Heart Rhythm Control During Sleep in Ischemic Heart Disease

This paper deals with a computer‐aided study of heart rate (HR) control during different sleep stages in 20 healthy volunteers and 75 ischemic heart disease (IHD) patients. In healthy subjects, the parasympathetic HR control was increased and the sympathetic control decreased during stages 1, 2, 3, and 4. REM sleep was characterized by a marked decrease in parasympathetic and a slight elevation in sympathetic contribution. Typical, “reduced” and “paradoxical” HP sleep patterns (HRSPs) were observed in IHD patients. The typical HRSP was similar to that observed in healthy subjects; the reduced HRSP was characterized by HR constancy, and the paradoxical HRSP by an HR increase in stages 3 and 4, and a decrease in REM sleep. The reduced HRSP was associated with the more frequent occurrence of cardiac abnormalities during REM sleep. HR oscillations during stage 2 depended on periodic apnoea episodes and were associated with cardiac abnormalities such as more frequent heart failure and cerebral blood flow disturbances, and overweight.