A computer application for the investigation of cardiac autonomic effects of sleep-disordered breathing in heart failure patients

Sleep-disordered breathing (SDB) in the form of periodic breathing is common in heart failure patients and is thought to increase sympathetic activity. Since heart rate (HR) cyclically increases during SDB in synchrony with the oscillation in ventilation, these increases have been interpreted as indirect evidence of an augmented adrenergic activity brought about by SDB. To support this hypothesis, however, the distribution of HR fluctuations during SDB has to be compared with the distribution of spontaneous HR variation during normal breathing within the same night. The aim of this work was to develop a computer application to carry out this task efficiently, analyzing HR across different sleep stages, breathing conditions and abnormal breathing type (obstructive and central). The system automatically selects homogeneous segments of HR from standard polysomnographic recordings and computes a set of relevant distribution descriptors of HR. A pilot testing of the system has been performed in five stable heart failure patients.