Severity of spleep apnea syndrome and life‐threatening tachyarrhythmias in patients with implantable cardioverter defibrillator

Abstract

Background: Sleep apnea syndrome (SAS) has been reported to be associated with a higher incidence of ventricular arrhythmias. The aim of this study was twofold: (1) to investigate whether in SAS patients receiving an implantable cardioverter defibrillator (ICD) the severity of SAS was associated with the occurrence of ventricular arrhythmias; (2) to assess whether changes in nocturnal apnoic/hypopnoic episodes may favor the occurrence of life-threatening arrhythmias, that is, sustained ventricular tachycardia (VT)/fibrillation (VF), requiring ICD intervention. Methods:We enrolled 46 patients with documented SAS at polysomnography (apnea/hypopnea index [AHI] > 5) who also had a left ventricle ejection fraction (LVEF) < 35% and, according to primary prevention indications, implanted an ICD (Boston Scientific Incepta) able to daily monitor apnoic/hypopnoic episodes occurring during sleep. Patients were followed at 3-month intervals.Results: At a mean follow-up of 18 months, 21 episodes of sustained VT/FV requiring ICD intervention were documented in eight patients (17.4%). Baseline AHI was significantly higher in patients with compared to those without ICD intervention. ICD interventions, however, were not preceded by any worsening of apnoic/hypopnoic episodes.The respiratory disturbance index (RDI) of the week during the event, indeed, was not different from that recorded during the previous 2 weeks (25.4 ± 11, 25.6 ± 10 and 25.1 ± 10, respectively; p = .9). Conclusions:In patients with SAS who received an ICD for primary prevention of sudden death, those with ICD interventions showed a more severe form of the disease at baseline. ICD interventions, however, were not preceded by any significant changes in SAS severity.

Sleep-Disordered Breathing Destabilizes Ventricular Repolarization

“…The last decade has seen enormous growth in the evidence linking SDB to ventricular arrhythmias, and sudden cardiac death. 12,14,[39][40][41][42][43] Epidemiological data have shown that SDB is associated with a higher burden of complex ventricular ectopy (i.e., bigeminy, trigeminy, and quadrigeminy), non-sustained ventricular tachycardia, and sudden cardiac death. 11 A meta-analysis of 22 studies (42,099 participants) reported that the SDB-related relative risk for sudden death was 1.74 (95% CI: 1.40-2.10).…”