Pathophysiological and clinical relevance of simplified monitoring of nocturnal breathing disorders in heart failure patients

Abstract

Nocturnal breathing disorders in the form of periodic breathing (PB) are very common in heart failure (HF) patients. There is an increasing interest in simple and affordable tools to screen patients and monitor these disorders at home on a long-term basis. We aimed to assess the pathophysiological and clinical relevance of a simplified method for monitoring of PB suitable to be self-managed by the patient at home. A night-time respiratory recording was performed in 397 optimally treated HF patients (age 60 +/- 11 years, NYHA class 2.4 +/- 0.6, left ventricular ejection fraction 29 +/- 7%) and the duration of PB (PB(Dur)) automatically computed. Patients were followed-up for 1 year and the prognostic value of PB(Dur) evaluated. In 45 patients, we assessed the association between PB(Dur) and severity of oxygen desaturations (number of desaturations >3%). Twenty six of the 397 patients died of cardiac causes. A PB(Dur) > or =2 h was significantly associated with an increased risk of cardiac death after adjustment for major clinical predictors [hazard ratio (95% CI): 3.5 (1.6-7.9), P = 0.002]. The correlation between PB(Dur) and severity of desaturations was 0.94 (P < 0.0001). Relevant pathophysiological and clinical information can be obtained from simplified monitoring of breathing disorders managed by the patient. These results provide new perspectives in the investigation of the clinical impact of abnormal breathing in HF patients.