Nocturnal blood pressure reduction and development of left ventricular hypertrophy in patients with treated essential hypertension

Background: Decreased blood pressure (BP) during the night may serve as a means of recovery for the cardiovascular system. No such decrease may represent a burden, possibly related to end organ damage not recognized by casual measurements. The purpose of this study was to evaluate the relationship of circadian BP to left ventricular hypertrophy (LVH) in hypertensives as documented by echocardiography and/or 12-lead electrocardiogram (ECG). Methods: The subjects were 26 hypertensive patients who had been followed-up and treated at the University Hospital in Basel for 3-18 years and whose ECGs were suitable for determining the presence or progression of LVH. Ambulatory BP was taken in all patients, and echocardiographical measures could be obtained in 20 patients. Signs of LVH in ECG and echocardiography were correlated with circadian BP. Results: Eight of the 26 patients had ECG signs of LVH although their office BP did not differ from that in the group without ECG evidence of LVH. Ambulatory BP recordings followed a different pattern in that only patients with ECG signs of LVH showed no reduction in night-time BP; daytime BPs were similar in both groups. The 10 patients who had echocardiographic signs of LVH did not show a night-time reduction in BP while those without did, and a significant one. Conclusions: Lack of night-time BP reduction may be important for the development of, or the lack of regression of, LVH in hypertensives despite apparently good control during office measurements.