SVEBs in Bigeminy or 2:1 AV Block?

Report:

Sinus rhythm 72/min

Second degree AV block, 2:1

Ventriculophasic sinus arrhythmia

Left bundle branch block

Comment:

The ventriculophasic effect is so marked that one cannot be completely certain that the atrial complexes at the end of T waves are not ectopic P’ waves in non-conducted bigeminy. Their contour, insofar as can be made out, is identical to sinus P waves.

An hour later, the sinus rate and the AV block increased to 78/min and 3:1, respectively; there is more obvious respiratory sinus arrhythmia and the ventriculophasic sinus arrhythmia is less marked (Fig 422a). At 3:1 conduction ratio, the block can be called advanced or high-grade AV block. Its mechanism is still uncertain (two consecutive conducted P waves would be required to ascertain it), but it may well be a case of bilateral bundle branch block (BBBB).

The patient received a permanent pacemaker.

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