[Rhythm analysis of individual 24-hour blood pressure profiles of patients with essential hypertension].

Circadian rhythms in ambulatory blood pressure profiles of eight primary hypertensive patients were analyzed by nonlinear fit of a combined cosine function. Significant circadian variation in systolic blood pressure was found in each patient, and in diastolic blood pressure in seven out of eight patients. The eight primary hypertensive subjects revealed typical circadian blood-pressure profiles with two daytime maxima and a single nighttime minimum. Whereas daytime maxima differed between the subjects, all nighttime minima occurred within a narrow range of 1:54 a.m. to 4:42 a.m. The PHARMFIT-program allows to analyze in more detail the circadian blood pressure profiles obtained by ABPM in single patients as well as in a group of hypertensives.