Journal of cardiovascular pharmacology
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J. Cardiovasc. Pharmacol. · Jan 1981
Review Comparative StudyHemodynamic changes after acute and long-term combined alpha--beta-adrenoceptor blockade with labetalol as compared with beta-receptor blockade.
The hemodynamic pattern in hypertension varies according to the age of the subject and the stage of the hypertensive disorder. In the early stage, both cardiac output and systemic vascular resistance tend to be elevated. Already at that stage, mild degrees of left ventricular function disturbance can be detected. ⋯ Combined alpha--beta-adrenergic blockade lowers blood pressure predominantly by alpha-adrenoceptor-mediated reduction of systemic vascular resistance both when induced acutely and during long-term administration. Owing to its beta-adrenoceptor blocking component, the increase of cardiac output is abolished: cardiac output is maintained at pretreatment levels, as is left ventricular filling pressure. Since a well-balanced blockade of both alpha- and beta-adrenergic receptors counteracts the hemodynamic changes occurring in the course of hypertension and tends to restore cardiovascular dynamics towards normal, combined alpha--beta-adrenoceptor blockade appears to be one of the most logical and rational therapeutical approaches to hypertension.
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J. Cardiovasc. Pharmacol. · Sep 1980
Clinical and hemodynamic effects of dobutamine in acute myocardial infarction with left heart failure.
We studied the clinical and hemodynamic effects of dobutamine infused for 24 hr into 10 patients with acute myocardial infarction (less than 4 days) complicated by left heart failure (pulmonary wedge pressure greater than 15 mm Hg, cardiac index less than 3.0 liters/min/m2). We measured pulmonary arterial pressures, pulmonary wedge pressure, right atrial pressure, and intravascular systemic blood pressures. The thermodilution method was used for determinations of cardiac output, and the electrocardiogram was followed with a computerized arrhythmia monitoring system. ⋯ After 24 hr of dobutamine infusion, much of the improvement in left ventricular function was lost. This may be attributed either to a decrease of drug action or to an unfavorable evolution of the clinical status. We conclude that infusion of dobutamine is an effective, potent, and well-tolerated short-term procedure in the management of left heart failure during the acute stage of myocardial infarction.