Project 170503

Heart failure (HF) affects 2% Canadians and is now the second leading cause of death. It is therefore important to identify potentially treatable factors that could improve the outcome of this disease. Obstructive and central sleep apnea (OSA and CSA, respectively) may be 2 such factors. They occur in approximately 50% of patients with heart failure (HF), where they increase the risk of premature death. Previous studies have shown that treating these 2 breathing disorders with continuous positive airway pressure (CPAP) improves heart function. However, owing to the small number of patients studied, and that CPAP is ineffective in alleviating CSA in many patients, these studies did not demonstrate that treating OSA or CSA reduces morbidity and mortality. Nevertheless, among HF patients with CSA, when CPAP did eliminate CSA, survival improved. Thus, there seems to be potential for treating OSA and CSA to improve survival in HF patients. Adaptive servo ventilation (ASV) is a new device that is equally effective in alleviating OSA, but more effective in alleviating CSA than CPAP. We therefore believe that this device has a greater chance to improve survival than CPAP. Accordingly, we will test the effects of ASV on death and hospitalization rates in 860 HF patients with OSA or CSA in 25 centres in Canada and 6 other countries. Positive results would fundamentally alter the way HF is investigated and treated.