Effects of long-term infusion of synthetic atrial natriuretic factor on hemodynamics and water input-output balance in patients with acute myocardial infarction.

The administration of atrial natriuretic factor (ANF) increases coronary blood flow and decreases coronary vascular resistance. However, little is known about the feasibility and reliability of intravenous long-term infusion of ANF in patients with coronary heart disease. We therefore examined the effects on hemodynamic parameters and water input-output balance of 24-hour administration of synthetic ANF (ANF-[99-126]: 20-50 ng/kg/min) in 8 patients with acute myocardial infarction (6 men and 2 women; mean age 55 years). The ANF infusion significantly decreased pulmonary capillary wedge pressure to a maximum of greater than 50% 4 hours after infusion (from 16 +/- 2 to 7 +/- 2 mmHg; p < 0.01), and the effect was sustained throughout the 24-hour infusion without diuresis (mean water balance, + 25 +/- 12 ml/hr). This reduction was significantly correlated with the baseline value before infusion (r = -0.85, p < 0.01). The effect on pulmonary capillary wedge pressure was accompanied by small reductions (approximately 20%) in systemic blood pressure and cardiac index, without significant changes in systemic vascular resistance and heart rate. These results indicate that prolonged administration of low to medium doses of synthetic ANF causes potent and sustained left ventricular unloading without reflex, tachycardia and volume depletion, and may thus be safe and have potential benefits for patients with coronary heart disease.