title: Pacemaker-mediated tachycardias: an unresolved problem.
abstract: The advent of dual chamber pacing systems that restore atrioventricular synchrony and allow rate variability in response to physiologic stress has provided a major advance in pacing therapy. Undesirable pacemaker-mediated tachycardias may arise when the atrial sensing amplifier of a VDD or DDD device detects a retrogradely conducted P-wave, ectopic atrial tachycardia, myopectoral contractions, or environmental electromagnetic interference. The rate of the resultant tachycardia is determined by the programmed upper tracking rate of the pacemaker. Although seldom life-threatening, troublesome myocardial ischemia may ensue in patients with coronary artery disease. In most instances, the incidence and rate of pacemaker-mediated tachycardias may be minimized by judicious programming.
mesh_terms: D002304:Cardiac Pacing, Artificial / Q000379:methods; D004594:Electrophysiology; D006327:Heart Block / Q000628:therapy; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D013610:Tachycardia / Q000209:etiology* / Q000503:physiopathology