The effect of intravenous captopril on right and left ventricular load and function in moderate-severe essential hypertension.
The acute haemodynamic effects of intravenous captopril were measured, and left ventricular function was analysed by radionuclide angiography in eleven patients with moderate to severe hypertension. All subjects received 1 mg captopril by bolus injection initially, followed at 10 minute intervals by 2 mg or 5 mg injections according to blood pressure response. Eight patients experienced an acute reduction of blood pressure whilst three patients remained unresponsive. The onset of action was within 5 minutes with a peak effect at 5 to 10 minutes and duration of action lasting 20 to 30 minutes. The haemodynamic effects were characterised by arteriolar dilatation (reduced systemic vascular resistance P less than 0.01), and apparent venous dilatation (reduced right atrial, pulmonary wedge pressure, P less than 0.05 and 0.01 respectively). Pulmonary vascular resistance was not altered, ejection fraction remained unchanged and isovolumic relaxation period was lengthened (119 +/- 20.1 to 147.39 +/- 21.15, P less than 0.05). Coronary perfusion pressure gradients dropped (123.8 +/- 5.6 to 107.1 +/- 11.3 mmHg, P less than 0.001) following intravenously administered captopril. Intravenous captopril is effective in reducing arterial pressure rapidly with minimal adverse effects. This suggests that it may be useful as an alternative regimen for severe hypertension. The prolongation of the isovolumic relaxation period accounted for the decrease of coronary filling load.
Chen
Y T
YT
Division of Cardiology, Taichung Veterans General Hospital, Taiwan, Republic of China.
Lee
D Y
DY
Hwang
Z F
ZF
Tsai
Z H
ZH
Chang
F J
FJ
Chiang
B N
BN
D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged
D002216:Captopril