Unloading effects of vasodilators on peripheral circulation and cardiac hemodynamics in patients with acute myocardial infarction.

Abstract

SUMMARYEffects of three representative vasodilators on peripheral and cardiac hemodynamics were studied in 20 patients with heart failure due to acute myocardial infarction (PCWP>18mmHg, Cl>2.20 L/min/m2) using venous occlusion plethysmography and a SwanGanz catheter. Sublingual isosorbide dinitrate (ISDN) significantly increased calf venous capacitance (CVC) from 5 to 60min (p<0.01) and calf blood flow (CBF) in the initial 15min (p<0.05), while simultaneously lowering PCWP (p<0.05) and central venous pressure (p<0.05). Calf vascular resistance (CVR), cardiac index, blood pressure, and total systemic peripheral resistance (TSPR) were not affected significantly. Nitroglycerin ointment (NGO) significantly decreased CVR (p<0.05) and increased CVC (p< 0.05) from 60 to 240min, simultaneously with lowering of PCWP (p<0.01), central venous pressure (p<0.05), and TSPR (p<0.05). Oral prazosin (Pz) increased CBF (p<0.01) and CVC (p<0.05) from 60 to 240min, simultaneously with significant lowering of PCWP (p<0.01) and TSPR (p<0.05), resulting in increased stroke work index (p<0.05). These data confirm that ISDN predominantly causes capacitance vessel dilatation and reduce excessive venous return, while Pz and NGO dilate not only capacitance vessels but also resistance vessels, consequently reducing systemic vascular re-

Cardiac function and peripheral circulatory adjustments in patients with acute myocardial infarction Observations during the early stage of AMI.

“…Vasodilator therapy is now commonly used in the management of heart failure complicating AMI and this supports the present findings regarding the peripheral vascular pathophysiology of AMI. 33) …”