. All ECGs should be evaluated in a clinical setting, with the patient’s symptoms, signs, and medical history all considered.&nbsp; That being said, I will point out what I see to be abnormal, and await our readers’ and experts’ opinions.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The rhythm is sinus, at a rate of 62 bpm.&nbsp; The PR interval is not given by the machine, but P waves are very obvious, and the PR interval is about .24 seconds, a first-degree AV block.&nbsp; The QRS complex is measured by the machine as 114 ms wide (.11 seconds).&nbsp; This is barely under the 120 ms usually required for diagnosis of wide-complex rhythm, and many would consider it adequate for a wide QRS.&nbsp; If we accept that this is a wide-complex QRS, then we should look for the ECG criteria for </span><a href="https://www.ecgguru.com/ecg/instructors-collection-ecg-week-september-23-2015-right-bundle-branch-block-0"><span style="font-size: 12.0pt; line-height: 107%;">RIGHT BUNDLE BRANCH BLOCK</span></a><span style="font-size: 12.0pt; line-height: 107%;"> and &nbsp;</span><a href="https://www.ecgguru.com/ecg/left-bundle-branch-block"><span style="font-size: 12.0pt; line-height: 107%;">LEFT BUNDLE BRANCH BLOCK</span></a><span style="font-size: 12.0pt; line-height: 107%;">. In RBBB, there will be an rSR’ pattern in V1 and a small s wave in Leads I and V6.&nbsp; &nbsp;In LBBB, Leads I, V5 and V6 should have a broad, monomorphic, upright QRS.&nbsp; In this ECG, V5 and V6 have small s waves that contribute to the total width of the QRS, while the R waves are narrow in appearance. The term for a wide-complex, supraventricular rhythm that does not meet the criteria for either right or left BBB is INTRAVENTRICULAR CONDUCTION DELAY. (IVCD)</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The frontal plane axis is -17 degrees, which is normal, but slightly to the left.&nbsp; That would be typical of left bundle branch block.&nbsp; However, the pronounced S wave in Lead II and the deep S wave in Lead III are not typical.&nbsp; In </span><a href="http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC1017695&amp;blobtype=pdf"><span style="font-size: 12.0pt; line-height: 107%;">a study</span></a><span style="font-size: 12.0pt; line-height: 107%;"> of S waves in these two leads, they have been found to be very rare in healthy hearts, and often associated with M.I. and cardiomyopathy.&nbsp; The abnormal S waves studied were deeper than the R wave was tall, however. S waves can be seen in Leads II and III in ventricular conduction defects that cause wide QRS – like LBBB and IVCD .</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The ST segments and T waves in this ECG are clearly abnormal. T waves are inverted in Leads II, III, aVF; Lead I; Leads V4, V5, and V6; and they are biphasic in V3 as they transition from V2 (positive) to V4 (negative).&nbsp; The inverted T waves are very shallow in most leads, so it is hard to determine if they are symmetrical (indicating ischemia) or asymmetrical (with many causes).&nbsp;&nbsp; In cases of wide QRS, we expect to see DISCORDANT ST AND T WAVE CHANGES.&nbsp; That is, the ST and T waves will go opposite the main direction of the QRS.&nbsp; Right chest leads like V1 and V2, which have negative QRSs will have some ST elevation and upright T waves.&nbsp; The opposite is true over the left side, where we expect upright QRS complexes (I, aVL, V5, V6) and, in the case of wide QRS, depressed ST segments with inverted T waves.&nbsp; This is seen for the most part in this ECG, but Leads III and aVF seem to have CONCORDANT STs.&nbsp; It would be very helpful to know this patient’s current symptoms and recent medical history.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">There are also Q waves in V1 and V2 that meet the criteria for "pathological Q waves", a sign of necrosis. &nbsp;However, large Q waves (or more accurately, loss of initial R waves) are common in V1 and V2, and may not be related to acute M.I. &nbsp;This is where knowing the patient's presentation and history would be very helpful.&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">As stated, the MAIN REASON for posting this ECG is to show students, beginners and advanced alike, that the machine’s interpretation should be taken with a “grain of salt”, and the interpreter should never rely solely on that interpretation.&nbsp; But we must also make the point that every ECG should be interpreted, when possible, in the setting of the patient’s presentation. </span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">&nbsp;</span></p><p>&nbsp;</p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">&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/683/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 Incorrect Machine Interpretation 1/5</option><option value="40">Give Incorrect Machine Interpretation 2/5</option><option value="60">Give Incorrect Machine Interpretation 3/5</option><option value="80">Give Incorrect Machine Interpretation 4/5</option><option value="100">Give Incorrect Machine Interpretation 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-gvreOIewgP9FCRLVP7JI6fyQM9BQe3kFqp27tOfC7hU" /> <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/incorrect-machine-interpretation" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Incorrect machine interpretation</a></div><div class="field-item odd"><a href="/ecg/st-elevation" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">ST elevation</a></div><div class="field-item even"><a href="/ecg/st-depression" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">ST depression</a></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%2Fecg%2Fincorrect-machine-interpretation-0&amp;title=Incorrect%20Machine%20Interpretation"><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 Mar 2017 05:07:24 +0000 Dawn 726 at https://www.ecgguru.com https://www.ecgguru.com/ecg/incorrect-machine-interpretation-0#comments Complete AV Block With Junctional Escape Rhythm https://www.ecgguru.com/ecg/complete-av-block-junctional-escape-rhythm-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/complete-av-block-junctional-escape-rhythm-1"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/AVB117%20CHB%20Junct%20Esc.jpg" width="1800" height="1424" 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 ECG is from a 78-year-old woman.&nbsp; We do not know any clinical details.</span></p><p class="MsoNormal"><span style="font-size: 8.0pt; line-height: 107%;">&nbsp;</span><span style="font-size: 12pt;">We break from our usual habit of removing the ECG machine’s interpretation of the ECG to serve as a reminder that the computer interpretation can be wrong. </span><span style="font-size: 12pt;">&nbsp;</span><span style="font-size: 12pt;">ECGs should ALWAYS be interpreted by a knowledgeable person.</span><span style="font-size: 12pt;">&nbsp; </span><span style="font-size: 12pt;">The machine interpretation can serve as a reminder, but should not take the place of human interpretation.</span><span style="font-size: 8pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">Here is what we DO see:&nbsp; There is a normal sinus rhythm present, as evidenced by the regular P waves that do not change their morphology.&nbsp; Some of the P waves are “buried” behind QRS or T waves.&nbsp; The atrial rate is 95 bpm.</span><span style="font-size: 8pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The ventricular rhythm, at 40 bpm, is also regular, but is separate from the atrial rhythm.&nbsp; Even though some of the P waves LOOK like they have conducted to produce QRS complexes, they have not.&nbsp; The PRIs are not all the same.&nbsp; Neither do they “progressively prolong”.&nbsp; There is no irregularity of the QRS rhythm or variation in QRS morphology.&nbsp; We see the classic “AV DISSOCIATION” of complete heart block.</span><span style="font-size: 8pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">When there is a third-degree AV block with a narrow-QRS escape rhythm, we can assume the block is in the AV node.&nbsp; The junction is the escape focus, producing a narrow-complex rhythm between approximately 40-60 bpm.&nbsp; In this case, the QRS is slightly wide at 112 ms (.11 sec), and the QRS complexes in several leads are fragmented.&nbsp; Some might argue that there is an idioventricular escape mechanism.&nbsp; But, with a normal frontal plane axis, borderline width, &nbsp;and no T wave inversions, the rhythm looks more supraventricular.&nbsp; The R wave progresson on the precordial leads shows a persistently negative QRS with late transition in V5.&nbsp; The QRS complexes in V1 and V2 appear to have pathological Q waves.&nbsp; When R wave progression is not normal, we should also consider electrode misplacement.</span><span style="font-size: 8pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">The immediate concern for patients with AV dissociation and escape rhythms is the RATE.&nbsp;</span><span style="font-size: 12pt;">If the rate becomes very slow, it can have deleterious effects on the patient’s hemodynamic status.</span><span style="font-size: 12pt;">&nbsp; </span><span style="font-size: 12pt;">The rate can usually be quickly enhanced with the use of a pacemaker – either temporary trans-venous pacing or trans-cutaneous pacing.</span><span style="font-size: 8pt;">&nbsp;</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">Lastly, the ST segments over this entire ECG are flat and horizontal, a possible sign of ischemic disease.&nbsp; It is not localized to a specific part of the heart or coronary artery’s area.</span></p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">&nbsp;</span></p><p>&nbsp;</p><p class="MsoNormal"><span style="font-size: 12.0pt; line-height: 107%;">&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/683/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 Complete AV Block With Junctional Escape Rhythm 1/5</option><option value="40">Give Complete AV Block With Junctional Escape Rhythm 2/5</option><option value="60">Give Complete AV Block With Junctional Escape Rhythm 3/5</option><option value="80" selected="selected">Give Complete AV Block With Junctional Escape Rhythm 4/5</option><option value="100">Give Complete AV Block With Junctional Escape Rhythm 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 >5</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-4YClhFSzegBnI5SFzwj5Xf6HhFYdoujn9MrzCFV_QDM" /> <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/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/av-dissociation" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">AV dissociation</a></div><div class="field-item odd"><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 even"><a href="/ecg/incorrect-machine-interpretation" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Incorrect machine interpretation</a></div><div class="field-item odd"><a href="/ecg/junctional-escape-rhythm" typeof="skos:Concept" property="rdfs:label skos:prefLabel" datatype="">Junctional escape rhythm</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%2Fecg%2Fcomplete-av-block-junctional-escape-rhythm-1&amp;title=%20Complete%20AV%20Block%20With%20Junctional%20Escape%20Rhythm"><img src="/sites/all/modules/addtoany/images/share_save_256_24.png" width="256" height="24" alt="Share"/></a> </span> </span></li> </ul> Thu, 27 Oct 2016 20:29:42 +0000 Dawn 713 at https://www.ecgguru.com https://www.ecgguru.com/ecg/complete-av-block-junctional-escape-rhythm-1#comments