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Assoc Prof Harry Mond
February 23, 2026
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The techs this week showed me an atrial tachyarrhythmia which did not conduct to the ventricle. The rate was about 300 bpm and was slightly irregular. The pattern was repeated many many times.
Those, who report lots of Holters, see this about once a month and this is a focal atrial tachycardia with block, although the third beat probably conducts. This is rarely reported in the literature.In the next example from the same patient, there is again one conducted beat. The focal atrial tachycardia is irregular and the last atrial complex occurs earlier and then blocks. The ladder diagram, demonstrates that this is a “Wenckebach block at the ectopic-myocardial junction”.There is also a suggestion of Wenckebach AV block as well.
I reported this recently in Heart Lung and Circulation. The examples are below and a reprint enclosed.
Assoc Prof 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.
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?
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