Continuous ambulatory blood pressure monitoring versus casual blood pressure in borderline hypertension.

In 56 patients with borderline hypertension, casual blood pressure was compared with average daytime ambulatory blood pressure. The difference between these two values ranged from -20 to +40 mm Hg and was unrelated to spontaneous blood pressure variability, the blood pressure fall during sleep, and the peaks of pressure recorded during the day. Heart rate and a family history of hypertension were not predictive of the degree of difference between casual and average daytime recorder pressure. Target organ damage was present in 44% of the patients and was more closely correlated with recorder than with casual pressure.