24 h blood pressure profile affects the left ventricle independently of the pressure level. A study in untreated essential hypertension diagnosed by office blood pressure readings.

This work examines whether the 24 h blood pressure (BP) pattern per se might affect the left ventricular structure independently of the pressure level. One hundred subjects with abnormally high office BP readings who had never received any antihypertensive treatment were submitted to 24 h ambulatory BP monitoring and left ventricular echocardiographic assessment. They were classified into two groups, as follows: dippers (group 1), consisting of 46 subjects whose mean nighttime systolic BP was reduced by at least 10% in comparison to the corresponding daytime value, and nondippers (group 2), consisting of 54 subjects whose nighttime BP did not drop or was reduced by < 10%. Left ventricular mass and end-diastolic volume values, both normalized for body surface area, were significantly higher in nondippers (r = 3.12, P < .003, and r = 7.46, P < .001, respectively). The two groups did not differ in diastolic thickness of either intraventricular septum or left ventricular posterior wall (both values normalized for body surface area), in mean 24 h systolic or diastolic or average blood pressure, or in age. In conclusion, in untreated essential hypertension diagnosed on the basis of abnormal office BP readings, the higher incidence of left ventricular mass increase in subjects unable to reduce their blood pressure during the night was more due to left ventricular dilatation than to myocardial wall thickening. The effect of the 24 h BP profile on left ventricular volume appears to be independent of both the BP level and age.