In 15 patients with essential hypertension (but without coronary heart disease) simultaneous 24-h monitoring of the ST-segment and blood pressure was performed. Twenty-six periods with significant ST-segment depressions were recorded. In 10/26 periods with ST-segment depressions blood pressure was elevated, heart rate was increased in 20/26 ST-segment depressions. During nine periods with ST-segment depressions angina pectoris was reported, and 27 anginal attacks without ST-segment depressions were observed. These data show ischemic episodes in hypertensive patients without coronary heart disease being associated with spontaneous increases of blood pressure and/or heart rate.