Systolic time intervals in children with heart disease.

Of the systolic time intervals, the preejection period is known to correlate well with invasively measured isometric contraction time, and increase of the quotient preejection period/left ventricular ejection time (PEP/LVET) is considered to be of a good indicator of left ventricular failure. The different systolic time intervals have been recorded from the carotid pulse curve from 40 normal children, 20 aged five and 20 aged ten years. Their PEP/LVET was 0.31 +/- 0.04. Seventy-eight children with different heart diseases were then investigated. In patients with congenital total heart block or extrasystoles, there was a negative correlation between PEP/LVET and the R-R interval, in accordance with the Frank-Starling law. In patients with ventricular septal defects PEP/LVET differentiates between small and large shunts; the increased PEP/LVET of the latter normalizes after operation. The increased PEP/RVET of children with transposition of the great arteries is an expression of the inadequacy of the right ventricle as a systemic chamber. In aortic stenosis "normalization" of a previously decreased PEP/LVET may indicate early left ventricular failure. In primary myocardial disease registration of the systolic time intervals enables us to follow the left ventricular function more closely than is possible with invasive techniques.