Sleep-disordered breathing and inappropriate defibrillator shocks in chronic heart failure

Supraventricular tachyarrhythmias are a major cause of inappropriate defibrillator shocks. Sleep-disordered breathing (SDB) is a known risk factor for atrial fibrillation (AF). We hypothesized that Cheyne-Stokes respiration (CSA) and obstructive sleep apnea (OSA) have an impact on inappropriate defibrillator discharges in patients witch chronic heart failure (CHF) and cardiac resynchronization therapy with defibrillator (CRT-D).

In this study, 172 patients with CHF (LVEF ≤ 45 %, NYHA-class ≥ 2) and CRT-D underwent overnight polygraphy; 54 had no SDB (apnea-hypopnea index < 5/h), 59 had OSA, and 59 had CSA. During follow-up (36 months), inappropriate defibrillator shocks were documented.

In all, 17 patients had inappropriate defibrillator shocks (9.9 %; eight oversensing due to lead fractures, five caused by atrial fibrillation, four because of sinus tachycardia). Mean event-free survival time was 33.5 ± 1.2 months in the CSA group, 35.2 ± 0.7 months in the OSA group, and 32.1 ± 1.5 months in the no SDB group, respectively (CSA vs. no SDB p = 0.63; OSA vs. no SDB p = 0.31; CSA vs. OSA p = 0.45). Stepwise Cox proportional hazard regression analysis revealed an independent association for age (per year: hazard ratio 0.90, 95 % confidence interval 0.85-0.96, p < 0.001), but not for any kind of SDB.

SDB was not associated with inappropriate defibrillator shocks. We assume this is due to the low incidenceand low proportion of inappropriate therapies in response to AF.