Lower body mass index and atrial fibrillation as independent predictors for mortality in patients with implantable cardioverter defibrillator.

ABSTRACT

AIM: To evaluate risk factors related to total mortality in an unselected population of patients implanted with a cardioverter defibrillator. METHODS: Survival analysis was performed retrospectively investigating the records of 77 consecutive patients implanted with defibrillators (median 67 years, range 38-83 years; 63 men). All patients were followed regularly in 3-month intervals. The cause of mortality was assessed clinically, including post-mortem examination of device to assess possible arrhythmogenic death. Predictors were assessed by Kaplan-Meier analysis with log-rank tests and by Cox regression analysis (proportional hazards). RESULTS: Defibrillator recipients had a mean (+/-standard deviation) ejection fraction of 34+/-13%, left ventricular end-diastolic dimension (LVEDD) of 6.24+/-0.8 cm, QRS duration of 129+/-34 ms, and body mass index (BMI) of 26.4+/-4.3 kg/m(2). Atrial fibrillation was present in 32 patients, paroxysmal fibrillation in 23, and permanent fibrillation in 9 patients. The estimate of mean survival time for all patients was 51.5 (95% confidence interval 46.6-56.5) months. During the study period 11/77 (14%) patients died. Mean follow-up time was 24.5 months (range 0.2-60.7) for survivors and 7.6 months (range 1.5-42) for non-survivors. Independent predictors of mortality were the NYHA class (P=0.004), BMI< or =26 kg/m(2) (P=0.024), presence of paroxysmal or permanent atrial fibrillation (P=0.014), and absence of arterial hypertension (P=0.010). LVEDD showed a weak significant effect on survival (P=0.049). CONCLUSION: Patients with implantable cardioverter defibrillator and a normal to lower BMI or atrial fibrillation had a significantly higher overall mortality. These factors may be indicative of end stage heart failure or diseases associated with high sympathetic activation.