This protocol describes a randomized multicenter clinical trial designed to test the hypothesis that a 12-week program of high-intensity interval training (HIIT) yields larger beneficial effects in stable heart failure patients than current practice, defined as either a similar training program with the same volume of moderate continuous training (MCT) or a recommendation of regular exercise at moderate intensity at individual choice (RRE).

Evaluation criteria are left ventricular dimensions and function measured by echocardiography, aerobic capacity measured as peak oxygen uptake, quality of life, and the level of physical activity by questionnaires. Assessments will be made before and after the training program and at one year follow-up. Safety of HIIT will be assessed as incidence of adverse effects during the training program. Clinical events will be recorded as worsening of heart failure requiring intensified drug therapy (diuretics), ventricular arrhythmia, hospitalization due to cardiovascular disease, and all-cause mortality at one year follow-up. The core study has been initiated and endorsed by the European Association for Cardiovascular Prevention and Rehabilitation, Section for Basic and Translational Research, under the European Society of Cardiology, and allows for sub-studies involving one or more of the participating centers. Preliminary calculations suggest that a total number of 200 patients randomized 1:1:1 to the three intervention groups is needed to detect larger beneficial effects with HIIT with a p-value of 0.05 and statistical power of 0.90 (primary endpoint is reverse remodeling, assessed by comparison between groups of change in left ventricular end-diastolic dimension from baseline to 12 weeks).

Inclusion Criteria:

• Congestive heart failure after myocardial infarction or dilated cardiomyopathy with:

  • LVEF < 0.35,
  • NYHA class II - III,
  • Stable without any signs of worsening for at least 6 weeks,
  • Minimum 3 months of optimal medical treatment,
  • Previous revascularisation or CRT should be more than 6 months before inclusion.

Exclusion Criteria:

• Significant intercurrent illness last 6 weeks,
• Known severe ventricular arrhythmia with functional or prognostic significance unless protected with ICD,
• Significant ischemia,
• Hemodynamic deterioration or exercise-induced arrhythmia at baseline testing,
• Other heart disease that limits exercise tolerance (valve disease with significant hemodynamic consequences, hypertrophic cardiomyopathy etc.,
• Co-morbidity that may significantly influence one-year prognosis,
• Functional or mental disability that may limit exercise,
• Patients scheduled for heart transplant at time of inclusion,
• A habit of regular vigorous exercise or participation in a program of exercise training less than 6 months before inclusion, or participation in another clinical trial,
• Patients with COPD with FEV1 below 50% of expected values are excluded,
• Patients taking oral corticosteroids are excluded in all cases.