Resynchronization/Defibrillation for Ambulatory Heart Failure Trial

Cardiovascular mortality is decreasing in most industrial countries, however mortality for congestive heart failure is increasing. The most important predictors of mortality in heart failure patients are depressed left ventricular function, severity of symptoms (NYHA class), and ventricular conduction abnormality manifested as wide QRS. Recent advances in pharmacological therapy including ACE inhibitors, beta-blocker and spironolactone have resulted in improvement of symptoms and reduction in mortality. Population epidemiological studies demonstrated that mortality and hospitalization rate for heart failure remains very high despite recent pharmacological therapeutic progress. Recent short-term clinical trials demonstrated that cardiac resynchronization therapy (CRT) is effective in improving symptoms of heart failure, functional capacity and quality of life in patients with moderate to severe heart failure and conduction abnormality optimally treated with drug therapy. However, the data for morbidity and mortality in mild to moderate heart failure is lacking.

The objective of this trial is to determine if the addition of CRT to optimal pharmacological therapy and ICD is effect in reducing mortality and morbidity in patients with poor LV function, wide QRS and mild to moderate heart failure symptoms.

This is a double-blinded randomized control trial. A total of 1800 patients with mild to moderate heart failure symptoms, LVEF ≤ 30%, and QRS ≥ 120 ms will be included in the study. Patients will be randomized to either "ICD plus Optimal Medical Therapy (control)" or "CRT/ICD plus Optimal Medical Therapy (experimental)" in a 1:1 randomization ratio. Patients in the control group will be implanted with a single or dual chamber ICD. Patients in the experimental group will receive a device with the capabilities of CRT and ICD. Optimal Medical Therapy will include ACE inhibitors and beta-blockers. Patients will be followed on a regular basis and will have clinical evaluation, quality of life assessment, and six minute walk tests performed. The primary outcome is a composite of total mortality and heart failure hospitalization. Secondary outcome measures will include total mortality, cardiovascular mortality, sudden arrhythmic death, health related quality of life and cost economics. Patient accruement is scheduled for 4.5 years and a minimum follow of 18 months.

DFT sub study:

Overview of sub-study Design Patients participating in the RAFT trial, at participating sites, will be randomized to have DFT testing or no testing at the time of device implant. Up to 450 patients will be eligible for enrollment at Canadian and European centres. The study will have two primary outcomes: a short-term safety outcome and a long-term efficacy outcome. The safety outcome will be a composite of all adverse events potentially related to DFT that occur within 30 days following ICD implant. The long-term efficacy outcome will be a composite of failed first appropriate clinical ICD shock and sudden death. This pilot study is intended primarily to confirm the anticipated rates of events and to demonstrate feasibility of enrollment, but will not have statistical power to determine if intra-operative DFT testing is associated with significant short-term risk. If complication rates are as high as predicted and enrollment is feasible, then a larger study would be justified to determine the impact of intra-operative DFT testing on long-term rates of failed appropriated ICD shocks and sudden death. Events rates determined in this pilot study would then be used to estimate the sample size of this larger study.