Effect of Inosie on left ventricular performance and its clinical significance

Inosine at the dose of 200 mg was administered via central vein to 16 cases of various cardiac diseases, including effort angina pectoris, myocardial infarction, valvular disease, idiopathic cardiomyopathy, and congenital heart disease. Left ventricular performance was assessed by the time-course of various hemodynamic parameters (pulmonary wedge pressure, heart rate, LVP, LVEDP, max dp/dt, dp/dt/P, and cardiac output) including ejection fraction in some cases. Inosine caused significant decrease in pulmonary wedge pressure ranged from-7% to -47% during 5 min period following injection. Significant decrease in LVEDP ranged from -4% to -67% was also observed. Meanwhile significant decrease in systolic left ventricular pressure (LVP) was observed. In patients with relatively low value of max dp/dt (less than 1,500 mmHg/sec), the increase ranged from 100 to 300 mmHg/sec (6% to 38%) except 1 case with hypertrophic obstructive cardiomyopathy. In all cases, increase in dp/dt/P ranged from 4% to 44% during 5 min period following injection. In addition, the ejection fraction increased slightly in 2 out of the 3 cases studied. Cardiac output increased in all cases except a normal case by 1% to 31% during the period of 5 to 10 min following injection. Change in the heart rate was not significant. Quantitative evaluation disclosed the beneficial effects of inosine on the left ventricular function through the remarkable load-reducing effect and the unequivocal positive inotropic effect, particularly in the cases of disturbed functions. In addition, mild coronary vasodilation action was also noted.