Hypertension, Vol 2, 111-117, Copyright © 1980 by American Heart Association
Serial measurements of systolic time intervals: effects of propranolol alone and combined with other agents in hypertensive patients
MC Kyle and ED Freis
Systolic time intervals (STI) were recorded serially before and during 1
year of treatment in 367 hypertensive men. The patients were randomly
assigned, double-blind, to one of the following regimens: propranolol alone
(P), propranolol plus hydrochlorothiazide (P + T), propranolol plus
hydralazine (P + H), propranolol plus hydrochlorothiazide plus hydralazine
(P + T + H), or reserpine plus hydrochlorothiazide (R + T). Systolic time
intervals were calculated by a computer pattern- recognition and
measurement program. Diastolic blood pressure and heart rate (HR) decreased
with each treatment regimen. The preejection period (PEP) was prolonged
following P alone. The left ventricular ejection time (LVET), after
correction for HR, was shortened with P + T and R + T and prolonged after P
+ H. The PEP/LVET was reduced with P + H. The prolongation of PEP during
long-term administration of P is comparable with previous studies of its
acute effects and suggests a moderate decrease in left ventricular
performance. Calculation of STI also appears to be a useful method for
showing the effects of adding other antihypertensive agents.