Endless loop tachycardia started by an atrial premature complex in a patient with a dual chamber pacemaker

• Published in: Journal of the American College of Cardiology Vol. 5; no. 3; pp. 707 - 710
• Main Authors: Frumin, Howard, Furman, Seymour
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.03.1985; Elsevier Science
• Subjects: Aged; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Cardiac Pacing, Artificial - adverse effects; Diagnosis, Differential; Electrocardiography; Emergency and intensive cardiocirculatory care. Cardiogenic shock. Coronary intensive care; Humans; Intensive care medicine; Male; Medical sciences; Pacemaker, Artificial - adverse effects; Pacemaker, Artificial - classification; Software; Tachycardia - diagnosis; Tachycardia - etiology; Tachycardia - physiopathology; Human; Atrium; Instrumental stimulation; Tachycardia; Arrhythmia; Right ventricle; Cardiovascular disease; Complication; Resuscitation; Ventricular extrasystole
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/S0735-1097(85)80398-3

In a patient with a dual chamber pacemaker that senses in both the atrium and ventricle (VDD, DDD), a ventricular depolarization temporally displaced from a P wave can cause retrograde atrial activation and initiate an endless loop pacemaker-mediated tachycardia. A case in which an endless loop tachycardia was initiated by an end-diastolic atrial premature complex is reviewed. Retrograde conduction occurred because of the change in the temporal relation of atrial sensing and atrioventricular (AV) node depolarization. The implanted pacemaker did not have the capability of atrial refractory programmability. Atrial refractory interval extension, which occurs in this model after a ventricular premature complex to protect against a retrograde P wave, was not invoked since the tachycardia was begun by an atrial rather than a ventricular premature complex. The tachycardia was controlled by shortening the programmable AV delay. The mechanism of tachycardia induction and its management are outlined. Atrial refractory programmability is required in all VDD or DDD pacemakers.