CMAJ: CRT+medical or defibrillator therapy can reduce mortality

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Adding cardiac resynchronization therapy (CRT) to optimal medical therapy (OMT) or defibrillator therapy reduces mortality in heart failure patients, according a meta-analysis published in the Jan. 31 issue of the Canadian Medical Association Journal.

“Cardiac resynchronization therapy has been shown to reduce morbidity and, when compared with medical therapy alone, to reduce mortality,” the authors wrote. However, there are a limited amount of studies showing the reduction of mortality associated with implantable cardioverter-defibrillators (ICDs).

To study this further, George Wells, PhD, of University of Ottawa Heart Institute in Ottawa, and colleagues assessed the mortality associated with CRT with and without implantable defibrillators in 3,071 patients from 12 previous studies who were diagnosed with symptomatic and advanced heart failure (HF).

Studies included enrolled HF patients who received OMT that compared CRT with OMT alone or CRT plus implantable defibrillator with a standard ICD. The researchers used mortality as the primary endpoint.

Follow-up within the studies ranged from three to 40 months, 63 to 89 percent of the study population were men and the mean age ranged from 62 to 66 years. The mean left ventricular ejection fraction (LVEF) was 21 to 25 percent.

Wells and colleagues found that when CRT was added to treatment the relative risk reduction of morality was 22 percent. Within the five studies that evaluated the effect on mortality of CRT plus OMT therapy versus OMT alone, the researchers found a 27 percent relative risk reduction in mortality.

In the seven studies that reported mortality from the intervention of CRT and implantable defibrillation in addition to OMT, the researchers found a 17 percent risk reduction. The researchers found that a large reduction in mortality was seen in NYHA class II heart failure patients (20 percent).

“Our meta-analysis showed a significant reduction in mortality with cardiac resynchronization therapy in addition to either optimal medical therapy or an implantable cardioverter-defibrillator,” the authors concluded. “Cardiac resynchronization therapy may now be extended to a much wider proportion of patients with heart failure, improving long-term outcomes in this growing population.”