[The normal values of systolic time intervals must be reviewed?]

A study of the relation between left ventricular ejection time (LVET) and arterial blood pressure (BP), was carried out in 26 healthy volunteers divided into 2 groups. A rise in BP was achieved in the first group of 2 subjects by venous infusion of 0.02% methoxamine solution. The heart rate was held constant by right atrial pacing and the arterial blood pressure was measured by catheterization of the right radial artery. A simultaneous recording of the electrocardiogram, the carotid arterial pulse and the arterial blood pressure tracings, was obtained. The relationship between LVET and the corresponding values of BP was examined by plotting LVET against BP. The second group of 24 subjects underwent a session of maximal isometric exercise. When the maximum of the effort was reached, the carotid arterial pulse tracing was recorded and the blood pressure of the arteria dorsalis pedis was measured by doppler technique. In both groups we plotted LVET against BP and HR. Simple and multiple regression equations were obtained. Our data show that LVET correlates with BP during the maximal isometric exercise and during venous infusion of methoxamine, suggesting that the normal values of systolic time intervals (STI) should be revised.