[The usefulness of portable 24-hour polygraphic monitoring--evaluation of autonomic nervous activity of the patients with ischemic heart disease by using heart rate variability during sleep].Fukuoka Igaku Zasshi. 1995 Feb; 86(2):40-57.FI
Portable 24-hour polygraphic monitorings were performed on 109 cases with neurological or cardiovascular disorders, sleep disturbances and metabolic diseases to clarify its usefulness and limitations. Moreover, an evaluation of autonomic nervous activity was done in different stages of sleep in normal young (n = 9), normal middle-aged subjects (n = 8) and patients with ischemic heart disease (n = 7) using power spectral analysis of heart rate. The parameters recorded in this study were electroencepharogram(EEG), electrooculogram, electromyogram of chin muscles, electrocardiogram, respiratory curve, walking pulse and body position. Using polygraphic monitoring, the patients with cardiac arrhythmia showed abnormal EEG in 20% and those with neurological events in 86.7%. The improvement of sleep structure was found after pacemaker implantation in the patients with bradyarrhythmias (75%). Time spans of slow wave sleep and REM sleep of patients with ischemic heart disease decreased significantly from 120.9 +/- 40.6 min to 79.1 +/- 25.3 min, 112.8 +/- 16.5 min to 63.6 +/- 23.6 min, respectively (p < 0.05). RR50, that is number of R -R intervals greater than 50msec compared to the preceding R-R interval, decreased significantly in each stage of sleep in the patients with ischemic heart disease compared to normal subjects (stage 2: 18.3 +/- 6.1/min to 3.8 +/- 3.0/min, p < 0.01; SWS: 7.8 +/- 8.0/min to 3.2 +/- 2.5/min, p < 0.05; REM: 17.9 +/- 6.0/min to 4.4 +/- 4.3/min, p < 0.01). The HF power in all stages of sleep showed a trend of the decrease in the patients with ischemic heart disease. In REM sleep, the LF power in patients with ischemic disease was lower significantly compared to that in normal middle-aged subjects (6.1 +/- 3.2 to 12.1 +/- 4.1, p < 0.05). The L/H ratio also decreased significantly (1.08 +/- 0.30 vs. 2.35 +/- 1.03, p < 0.05). The slope of 1/fx above 0.15Hz in IHD patients was less in stage 2 (-0.404 +/- 0.280 vs. -0.849 +/- 0.183, p < 0.01) and in REM sleep (-0.294 +/- 0.368 vs. -0.665 +/- 0.291, p < 0.05). Above results suggest the involvement of a decrease of sympathetic activity in addition to decrease of parasympathetic activity especially in REM sleep in the patients with ischemic heart disease. In conclusion, polygraphic monitoring is useful for a detection of abnormality of EEG and an evaluation of autonomic activity in cardiovascular disorders.