The Syncope ECG With Too Much P
ECG Weekly Workout with Dr. Amal Mattu
HPI
A 68-year-old man has syncope, then has a second syncopal episode while lying still on a stretcher during evaluation at an outpatient clinic. He is sent emergently to the ED. On arrival he remains lightheaded with borderline blood pressure and a ventricular rate in the low 50s. The arrival ECG shows electrocardiographic polyuria, or “too much P”, with more atrial activity than ventricular complexes.
Before watching this week’s workout, review the arrival ECG carefully and consider:
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- In an ECG with “too much P,” what are the four most important differential diagnoses you must consider before you commit to any specific label?
- What two quick observations can immediately eliminate two of the most dangerous possibilities within seconds?
- After you march out the P waves, what PR-interval pattern clinches the correct diagnosis and prevents you from making the wrong pacing decision?
