Objectives and background. Decreased heart rate variability(HRV) has been shown to reflect disturbances of the autonomic nervous systemthat is related to increased cardiovascular mortality. The majority of studiesinvestigated HRV in patients with systolic left ventricular dysfunction due toremote myocardial infarction or dilated cardiomyopathy. To date, only few dataare available on HRV in patients with predominant diastolic dysfunction in thepresence of cardiac hypertrophy of different etiologies.

Methods. Time domain analysis of HRV was performed fromdigital 24 hour Holter ECG recordings in 86 patients with sinus rhythm andcardiac hypertrophy, which was due to aortic valve stenosis in 33 patients,hypertrophic cardiomyopathy in 29 patients, and hypertensive heart disease in24 patients. HRV analysis was compared with 91 healthy controls.

Results. Standard deviation of all normal-to-normalRR-intervals (SDNN) was reduced in patients with aortic valve stenosis,hypertrophic cardiomyopathy, and hypertensive heart disease when compared withcontrols (SDNN 119 ± 42 vs. 154 ± 36 ms, P<0.001). The extent ofcardiac hypertrophy indexed by echocardiography based left ventricular masscalculation and increased patient age were independent predictors fordepression of SDNN.