Key Points
-HCM is the most common cause of sudden cardiac death in athletes
-In patient diagnosed with HCM, long-established guidelines have advocated against vigorous exercise with the assumption this decreases the risk of sudden death
-The findings of the LIVE-HCM trial, suggest that vigorous exercise is not associated with an increased risk of death, cardiac resuscitation, ICD shock, or cardiogenic syncope
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy and is associated with sudden cardiac death from ventricular arrhythmias. The prevalence of HCM in the United States is estimated to be as high as 0.29% or 1:344 individuals¹. In patients with HCM, the risk of vigorous exercise leading to sudden death is unknown. As a consequence, patients with HCM have historically been advised to avoid exercise, in particular sports, affecting quality of life and leading to sedentary lifestyles.
The results of this prospective, observational study (LIVE-HCM) evaluating vigorous exercise in patients with HCM compared to those with sedentary lifestyles were presented by Dr. Rachel J Lampert (Yale School of Medicine, New Haven, CT) at the ACC 2023 Conference today.
This trial enrolled 1,660 participants who were followed for three years. Participants had either a diagnosis of HCM and or had a genetic diagnosis without left ventricular hypertrophy (8%). Participants with NYHA class III or IV symptoms were among those excluded from the trial. The primary composite endpoint, adjudicated by a blinded committee, included death, resuscitated cardiac arrest, cardiac syncope, or appropriate ICD shock. Based on semi-annual surveys on physical activity, participants were grouped into vigorous exercise, moderate exercise, or sedentary. Vigorous exercise was defined as participating in an activity with 6 or greater metabolic equivalents for at least 60 hours a year. Moderate exercise was defined as 4-6 METs for over 60 hours per year, performing activities such as brisk walking or low-impact aerobics. Lastly, those not meeting the criteria for either moderate or vigorous exercise, were considered inactive.
Of the participants, 20% were under 25 years, 39% were female, 43% had ICDs, and 41% reported vigorous exercise. A total of 33 events occurred in the vigorous exercise group (n=699), compared to 44 events in the non-vigorous group (n=961). In total, 77 study participants experienced the study’s primary endpoint, a composite of total mortality, cardiac arrest, ventricular arrhythmia treated by an implanted cardio-defibrillator or fainting that was likely due to arrhythmia. All the events occurred in people who had overt HCM, and none occurred in people who carried a genetic variant but did not have left ventricular hypertrophy.
For the primary outcome, vigorous exercise as compared to non-vigorous exercise was not associated with an increased risk as measured by a cox-regression (HR 1.01, CI 0.68-1.48; p=0.98). Key limitations are that the participants self-selected for vigorous exercise, meaning there was no randomization, and participants were cared for in high-volume cardiology centers. Dr. Lampert points out that while “traditionally athletes have been restricted from exercise due to fears of sudden cardiac death,” emerging data supports young HCM patients engaging in sports when they receive appropriate cardiovascular care.
- Maron BJ, Mathenge R, Casey SA, Poliac LC, Longe TF. Clinical profile of hypertrophic cardiomyopathy identified de novo in rural communities. Journal of the American College of Cardiology. 1999;33:1590–1595.
