Sleep apnoea as a predictor of mid- and long-term outcome in patients undergoing cardiac resynchronization therapy

Aims To assess the impact of baseline apnoea–hypopnoea index (AHI) on mid-term outcome and its change after 6 months of cardiac resynchronization therapy (CRT) on remote outcome. Methods and results In 71 patients with CRT devices, Holter-derived AHI was assessed before and 6 months after the procedure. Baseline AHI >20 was considered abnormal. After 6 months of CRT, a 50% decrease of baseline AHI was considered significant and stratified patients into AHI dippers and non-dippers, except those who preserved normal AHI. Prognostic value of baseline AHI and its change were assessed in relation to mortality and major cardiac events (MACE). More patients with an abnormal AHI died during 6 months follow-up ( P = 0.02), especially due to sudden cardiac death. MACE-rate was insignificantly higher in abnormal AHI patients. Significantly higher mortality ( P = 0.001), especially due to heart failure progression and higher MACE-rate ( P < 0.001) during further observation were observed in AHI non-dippers. In multivariate analysis, the absence of AHI reduction was an independent predictor of mortality [hazard ratio (HR) 6.56, P = 0.015)] and MACE (HR 6.05, P = 0.002). Conclusions Abnormal baseline AHI identifies patients prone to death during mid-term observation. Lack of AHI reduction after 6 months of CRT is an independent risk factor of death and MACE during further follow-up.