title: Pacemaker-mediated tachycardia initiated by coincident P-wave undersensing and ventricular blanking period.
abstract: Pacemaker-mediated tachycardias (PMT) have received much recent attention. We describe the course and treatment of a 60-year-old man with an AV universal (DDD) pacemaker who developed a pacemaker-mediated tachycardia. The tachycardia was initiated by the coincidence of an unsensed P-wave, a QRS that was also not sensed due to the ventricular blanking period, and a short right ventricular myocardial effective refractory period. Treatment consisted of reprogramming the atrial sensitivity of the device. Physicians should be aware of the potential for the ventricular blanking period to participate in the initiation of pacemaker mediated tachycardias.
authors.forename: G A
authors.initials: GA
authors.lastname: Lamas
authors.forename: E M
authors.initials: EM
authors.lastname: Antman
mesh_terms: D001145:Arrhythmias, Cardiac / Q000628:therapy*; D004562:Electrocardiography; D006323:Heart Arrest / Q000503:physiopathology / Q000628:therapy*; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D013610:Tachycardia / Q000503:physiopathology*