Frequent ventricular premature contractions in heart failure: prevalence and prognosis

Premature ventricular contractions (PVCs) are extra heart beats arising from the ventricular, or pumping, chambers of the heart. Frequent PVCs are rare in the general population but more common in patients with congestive heart failure (CHF) who have poor heart function. Frequent PVCs may be further worsening heart function in these patients or interfering with other therapies for CHF. However, the impact of frequent PVCs on prognosis in the general CHF population has not previously been established. The objective of this project is to establish how common frequent PVCs are in the general CHF population and to assess whether frequent PVCs affect health outcomes in these patients. To do this, we propose to take advantage of existing data collected on a large CHF population as part of the Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (RAFT). This was a large, Canadian-designed, study of implanted device therapy in heart failure. The devices implanted in patients during this trial automatically recorded the amount of PVCs for each patient over the course of the study. This wealth of PVC information is available from electronic records collected as part of the RAFT study, but was not extracted in the initial study. Adding the PVC data to the original RAFT study data will allow us to examine of the impact of frequent PVCs in a large and contemporary CHF population. We anticipate that this study will demonstrate, for the first time, that frequent PVCs put CHF patients at higher risk of worsening heart function and death. Despite the advances over the last 30 years, CHF remains a disease with a poor prognosis and the treatment of CHF patients consumes a significant amount of health care resources. Effective therapies already exist for treating PVCs in patients with heart failure. Therefore, this study will provide the basis for evaluating whether PVCs are a new treatment target to improve the health and well-being of patients with CHF.