INFLUENCE OF LEFT-VENTRICULAR HYPERTROPHY ON HEART PERIOD VARIABILITYIN PATIENTS WITH ESSENTIAL-HYPERTENSION

Objective: To evaluate whether left ventricular hypertrophy in hyperte nsive patients is associated with a greater impairment of sympathovaga l balance assessed by means of heart period variability. Design and Me thods: Forty hypertensive patients, 20 with echocardiographic evidence of left ventricular hypertrophy and 20 without, and 20 control subjec ts, were subjected to 24 h blood pressure monitoring and Holter record ing on 2 consecutive days. Power spectrum analyses of heart period var iability were performed utilizing the fast Fourier transform algorithm . Results: No difference was detectable in 24 h, daytime and night-tim e blood pressure values between hypertensive patients with and without left ventricular hypertrophy. Low- and high-frequency powers were hig her in controls than in hypertensives; in particular, low-frequency po wer showed a progressive decrease through control subjects and hyperte nsives without and with left ventricular hypertrophy. Furthermore, sig nificant negative correlations were found between left ventricular mas s index and low- and high-frequency power. No difference was detectabl e in ultra-low- and very low-frequency power. During daytime low- and high-frequency power were higher in controls than in hypertensives; du ring night-time, low- and high-frequency power increased significantly in all groups and low-frequency power was still higher in control sub jects. Conclusions: Considering that, when analysed over 24 h Holter r ecording, low- and high-frequency power both reflected the parasympath etic modulation of heart rate, the present results demonstrate a paras ympathetic withdrawal in hypertension; this sympathovagal imbalance is greater in patients with cardiac hypertrophy and is related to the in crease in left ventricular mass.