Exercise Training in Hypertrophic Cardiomyopathy: (SAFE-HCM)

To explore the feasibility, safety, health and psychological benefits of a 12-week high intensity exercise programme in a young group of individuals with hypertrophic cardiomyopathy (HCM). This will pave the way for a large-scale randomised study of safety of exercise in HCM, the results of which will strengthen the evidence base for exercise recommendations.

A greater understanding of the pathogenic mechanisms underpinning HCM has translated to improved medical care and better survival of affected individuals. Historically these patients were considered to be at high risk of sudden cardiac death during exercise, therefore exercise recommendations were highly conservative and promoted a sedentary life style. There is emerging evidence which suggests that exercise in HCM has a favourable effect on cardiovascular remodelling and moderate exercise programmes have not raised any safety concerns. Furthermore, individuals with HCM have a similar burden of atherosclerotic risk factors as the general population in whom exercise has been associated with a reduction in myocardial infarction, stroke and heart failure, especially among those with a high-risk burden.

Small studies have revealed that athletes who choose to continue with regular competition do not demonstrate adverse outcomes when compared to those who discontinue sport, and active individuals implanted with an implantable cardioverter defibrillator (ICD) do not have an increased risk of appropriate shocks or other adverse events. The recently published exercise recommendations from the European Society of Cardiology account for more contemporary evidence and adopt a more liberal stance regarding competitive and high intensity sport in individuals with low-risk HCM.

However, further work is required into exercise prescription in younger non competitive individuals participating in higher intensity exercise. Moreover low/moderate intensity exercise may be appropriate for older HCM patients, it is unlikely to attract younger, often asymptomatic patients, who wish to engage in higher intensity regimes.Therefore this study aims to assess the feasibility, safety and outcomes of an individually tailored, high intensity exercise programme in young patients with HCM.

Eligibility Criteria:
Inclusion Criteria:

* HCM\*
* Age range (16-60 years)
* All genders
* All ethnicities
* Symptomatic and/or asymptomatic HCM patients (NYHA functional class I-II) stable on medication over the preceding 3 months
* Patients may have ICDs
* Patients able to exercise
* Patients able to commit to the full duration of the exercise programme
* Patients able to lie flat

Exclusion Criteria:

* Competitive athletes (individuals who participate in team or individual sports that require systematic training to participate in regular competition against others)
* Exercise induced syncope
* Uncontrolled ventricular arrhythmias (arrhythmias which cause distracting/disabling symptoms or have caused or may cause incapacity)
* NYHA class III-IV
* Severe LV failure (ejection fraction \<35%)
* Exercise limited by a non-cardiac (unrelated to HCM) cause
* Surgical myectomy
* Awaiting or recent device implantation (within the last 3 months if due to an arrhythmic events, 4 weeks for primary prevention)
* Known coronary artery disease - defined as a coronary artery lesion of \>50% on coronary angiography or known coronary intervention
* Renal failure (eGFR \<30ml/min, chronic kidney disease stage 4 and 5 or acute renal failure)
* Patients with Friedrich's ataxia, Noonan syndrome, Anderson-Fabry disease and other disorders associated with cardiac hypertrophy
* Pregnancy