Use of implantable pacemakers and implantable defibrillators in hypertrophic cardiomyopathy.
Recent data have emerged to help guide the use of implantable pacemakers and implantable defibrillators in patients who have hypertrophic cardiomyopathy (HCM). Controlled studies of the use of dual chamber pacemakers to treat outflow tract obstruction in HCM have shown little benefit, and have raised the possibility that earlier favorable reports were demonstrating an element of placebo effect. In particular, there is no recent support for earlier claims of regression of ventricular hypertrophy from chronic dual chamber pacing. Several reports have added to our understanding of the risk factors for sudden death in HCM. A normal blood pressure response to exercise appears to identify a subset of patients at low risk for sudden death. In a recent study of a large number of HCM patients, the risk of sudden death was found to be directly proportional to the extent of left ventricular hypertrophy. There is accumulating evidence that the implantable defibrillator is highly effective in terminating malignant ventricular arrhythmias in HCM patients, and HCM patients thought to be at significant risk for sudden death should be offered defibrillator implantation.
Freedman
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Arrhythmia Service, Cardiology Division, University of Utah Health Sciences Center, Salt Lake City, Utah, USA. roger.freedman@hsc.utah.edu
D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000517:prevention & control; D002304:Cardiac Pacing, Artificial; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D017147:Defibrillators, Implantable; D006801:Humans; D010138:Pacemaker, Artificial; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D016896:Treatment Outcome