Mahaim's bundle

Patient

26-year-old patient hospitalized for palpitations with sudden onset and termination; ECG recorded during the course of an episode;

Trace

Tachycardia of 180 bpm, left delay, left axis; atrial activity difficult to pinpoint (possible 1:1 ratio with atrial activity in the T wave);

Trace

The tachycardia is interrupted following vagal maneuvers; relatively short PR pattern with slightly pre-excited QRS;

Exergue

Initially, a bundle of Mahaim corresponded to fasciculo-ventricular or nodo-ventricular fibers; nowadays, the term "pseudo-Mahaim" is used in the context of atriofascicular or atrioventricular fibers with decremental conduction and the possibility of antidromic wide QRS tachycardias with a left delay pattern and left axis deviation;