Mortality of heart failure patients after cardiac resynchronization therapy: identification of predictors

A direct comparison of survival benefits between cardiac resynchronization therapy-pacemaker (CRT-P) and defibrillator (CRT-D) was not yet performed, leaving clinicians to question whether CRT-P alone is enough to protect congestive heart failure (CHF) patients from sudden cardiac death and whether CRT-D should be implanted to all CHF patients indicated for biventricular pacing. This study attempts to make this type of comparison in a large CHF population and seeks to identify predictors of death in patients with different comorbidities.

Study population consisted of 542 consecutive patients who were implanted with either CRT-P (N = 147) or CRT-D (N = 395) between 1999 and 2005. Patients' clinical and follow-up data were entered in a prospective registry and retrieved for analysis. The primary endpoint of this study was all-cause mortality during follow-up. Total all-cause mortality was significantly lower among patients with CRT-D (18.5% vs. 38.8% of CRT-P, chi(2)= 25.11, P < 0.001). Patients with one of three comorbidities--chronic renal failure (OR = 4.885, P = 0.005), diabetes mellitus (OR = 4.130, P = 0.003), and history of atrial fibrillation (OR = 1.473, P = 0.036)--appeared to have higher risk of death, while treatment with beta-blocker (OR = 0.330, P = 0.002) or CRT-D device (OR = 0.334, P = 0.003) seemed to be associated with lower mortality.

Data from this nonrandomized study indicate that CRT-D has additional survival benefits over CRT-P. Given these findings, CRT-D should be recommended to most CHF patients with indications for biventricular pacing. After CRT implant, chronic renal failure, diabetes mellitus, and history of atrial fibrillation are strong independent predictors of death.