I have spent thousands of hours (yes, thousands) looking at 12-lead ECG tracings, studying ECGs for the cardiology boards, interpreting ECGs for direct patient care, and developing ECG tutorials ...

Not all ECG tracings are clear cut and textbook quality. This ECG is a bit vague in a couple ways. There is some baseline artifact making it difficult to see if there is truly P wave activity.

Of course, such an approach requires more than a single ECG tracing. Incorporation of these ideas in one's "routine" is not cumbersome, necessary information derives from ubiquitously available ...

Figure 18B shows the 12-lead ECG of the entrainment tracing of Figure 18A. The QRS morphology in all 12-lead ECGs during entrainment is identical to that of pacing in the absence of tachycardia as ...