Defribrillator Improves Quality of Life in Heart Failure
But receiving shocks increases risk of death
WEDNESDAY, Sept. 3 (HealthDay News) -- Heart failure patients who receive an implantable cardioverter-defibrillator (ICD) have reduced mortality and report a good quality of life a year later compared with medical therapy, although patients who receive shocks also have a higher risk of death, according to two studies in the Sept. 4 issue of the New England Journal of Medicine.
In the first study, Daniel B. Mark, M.D., from Duke University Medical Center in Durham, N.C., and colleagues randomly assigned 2,521 patients with stable heart failure and reduced left ventricular function to state-of-the-art medical therapy plus amiodarone, amiodarone placebo, or an ICD. Compared with medical therapy alone (placebo), physiological well-being and other quality-of-life measures significantly improved in the ICD group at three and 12 months, but not at 30 months. ICD shocks in the month before assessment were linked to reduced quality of life. There were no significant differences in physical functioning, the report indicates.
In the second study, Jeanne E. Poole, M.D., from the University of Washington in Seattle, and colleagues examined long-term prognosis in 811 patients with heart failure who were implanted with an ICD. Over a median of 45.5 months, they found that 269 patients (33.2 percent) received at least one ICD shock: 128 received only appropriate shocks, 87 received only inappropriate shocks, and 54 received both types of shocks. Compared with no appropriate shock, an appropriate shock increased the risk of death from all causes (hazard ratio 5.68), while the same was true for an inappropriate shock compared with no inappropriate shock (hazard ratio 1.98), the report indicates.
"In summary, these two reports show that modern ICD therapy is prolonging survival in patients with heart failure, with relatively little compromise in the quality of life," Jeff Healey, M.D., and Stuart Connolly, M.D., of McMaster University in Hamilton, Ontario, Canada, write in an accompanying editorial. "It is somewhat disturbing to realize that actually receiving a shock is such an important predictor of death (commonly in association with progressive heart failure)."
The first study was partially supported by Medtronic, Wyeth-Ayerst Laboratories, and Knoll Pharmaceuticals. The second study was partially supported by Medtronic and Wyeth Pharmaceuticals. Authors from both studies and the editorial report financial relationships with the pharmaceutical industry.