In the last of the Wenckebach case study series, Dr Harry Mond explores several ECGs with fascicular Wenckebach AV sequences with a reminder to always question the tracings!

In the first of a series on the electrocardiography of cardiac pacing, Assoc Prof Mond explores the fundamentals and everything you need to know about the stimulus artefact.

This Holter tracings showed a number of 2.8 second nocturnal pauses. A bundle branch block is also present. So the question was asked: Is this high degree AV block and does the patient need a pacemaker?

In this rare case, we see two very unusual and critical factors that together lead to atrial oversensing and “apparent” violation of the lower rate limit; a very narrow zone of open atrial sensing and far-field R wave sensing. While the first time MD Assoc Prof Harry Mond has seen this as atrial pacing, he explains how the issue can be very easily solved, reminding us, that normally there's no R wave sensing with AAI(R) pacing.

Dr Harry Mond explores the various arrhythmic events that can interrupt and terminate Wenckebach AV sequences including non-conducted atrial ectopics.

This week MD Assoc Prof H Mond examines the similarities between the characteristics of artefact vs non-atrioventricular Wenckebach blocks and the importance of recognising footprints for correct diagnosis.

Reported as dual chamber pacing, this case study needed closer examination. With obvious atrial pacing, the question of ventricular pacing remained. Assoc Prof Harry Mond details the characteristics that reveal the correct diagnosis, and why this should not be confused with pacemaker malfunction.

Handed this ECG, our Medical Director Assoc Prof Harry Mond was asked if it was an example of a rate adaptive pacing, which uses changes in transthoracic impedance to increase the pacemaker rate in response to physiologic demand. It was not a paced rhythm, however, these pacing algorithms create regular artefact on the ECG tracing, whether they are pacing or not in the ventricle. Using examples, we look at the technology and the defining characteristics that identify the correct results for each.

Often asked to review cardiac pacing ECGs, this one was presented as intermittent failure of ventricular capture. Revisiting atrial pacing and the tell-tale clues, we’re able to make the correct diagnosis.