Twenty-Four Hour Arterial Pressure and Heart Rate As Predictors of Left-Ventricular Hypertrophy

Hypertrophy of the left ventricle occurs in some but not all hypertensive patients. The present study was designed to examine the office and the 24-hour arterial pressure (AP) and heart rate (HR) recordings, and the AP response to physical stress in two age- and sex-matched hypertensive groups who differed in their left- ventricular mass (LVM). In addition, we tried to determine whether AP and HR measured at rest, under stress, or with 24-hour AP monitoring correlate with LVM. Ten hypertensive subjects with left-ventricular hypertrophy (LVH) made up the study group and 10 hypertensive subjects without LVH made up the control group. Antihypertensive medication was withdrawn at least four weeks prior to evaluation. The mean office AP measured during the washout period was 157 ± 13/100 ± 11 mm Hg in the study group and 157 ± 17/104 ± 7 mm Hg in the control group. However, 24-hour AP monitoring disclosed that the study group had significantly higher AP than the control group during both day and night. The control group had a significantly faster HR in the clinic and at night. The HR response to bicycle exercise was less in the control group than in the LVH group. The maximal AP and the rise in AP during bicycle exercise did not differ between groups. The LVM index did not correlate with the office AP or with maximal AP during effort, but did correlate negatively with the office HR and with the HR prior to the exercise test. The most significant correlations were found, in decreasing order, between LVM and daytime systolic AP, night systolic AP, and daytime diastolic AP. The hypertensive patients without LVH had a significantly higher ratio of office/ day ambulatory mean AP than did those with LVH. In these patients without LVH, the “white coat” phenomenon may be an important cause of the elevated office AP, hence the importance of 24-hour ambulatory AP monitoring in identifying those subjects who will develop LVH.