Hypertrophic cardiomyopathy (HCM) is the most commonly encountered inherited cardiac condition in clinical practice, which was historically considered the leading cause of sudden cardiac death during exercise. Therefore, exercise recommendations for these patients were highly conservative and promoted a sedentary life style. Currently, there is emerging evidence suggesting that exercise in HCM has a favorable effect on cardiovascular remodeling, and moderate exercise programs in older HCM patients have improved their functional capacity without raising any safety concerns. However, younger patients are attracted to high intensity training (HIT) regimes.
On June 8, 2021, a randomized trial of HIT in younger HCM patients was presented at the British Cardiovascular Society 2021 Annual Conference. The study team enrolled 80 symptomatic and asymptomatic HCM patients aged 16–60 years who were stable on medication and able to exercise. They excluded competitive athletes and patients with any comorbidities that might interfere with them getting to high-intensity exercise.
After an initial assessment, the participants were randomised to either usual care or a 12-week exercise programme consisting of two sessions per week of alternating aerobic and resistance sessions. The baseline evaluations were then repeated at 12 weeks, and patients in the exercise group were encouraged to continue with the frequency and intensity of physical activity achieved at the end of the cardiac rehabilitation programme. The exercise arm was additionally followed up at 6 months, when baseline characteristics, physical activity levels, 48-hour Holter monitoring, cardiopulmonary exercise testing, and the questionnaires were again assessed.
The exercise programme was completed by 85% of participants, and adherence to the sessions was 75%.There was no difference between the exercise and usual care groups in the primary composite safety outcome of cardiovascular death, cardiac arrest, device therapy, exercise-induced syncope, sustained ventricular tachycardia, non-sustained ventricular tachycardia, and sustained atrial arrhythmias (p=0.99).
However, there was a significant increase in physical activity levels in the exercise group at 12 weeks (p<0.001), with patients increasing their total exercise time compared with controls (p=0.005).
The exercise group also had a significant increase in peak O2 versus controls, by an average of 3.7 ml/kg/min (p=0.006), oxygen uptake at anaerobic threshold, by 2.44 ml/kg/min (p=0.009), and time to anaerobic threshold, by 115s (p<0.001). Patients in the exercise group also saw significant improvements in systolic blood pressure, reducing by an average 7.3 mmHg versus controls (p=0.002), as well as body mass index, which reduced by an average of 0.8 mg/kg2 versus controls (p<0.001). Total cholesterol levels also decreased in the exercise group versus controls over the 12 weeks of the programme, by an average of 0.3 mmol/l (p=0.076). Finally, patients in the exercise group experienced improvements in anxiety (p<0.001) and depression scores (p=0.017) compared with those assigned to usual care.
