Atrial Sensing and Pacing

Report:

Sinus rhythm 75/min 1

VEB 1

Atrial-sensing ventricular pacemaker 3

Atrial sensing and pacing ventricular pacemaker (last beat) 4

Left atrial abnormality (LAA) 1

Comment:

This is a DDD pacemaker, responding to both the atrial activity and the lack thereof, after the VEB. The sinus P wave half-buried at the end of the VEB (its negative half best seen in the V1 rhythm strip) is ignored due to the ventricular depolarisation sensed immediately before – being within the PVARP9.

The VEB itself resembles the paced complexes in the four leads available (V4-6 and V1 strip). It may well have been pacemaker-induced. I remember hearing somewhere that any arrhythmia in the presence of an electronic pacemaker should be considered possibly caused by it. But what about a single VEB or, for that matter, two or three occurring singly? Common sense tells us to ignore them.

Below is the patient’s original trace, with 2:1 AV block and LBBB with primary T wave changes similar to those in Case 4 during paced rhythm. There is also a ventriculophasic sinus arrhythmia.