Short-Term Assessment of Left Ventricular Function, Coronary Hemodynamics, and Catecholamine Balance in Severe Congestive Heart Failure After a Single Oral Dose of Milrinone

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Abstract
Systemic and coronary hemodynamics were measured before and every 10 min after oral milrinone (10 mg) administration for 50 min, together with the drug plasma level in 14 patients with congestive heart failure. Left ventricular pressure (tip manometry), volume (angiography), and derived indexes were simultaneously assessed before and 60 min after milrinone treatment. Peak positive dP/dt, Vmax. and peak velocity of contractile element significantly increased 30 min after milrinone administration by 15%, 37%, and 30%. respectively. An increase in cardiac output (25%) with a consistent decrease in systemic vascular resistance (20%) occurred after 40 min without major changes in heart rate and aortic pressure. Right atrial pressure and minimal and end-diastolic left ventricular pressures decreased significantly after 50 min. by 30%, 25%, and 20%. respectively. Peak –dP/dt increased despite a slight change in end-systolic pressure. The time constants of relaxation. T1 and T2. significantly decreased by 15% after 50 min and by 16%. A transient but significant increase of 40% in coronary sinus blood flow was observed after 30 min. while myocardial oxygen consumption was unchanged 50 min after milrinone treatment. No changes were observed in catecholamine balance with milrinone. Ejection fraction increased significantly (22%) after milrinone administration, as well as the net work of left ventricle (27%). The increase of inotropism in failing hearts with a parallel reduction in preload and afterload makes milrinone a drug potentially useful in the oral treatment of severe heart failure.