PR segment https://www.ecgguru.com/taxonomy/term/782/all en Sinus Tachycardia https://www.ecgguru.com/ecg/sinus-tachycardia-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/sinus-tachycardia-0"><img typeof="foaf:Image" src="https://www.ecgguru.com/sites/default/files/Sinus100.jpg" width="1800" height="1210" 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">This ECG is from a collection of tracings that, sadly, have no patient information.<span style="mso-spacerun: yes;">&nbsp; </span>It is interesting nonetheless, and we would love to hear your thoughts on it.</p><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;"><span style="color: #00b050;">ECG Findings:<span style="mso-spacerun: yes;">&nbsp; </span></span>The rhythm </strong>is sinus tachycardia, at a rate of 120 bpm.<span style="mso-spacerun: yes;">&nbsp; </span>The QRS is narrow at .08 seconds (82 ms).<span style="mso-spacerun: yes;">&nbsp; </span>While the <strong style="mso-bidi-font-weight: normal;">PR interval</strong> is normal, at .14 seconds (140 ms), the <strong style="mso-bidi-font-weight: normal;">PR segment</strong> is very short. The PR segment is the line between the end of the P wave to the beginning of the QRS complex.<span style="mso-spacerun: yes;">&nbsp; </span>This can indicate the presence of an accessory pathway that bypasses the AV node, or of faster conduction within the AV node. The P waves in the inferior leads II, III, and aVF barely meet voltage criteria for right atrial enlargement, <span style="mso-spacerun: yes;">&nbsp;</span>but the P waves in V1 do not have the usual prominent positive deflection one would expect with RAE.<span style="mso-spacerun: yes;">&nbsp; </span>Even with the short PR segment, the segment appears to be elevated in the inferior leads, without any reciprocal PR depression.<span style="mso-spacerun: yes;">&nbsp; </span>The PR segment is where atrial repolarization occurs (the atrial “T” wave). There are many conditions that can elevate or depress PR segments, and without a patient story here, we can’t guess at the cause.<span style="mso-spacerun: yes;">&nbsp; </span>If you are an instructor, this would be a good ECG to illustrate why we use the TP segment to determine the “isoelectric line”, rather than the PR segment.</p><p class="MsoNormal">The inferior <strong style="mso-bidi-font-weight: normal;">ST segments</strong> are very flat, which is not normal, while the rest of the ST segments display the normal concave up “smile” shape.<span style="mso-spacerun: yes;">&nbsp; </span>Serial ECGs would no doubt be helpful here, to recognize changes in the ST segments.</p><p class="MsoNormal"><strong style="mso-bidi-font-weight: normal;"><span style="color: #00b050;">Bottom Line</span></strong><span style="color: #00b050;">: </span><span style="mso-spacerun: yes;">&nbsp;</span>It would be much easier to make a determination about the causes of these subtle changes if we had patient information.<span style="mso-spacerun: yes;">&nbsp; </span>However, this ECG is still valuable as an exercise in measuring intervals, and as an example of short PR segment. It is also a good example of a fairly fast sinus tachycardia.<span style="mso-spacerun: yes;">&nbsp; </span>We would love to hear our visitors’ thoughts on this tracing.</p></div></div></div> Thu, 10 Oct 2019 02:42:23 +0000 Dawn 777 at https://www.ecgguru.com