The use of systolic time intervals in the evaluation of antihypertensive treatment with metoprolol, labetalol and prazosin.

: 26 patients with moderate hypertension and no signs of heart failure were treated with metoprolol, labetalol or prazosin. Systolic time intervals (STI) were measured before and after several months of treatment. During treatment with metoprolol, a decrease in the preejection period index (PEPI), and preejection period/left ventricular ejection time ratio (PEP/LVET), was found. During treatment with labetalol or prazosin, a minor decrease in PEPI was observed, so that a significant decrease in PEP/LVET was not obtained. A decrease in PEPI and PEP/LVET may be due to improved cardiac performance, but in the given type of patients it is more dependent on the reduction in afterload. The STI measurement is less sensitive in discerning different mechanisms involved in lowering the blood pressure and cannot therefore be used for selecting the optimal antihypertensive drug.