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Patient
79-year-old man implanted with a Medtronic dual-chamber pacemaker for complete atrioventricular block; 3 days after discharge, consultation in the emergency room for palpitations; recording of this tracing; programming in DDD mode;
Trace
Wide QRS tachycardia; a careful analysis of the tracing allows demonstrating a small-amplitude pacing artifact from V3 to V5; ventricular pacing; different hypotheses may be considered: supraventricular arrhythmia followed at the maximum rate, pacemaker-mediated tachycardia, sinus tachycardia; atrial activity is difficult to identify in order to refine the diagnosis;
Trace
EGM analysis confirms the diagnosis of pacemaker-mediated tachycardia: uninterrupted succession of VP-AS cycles (ventricular pacing, atrial sensing) with automatic prolongation of the AV delay so as not to exceed the maximum follow-up rate;
Exergue
The electrocardiographic diagnosis of pacemaker-mediated tachycardia is based on the demonstration of a tachycardia with ventricular pacing (wide QRS with pacing artifact) and retrograde atrial conduction (negative P' waves in the inferior leads). This diagnosis can sometimes be difficult (artifacts and P' waves difficult to identify) but should be systematically evoked in the presence of a regular tachycardia with wide QRS in an implanted patient.
Pacemaker-mediated tachycardia (PMT) is the term used to define pacemaker-driven tachycardia, most often at the maximal pacing rate with repeated ventricular pacing - retrograde atrial conduction sequences.