THE RELATIONSHIP OF AUTONOMIC FUNCTION TO AGE-RELATED-CHANGES IN LEFT-VENTRICULAR FILLING IN NORMAL SUBJECTS

Heart rate and age are independent variables associated with the patte rn of normal left ventricular filling. Since heart rate variability al so varies with age, the relationship between these and left ventricula r filling in normal subjects was assessed. In 31 subjects (age range 2 1 to 71 years), power spectral analysis ofhenrt rate variability was d etermined from 24 h Holter tapes, and left ventricular filling was ass essed by Doppler echocardiography. Relationships between heart rate va riability and left ventricular filling were assessed by univariate and multivariate regression analyses. Total, low frequency and high frequ ency power each significantly correlated with the peak filling velocit y with atrial systole (A) (r=-070, P<0.0001; r=-0.69, P<0.0001; r=-054 , P<0.01, respectively), but did not correlate with measures of early diastolic left ventricular filling. Although age and A were related (r =0.46, P<0.010), age was no longer a significant variable when measure s of heart rare variability were included in the multivariate regressi on model for A. Thus, the variability in measures of early diastolic f illing in normal subjects appears to be independent of measures of hea rt variability, whereas, A is significantly associated with these meas ures.