Randomized Exploratory Study of Exercise Training in Hypertrophic Cardiomyopathy - RESET-HCM

Contribution To Literature:

The RESET-HCM trial indicates that moderate-intensity exercise training in patients with HCM improves exercise capacity without an increase in adverse events.

Description:

The goal of the trial was to assess the safety and efficacy of moderate-intensity exercise in patients with hypertrophic cardiomyopathy (HCM).

Study Design

Patients were randomly assigned in a 1:1 ratio to undergo either moderate-intensity exercise training for 16 weeks (n = 67) or to usual care (n = 69). Exercise consisted of a structured, home-based exercise program individually prescribed based on baseline heart rate reserve derived from baseline cardiopulmonary exercise test. The recommended modes were walking/jogging, swimming, cycling, and elliptical use.

  • Total number of enrollees: 136
  • Duration of follow-up: 16 weeks
  • Mean patient age: 50 years
  • Percentage female: 40%

Inclusion criteria:

  • HCM: presence of unexplained left ventricular (LV) hypertrophy ≥15 mm in any wall segment
  • 18-80 years old

Exclusion criteria:

  • History of exercise-associated ventricular arrhythmias/syncope
  • Hypotensive blood pressure (BP) response (>20 mm Hg drop in systolic BP) on prior exercise testing
  • Ejection fraction <55%
  • New York Heart Association class IV
  • Unwilling to refrain from competitive sports

Other salient features/characteristics:

  • Caucasian: 87%
  • HCM with resting obstruction: 17%
  • Prior septal reduction procedure: 26%
  • History of ventricular tachycardia, ventricular fibrillation, or aborted sudden cardiac death: 4%
  • Implantable cardioverter-defibrillator present: 34%
  • Beta-blockers: 67%

Principal Findings:

Primary endpoint was change in peak VO2 for exercise vs. usual care: 1.35 vs. 0.08 (mean difference 1.27, 95% confidence interval [CI] 0.17-2.37, p < 0.05).

Secondary outcomes for exercise vs. usual activity:

  • No changes in cardiac morphology, LV outflow tract gradients, or B-type natriuretic peptide (all p > 0.05)
  • Significant improvement in the physical functioning scale of Short Form-36 (between-group difference 8.2, 95% CI 2.6-13.7, p = 0.004).
  • Significant reduction in premature ventricular contraction (PVC) burden (between-group difference p = 0.04)
  • Nonsustained ventricular tachycardia: 31.7% vs. 23.1%
  • Syncope: 0% vs. 1.4%
  • Musculoskeletal injury: 4.5% vs. 4.3%

Interpretation:

The results of this pilot trial indicate that moderate-intensity exercise training in patients with HCM improves exercise capacity without an increase in adverse events such as syncope. There are also salutary effects on PVC burden and overall quality of life. These results are important since in clinical practice, patients with HCM are often discouraged from participating in physical activity. A larger trial with longer follow-up powered for safety endpoints may be necessary to inform guidelines, but this study does provide some reassurance for clinicians caring for HCM patients.

It should be noted that this trial enrolled only a few patients with high-risk features such as significant resting obstructive gradient, symptomatic HCM, or high burden of late gadolinium enhancement on magnetic resonance imaging. This study also does not address the suitability of HCM patients to participate in high-intensity and competitive sports.

References:

Saberi S, Wheeler M, Bragg-Gresham J, et al. Effect of Moderate-Intensity Exercise Training on Peak Oxygen Consumption in Patients With Hypertrophic Cardiomyopathy: A Randomized Clinical Trial. JAMA 2017;Mar 17:[Epub ahead of print].

Presented by Dr. Sara Saberi at the American College of Cardiology Annual Scientific Session (ACC 2017), Washington, DC, March 17, 2017.

Clinical Topics: Arrhythmias and Clinical EP, Diabetes and Cardiometabolic Disease, Heart Failure and Cardiomyopathies, Prevention, Sports and Exercise Cardiology, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Exercise, Sports & Exercise and ECG & Stress Testing

Keywords: ACC17, ACC Annual Scientific Session, Arrhythmias, Cardiac, Atrial Fibrillation, Cardiomyopathy, Hypertrophic, Cicatrix, Death, Sudden, Cardiac, Defibrillators, Implantable, Exercise, Exercise Test, Genetic Testing, Heart Failure, Hypertrophy, Mutation, Oxygen Consumption, Quality of Life, Sarcomeres, Sports, Syncope, Tachycardia, Ventricular


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