Benefit of cardiac resynchronization in elderly patients: results from the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) and Multicenter InSync ICD Randomized Clinical Evaluation (MIRACLE-ICD) trials

Heart failure (HF) affects five million patients each year with both prevalence and incidence increasing with age. At least 20% of hospital admissions in patients > age 65 are due to HF. Cardiac resynchronization therapy (CRT) has been shown to improve HF symptoms and decrease mortality. However, little data are available which specifically address the effects of CRT in the elderly (> 65). We performed an analysis of the NYHA III/IV 839 patients randomized in the MIRACLE (n = 470) and MIRACLE-ICD (n = 369) trials. Both included patients with moderate to severe HF, ejection fraction (EF) a parts per thousand currency sign35%, and QRS duration a parts per thousand yen130 msec. Patients were grouped by age < 65, 65-75, and > 75 years. For each group, patients with CRT activated (ON) were compared with patients with CRT inactivated (OFF) for end points at 6 months, including New York Heart Association (NYHA) functional class and EF. Of the 839 patients, 368 were < 65, 297 were 65-75, and 174 were > 75 years old. Compared with controls, patients from all three age groups, whose CRT was activated, had statistically significant improvements in NYHA class (-0.84 for age < 65, -0.78 for age 65-75, and -0.78 for age > 75). All age groups with CRT ON also had statistically significant improvements in left ventricular EF (5.23%, 2.98%, and 4.03% respectively). There were no between group differences by age in LVEF improvement. In elderly patients enrolled in the MIRACLE and MIRACLE-ICD trials, CRT resulted in significant improvements in NYHA class and LVEF, regardless of age. These data suggest that the full age range of patients with appropriate indications for implantation can benefit from CRT.