Cardiology Associates of North Mississippi help discover a new therapy for Congestive Heart Failure patients
08/16/2004.
Cardiac resynchronization therapy (biventricular pacemakers) and implantable cardioverter defibrillators improve survival in patients with congestive heart failure, according to the results of the randomized Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) trial published in the May 20 issue of the New England Journal of Medicine.
In the COMPANION trial, 1,520 patients with advanced heart failure from ischemic or nonischemic cardiomyopathies were randomized in a 1:2:2 ratio to receive optimal pharmacologic therapy alone or in combination with cardiac resynchronization therapy with either a pacemaker or a pacemaker-ICD.
At baseline, patients were New York Heart Association (NYHA) class III or IV and had a QRS interval of at least 120 msec. Pharmacologic therapy included diuretics, ACE-inhibitors, beta-blockers, and/or spironolactone.
Compared with drug therapy alone, cardiac resynchronization therapy with a pacemaker decreased the risk of the primary composite end point, defined as the time to death from or hospitalization for any cause (hazard ratio, 0.81; P=.014). Cardiac resynchronization therapy with a pacemaker-ICD also decreased this risk (hazard ratio, 0.80; P=.01).
Compared with the pharmacologic-therapy group, the pacemaker group had a 34 percent reduction in risk of the combined end point of death from or hospitalization for heart failure (P < .002). Risk reduction compared with drug therapy alone was 40 percent in the pacemaker-ICD group (P < .001). A pacemaker reduced the risk of the secondary end point of death from any cause by 24 percent (P = .059), whereas a pacemaker-ICD reduced this risk by 36 percent (P = .003).
“In patients with symptomatic congestive heart failure and a bundle branch block on ECG, biventricular pacemaker implantation decreases the risk of death or first hospitalization and, when combined with an implantable defibrillator, significantly reduces mortality,” says Dr. Karl Crossen, principal investigator and electrophysiologist at Cardiology Associates of North Mississippi. “Patients with the pacemaker also experienced a reduction in hospitalizations and improved exercise tolerance and quality of life.” The decision for implantation of the pacemaker/ICD is best determined on an individual basis by patients and their physicians.
In an associated research study, Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) showed that ICDs reduced death by 23 percent in people with moderate heart failure compared to those who did not receive defibrillators. SCD-HeFT was a placebo-controlled, three-arm trial examining the use of ICD therapy and anti-arrhythmic drug therapy in patients who have moderate heart failure (New York Heart Association Class II or III), plus impaired pumping function of the left ventricle.
“The results of the trial show definitively that simple implantable defibrillator therapy will prolong life in patients with congestive heart failure,” said study director and principal investigator, Gust H. Bardy, M.D. “The study also shows that amiodarone, when used as a prophylactic medication, does not improve survival.”
Based on this data, all patients with moderate heart failure, with or without a history of coronary artery disease, should be evaluated for an ICD.”