Atrial Fibrillation Is Independently Associated with Mortality, Heart Failure Hospitalizations And Appropriate Therapies in ICD Recipients

Aims: Atrial fibrillation (AF) is associated with increased morbidity and mortality in the general population. However, data regarding clinical and arrhythmic events of AF patients implanted with implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRTD) are limited.

Methods: We compared the risk for clinical events (heart failure and all-cause mortality) and arrhythmic events (appropriate and inappropriate therapy) by the presence of AF among 6694 patients who were enrolled and prospectively followed-up in the national ICD registry.

Results: Patients with AF (n=1414 (26.8%)) were older, had more severe heart failure, previous cardiac pacemaker or implantation of CRTD (all p<0.05), but similar ejection fraction and frequency of ischemic cardiomyopathy (all p=NS). Kaplan-Meier survival analysis showed that at 34 months of follow-up, patients with AF had significantly higher all-cause mortality: 31.1% vs. 18.4%, respectively (p<0.0001); heart failure hospitalizations: 17.2% vs. 11.5%, respectively; (p<0.0001); and appropriate ICD therapies: 14.9% vs.11.2%, respectively (p=0.003) in comparison to patients without AF. There was no significant difference in inappropriate ICD therapies: 4.2% vs. 3.1%, respectively (p=0.107). There was no difference in mortality, heart failure hospitalizations or appropriate therapies between patients with different types of atrial fibrillation. Multivariate analysis, which included comorbidities, presence of ischemic heart disease, heart failure and LVEF showed that AF was an independent significant predictor of the risk for all-cause mortality (HR=1.78, CI 1.57-2.01; p<0.0001), heart failure hospitalizations (HR=1.44, CI 1.13-21.82; p=0.003) and appropriate ICD therapies (HR=1.48, CI 1.15-1.92; p< p=0.003). Atrial fibrillation was associated with mortality in both ICD and CRTD recipients (p<0.0001 in both groups).

Conclusion: In the real world setting AF affects above one quarter of the ICD/CRTD recipients, and is independently associated with increased risk for adverse clinical and arrhythmic events.