tag:blogger.com,1999:blog-3364570834099131201.post8762031246494527385..comments2024-03-19T03:19:40.572-04:00Comments on ECG Interpretation: ECG Blog #14 — The Cause of the Pause?ECG Interpretationhttp://www.blogger.com/profile/02309020028961384995noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-3364570834099131201.post-75788098389893726502022-08-29T19:32:40.647-04:002022-08-29T19:32:40.647-04:00@ Artek — Thank you for your question. The notchin...@ Artek — Thank you for your question. The notching on the T wave of beats #2 and #6 represents a “blocked” PAC — because no QRS complex occurs after these PACs. Therefore — we can presume that these PACs occur during the “absolute” refractory period.<br /><br />Of course — we do not know precisely where the absolute and relative refractory period lie — because that is an electrophysiologic concept … But in general — PACs that occur VERY early in the T wave are more likely to occur during the “absolute” refractory period (and therefore these early PACs are more likely to be non-conducted).ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.comtag:blogger.com,1999:blog-3364570834099131201.post-66822960832443308132022-08-26T07:03:13.296-04:002022-08-26T07:03:13.296-04:00Thank you for this great explanation, dr. Grauer.
...Thank you for this great explanation, dr. Grauer.<br /><br />I just wanted to clarify. Does "telltale" notching of T-wave in beat #2 represent PAC during absolute refractory period or during relative one? You mentioned that it corresponds to point B on figure 2. But how is it different from APC of beat #6 (which is conducted during absolute refractory period? If PAC during beat #2 were to conduct during RELATIVE refractory period, wouldn't it have widened QRS with aberrant morphology as you've mentioned before? Thank youArtekhttps://www.blogger.com/profile/09743195995275296465noreply@blogger.com