AHRQ and the American College of Cardiology collaborate on study of implantable cardioverter defibrillators
Research Activities, March 2010, No. 355
A $3.5 million research project that will study the long-term benefits and risks of implantable cardioverter defibrillators (ICDs) in patients at risk of death from ventricular fibrillation will be supported by the Agency for Healthcare Research and Quality and the American College of Cardiology. The project is being conducted in cooperation with the National Heart, Lung, and Blood Institute, part of the National Institutes of Health.
Ventricular fibrillation is a dangerous type of abnormal heart rhythm that causes cardiac muscles in the ventricles in the heart to tremble rather than contract properly. The condition requires prompt attention. If the abnormal rhythm continues for more than a few seconds, blood circulation will cease, and sudden cardiac death may occur in minutes.
Patients at risk for ventricular fibrillation sometimes have ICDs implanted in their chests. These battery-powered devices, which are typically about 3 inches high and 2 inches wide, monitor the heart for abnormal heartbeats. If they detect potentially life-threatening rhythms, they deliver an electric shock to restore normal rhythm.
The new 3.5-year study will be conducted by members of the AHRQ-supported HMO Research Network, a consortium of 15 health care delivery systems that conduct research on various topics, including medical effectiveness and safety. The systems are also part of the National Heart, Lung, and Blood Institute's Cardiovascular Research Network. The results will also be helpful to the Centers for Medicare & Medicaid Services, which has covered ICDs for certain patients since 2005 and has required that certain Medicare patients receiving the devices be enrolled in a national registry.
The study will follow 3,500 patients with ICDs from the Cardiovascular Research Network to determine how often the devices deliver shocks, whether the shocks are appropriate, and to identify those patients who are most likely to require ICD shocks. AHRQ is providing $2.1 million to construct the study sample and collect ICD shock data within the first 2 years of the study. The American College of Cardiology Foundation is providing $1.4 million to collect and analyze shock data during the remainder of the study.