study of exercise training in hypertrophic cardiomyopathy

Conditions: Cardiomyopathy, Hypertrophic

Summary: the investigators propose a pilot randomized controlled trial to determine the safety and potential benefits of moderate intensity exercise in patients with hypertrophic cardiomyopathy. the investigators hypotheses are that exercise parameters derived from a baseline cardiopulmonary exercise test will target an appropriately safe level of exercise intensity that will not cause significant arrhythmias or exacerbate symptoms and that exercise training for 4 months will result in significant improvements in peak oxygen consumption (peak vo2) and quality of life, with neutral effects on the clinical characteristics.

the goal of this randomized clinical pilot trial is to establish the safety profile and potential benefits of moderate intensity exercise in patients with hypertrophic cardiomyopathy (hcm). participation in competitive athletics is associated with an increased risk of sudden cardiac death (scd) in individuals with structural heart disease, including hcm. this has appropriately led to the establishment of national guidelines based on expert opinion that discourage participation in high intensity competitive sports, burst exertion (e.g., sprinting), or isometric exercise (e.g., heavy lifting). non-competitive, low to moderate intensity exercise is allowable, although many physicians and hcm patients are still understandably apprehensive. data on the safety of a recreational exercise program, and how to gauge appropriate intensity level, are desperately needed so that hcm patients can reap the well established health benefits of regular physical activity. limited, but compelling animal data suggest that moderate intensity exercise is not only safe, but may also prevent or even reverse cardiac hypertrophy, fibrosis, myocellular disarray, and apoptosis associated with hcm. there are no published studies on exercise in patients with hcm, although large clinical trials in heart failure have shown exercise training to be safe, to improve peak vo2 and quality of life, and to lower cardiovascular mortality. the pilot randomized control trial proposed here is the first to determine the safety of moderate intensity exercise training and explore its potential benefits in patients with hcm.

Eligibility criteria:
inclusion criteria: * age ≥ 18 years and ≤ 80. * diagnosis of hcm, defined by the presence of unexplained left-ventricular hypertrophy \> 13 mm in any wall segment. * agreement to be a participant in the study protocol and willing/able to return for follow-up. exclusion criteria: * history of exercise-induced syncope or arrhythmias (ventricular tachycardia or non-sustained ventricular tachycardia). * medically refractory left ventricular outflow tract obstruction being evaluated for septal reduction therapy. * less than 3 months post septal reduction therapy (surgery or catheter based intervention). * hypotensive response to exercise (\> 20 mm hg drop in systolic blood pressure from peak blood pressure to post exercise blood pressure). * pregnancy. * implantable cardioverter-defibrillator (icd) placement in last 3 months or scheduled. * left ventricular systolic dysfunction (left ventricular ejection fraction \< 55% by echocardiography). * worsening clinical status in the last 3 months, advanced heart failure (new york heart association class iv symptoms) or angina (canadian cardiovascular society class iv symptoms). * life expectancy less than 12 months. * inability to exercise due to orthopedic or other non-cardiovascular limitations. * unwillingness to refrain from competitive sports, burst activity, or heavy isometric exercise for the duration of the study.

Keywords: hypertrophic cardiomyopathy exercise oxygen consumption