Abstract
To elucidate the influence of the heart rate on early diastolic time intervals (EDTI) - from the second heart sound to the point of mitral valve opening (IIA-MVO) and from MVO to the O point of the apexcardiogram(MVO-O) –, we studied the relationship between R-R interval and EDTI in 38 patients with atrial fibrillation (AF): 8 patients had AF alone, 7 additionally had hypertension, 7 idiopathic dilated cardiomyopathy, 6 hypertrophic cardiomyopathy,7 ischemic heart disease, and 3 hyperthyroidism (AF study). We also studied the change of EDTI during atrial pacing (80–140 beats/min) in 5 normal subjects (pacing study). The results were expressed by variation rate, calculated as (B-A/A) × 100 (A = EDTI at minimal R-R interval, B = maximal EDTI). AF study: The variation rates of IIA-MVO and MVO-O were 7.4 ± 5.2 and 7.1 ± 3.5%, respectively. A correlation was not found between the preceding R-R interval and EDTI. This finding was common in the diseases studied. Pacing study: The variation rates of IIA-MVO and MVO-O were 0.3 ± 0.1 and 0.2 ± 0.1%, respectively. The results indicate that EDTI were not affected by the heart rate which ranged from 50 to 140 beats/min, and thus EDTI are not necessarily to be corrected by heart rate.