Class III congestive heart failure was independently associated with an increased risk of appropriate ICD discharge for ventricular arrhythmias (HR 2.40; 95% CI 1.16-4.98).
Cohort (n=1,140)
Yes
Is the severity of congestive heart failure (NYHA class) associated with an increased risk of appropriate ICD discharges for VT/VF in patients with ICDs?
Class III heart failure is an independent risk factor for ventricular arrhythmias requiring shock therapy in patients with ICDs, particularly when combined with severely reduced LVEF.
Effect estimate: HR 2.40 (95% CI 1.16-4.98)
BACKGROUND: Left ventricular ejection fraction (LVEF) predicts device discharges in patients with implantable cardioverter-defibrillators (ICDs). The relationship between severity of congestive heart failure (CHF) and ICD discharges is less clear. METHODS AND RESULTS: We prospectively analyzed the association between CHF and risk of appropriate ICD discharges in the Triggers Of Ventricular Arrhythmias (TOVA) study, a cohort study of ICD patients conducted at 31 centers in the United States. Reported shocks were confirmed for sustained ventricular tachycardia (VT) or fibrillation (VF) by analysis of stored electrograms. Proportional hazards models included CHF categorized by New York Heart Association class. Baseline CHF was present among 502 (44%) of 1140 patients; 170 (34%) had class I, 230 (46%) had class II, 97 (19%) had class III, and only 5 (1%) had class IV symptoms. During median follow-up of 212 days, 92 patients experienced 1 or more appropriate ICD discharges. Class III CHF was associated in a statistically significantly manner with ICD discharge for VT/VF (hazard ratio 2.40, 95% CI 1.16 to 4.98), even with adjustment for LVEF. The combination of LVEF <0.20 and class III symptoms resulted in a particularly high risk of shocks for VT/VF (hazard ratio 3.90, 95% CI 1.28 to 11.92). CONCLUSIONS: Class III CHF, an easily accessible clinical measure, is an independent risk factor, along with LVEF, for ventricular arrhythmias that require shock therapy among ICD patients. Whether patients with class III CHF benefit to a greater degree from ICDs and whether aggressive treatment of CHF in ICD patients may prevent ventricular arrhythmias remains to be determined.
Whang et al. (Tue,) conducted a cohort in Implantable cardioverter-defibrillator (ICD) patients (n=1,140). Class III congestive heart failure vs. Other NYHA classes or no congestive heart failure was evaluated on Appropriate ICD discharges for sustained ventricular tachycardia (VT) or fibrillation (VF) (HR 2.40, 95% CI 1.16-4.98). Class III congestive heart failure was independently associated with an increased risk of appropriate ICD discharge for ventricular arrhythmias (HR 2.40; 95% CI 1.16-4.98).