[Systolic time intervals in essential hypertension. I. Study of untreated patients].

15 patients with Stage II (VHO Classification) hypertension were studied before treatment. The following systolic time intervals were measured: 1) total electromechanical systolic period (QS2); 2) left ventricular ejection time (LVET); 3) interval between the first and second sounds (S1 S2); 4) pre-ejection period (PEP); 5) interval between the start of QRS and the first sound (QS1); 6) isovolumetric contraction time (ICT); 7) PEP/LVET ratio. The values measured were compared to the theoretical values obtained by the Weissler regression methods, taking into consideration the sex of the patient and the heart rate. QS1 and the ICT were both a slightly longer than normal; the PEP was increased by 25.6% (26.8 ms), whilst the LVET was decreased by 7.9% (24.0 ms), both differences being significant; QS2 increased by 1.1% (to 4.9 ms) but this was not significant; the PEP/LVET ratio was 0.479 +/- 0.12. These results seem to characterise moderate systemic hypertension with a significant relation between the variations of PEP, LVET and PEP/LVET with the diastolic blood pressure; although they have no absolute value, these results may be used in a longitudinal study to follow the course of hypertension and to study the effects of treatment.