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

Purpose 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). Methods 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) ≤35%, and QRS duration ≥130 msec. Patients were grouped by age 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. Results Of the 839 patients, 368 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 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. Conclusions 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.