[Recent progress in Holter electrocardiography, focussed on heart rate variability].

Heart rate variability has attracted attention as an index of the effects of the autonomic nerve system on the heart rhythm. Heart rate variability (HRV) is low in patients at risk for sudden death. We evaluated the effects of caffeine, whole-day work without sleep and drugs on HRV. Caffeine had no effects on HRV or ventricular extrasystoles in young adults but aggravated those in obese middle-aged subjects. Whole-day work without sleep increased blood catecholamines and decreased HRV. These findings also suggest the usefulness of HRV as an index in health management. Tofisopam, enalapril and aprindine significantly improved HRV. These drug may be useful for maintaining normal autonomic nerve activity and preventing autonomic nerve diseases or sudden cardiac death in this stressful society.