A ballistocardiographic study using Dock´s electromagnetic ballistocardiograph was made on 217 patients with essential hypertension, having no clinical evidence of congestive heart failure, electrocardiographic findings compatible with myocardial infarction or complaints suggestive of angina pectoris. This series included 137 men and 80 women ranging in age from 20 to 79 years.
The incidences of abnormal ballistocardiograms according to Dock´s classification were 50.5% in the third and fourth age-decade;68.5% in the fifth decade; 82.0% in the sixth decade; 85.7% in the seventh and eighth decade; and 70.5% for entire group. Thus, in the successive age-decades the occurrences of abnormal ballistocardiograms rosegradually from the third through the eight decade. The frequencies of abnormal ballistocardiograms in women were slightly higher than those in men in each age-decade group.
The incidences of abnormal ballistocardiograms showed a trend of progressive increase with increasing levels of both systolic and diastolic blood pressure. The frequencies of abnormal ballistocardiograms were 59.7% in those with normal electrocardiogram; 66.2% in those with electrocardiographic finding of left ventricular hypertrophy fulfilling voltage criteria alone, and 82.0% in those fulfilling voltage criteria and associated ST, T changes.
The mean amplitudes of IJ, HI and JK segments revealed a trend of progressive decrease with advancing age in both sexes, although some overlapping of individual measurement was noted.
The percentage of ratio of expiratory IJ amplitude to inspiratory IJ amplitude(IJE/IJI%) showed a tendency to decrease with advancing age in both sexes, whereas that of mean HI amplitude to mean IJ amplitude (HI_(M)/IJ_(M)%) showed no significant difference in each age-decade group in both sexes. The percentage of the ratio of mean JK amplitude to mean IJ amplitude(JK_(M)/IJ_(M)%) revealed a trend of progressive increase with advancing age and increasing levels of both systolic and diastolic blood pressure in both sexes.
Time interval between H,I,J,K wave tips of ballistocardiogram and R wave of electrocardiogram manifested no close relationship to age in either sexes and R-J and R-K interval in patients above the age of 50 were significantly longer in men as compared to those in women.
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