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Assoc Prof Harry Mond
December 2, 2024
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I was asked for an opinion on this ECG.

There is sequential shortening of the PR interval and no dropped beats.This is not AV dissociation or isorhythmic AV dissociation as the R to R intervals are different and related to the PR intervals.This is reversed Wenckebach and below is another example.

Reversed Wenckebach is a rare ECG finding where there is sequential shortening of the PR interval and when it reaches its shortest value, the sequence is repeated often without a dropped beat.When a dropped beat occurs, there may be syncope and a permanent pacemaker required.In the good old days this was an arrhythmia associated with digitalis toxicity.
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Dr Harry Mond
September 11, 2026
Fusion beats are an amalgam of two competing rhythms within the same chamber, atrial or ventricular. They are not “abnormal” beats and are a lesson in timing. For fusion beats to occur, two foci must commence propagation at or near the same time and both contribute to chamber depolarization. Both must be either atrial or ventricular and depending on the contribution of each, the resultant progeny have similarities to one or both parents.Â
August 26, 2026
Is this the impossible pacemaker ECG? It took me a while to work out what was going on. Is it pacemaker malfunction?‍ What do you think?
July 24, 2026
I came upon these ECG tracings of ventricular tachycardia from a Holter study in a 79-year old asymptomatic female. What do you think?