Persistent Atrial Fibrillation Is Associated With Appropriate Shocks
Aim: The objective of this study was to investigate whether persistent atrial fibrillation (AF) and new-onset AF are associated with appropriate shocks, cardiovascular mortality, chronic heart failure (CHF), and inappropriate shocks in implantable cardioverter defibrillator (ICD) patients with left ventricular dysfunction.
Methods: We included 290 consecutive ICD patients with a documented left ventricular ejection fraction ≤0.35 and compared outcomes between patients without AF (n = 207), those with persistent AF (n = 64), and those with new-onset AF (n = 19).
Results: The patients with persistent AF were older, more frequently had valve disease and cardiac surgery, and less frequently had coronary artery disease as compared with the patients without AF. Patients with persistent AF had a higher New York Heart Association class, however, left ventricular ejection fraction rates between these 2 groups were comparable (0.28 ± 0.07 vs 0.29 ± 0.08, P = not significant). No difference was found between patients with new-onset AF and those without AF. During follow-up (2.6 ± 1.9 years), more patients with persistent AF received appropriate ICD shocks as compared with those without AF (24 [38%] vs 49 [24%], P = .04). Deterioration of CHF occurred more often in patients with persistent AF (19 [30%], P = .001) and those with new-onset AF (9 [47%], P < .001) as compared with patients without AF (31 [14%]). Multivariate analysis revealed that patients with persistent AF had an increased risk for appropriate ICD shocks (adjusted hazard ratio [HR] 1.9, 95% CI 1.2-3.2, P = .009). Persistent AF (adjusted HR 2.1, 95% CI 1.1-3.9, P = .03) and new-onset AF (adjusted HR 2.5, 95% CI 1.1-5.7, P = .02) were found to be independent risk indicators of CHF deterioration.
Conclusions: In ICD patients with left ventricular dysfunction, persistent AF is associated with appropriate ICD shocks and deterioration of CHF. New-onset AF is related to deterioration of CHF.

Atrial fibrillation (AF) is the most common cardiac arrhythmia and often occurs together with chronic heart failure (CHF). The prevalence of AF increases with the severity of CHF, up to 40% among patients in New York Heart Association (NYHA) class IV for CHF. Data on the impact of AF on cardiovascular morbidity, implantable cardioverter defibrillator (ICD) shocks, and mortality in the setting of CHF are ambiguous. Several studies reported no independent impact of AF on mortality, whereas others reported the opposite that AF is a risk factor for mortality in CHF. It may be that the impact of AF on mortality depends on the severity of concomitant CHF, being most prominent in moderate CHF. Furthermore, the cause of death among patients with AF and CHF is at present unknown and may be multifactorial, including progression of CHF, ventricular tachyarrhythmias, stroke, bleeding caused by anticoagulation, and drug toxicity. The association between AF and appropriate ICD therapy has been reported by several investigators.

The objective of this study was to investigate whether persistent AF and new-onset AF are associated with appropriate ICD shocks, CHF deterioration, cardiovascular mortality, and inappropriate ICD shocks in patients with left ventricular dysfunction and an ICD.