Single Beat ECG

Report:

Atrial flutter 180/min

Third degree AV block

Ventricular escape beat

Comment:

This looks like an agonal ECG, taken by inertia of the admission “workup” when the patient was already as good as dead. Not so: he was transferred to CCU, where he also averaged a beat per strip (Fig 55a) and – finally - paced. He survived to be discharged home.

Electrocardiographically, there are several questions, none of which can be answered (by me, at least) satisfactorily:

Is the rhythm an atrial tachycardia or flutter? Schamroth suggests 220/min as the cut-off, but admits there are overlaps on either side. Is the Ta (PT) elevation in the inferior leads a sign of atrial infarction, or part of a biphasic F wave, or innocuous repolarisation normal for this morphology and rate? Is the single QRS complex a ventricular escape beat, a junctional one with LBBB morphology, or a conducted LBBB complex? It looks like a VEB. The patient had LBBB at other times, but it looked different (in the same leads) from the beat recorded here. If conducted LBBB complex, what kind of AV block is this? It would sound decidedly weak to report this trace as “second degree AV block”. Most importantly, how did he survive? Medicine is a humbling profession.