Effects of Na(+)-H+ exchange blocker amiloride on left ventricular remodeling after anterior myocardial infarction in rats.

We investigated the effects of amiloride, a Na(+)-H+ exchange blocker, on ventricular remodeling in an infarcted rat model. In the amiloride group, the left descending coronary artery was ligated and rats were given amiloride (1 mg/kg/day, n = 11) in their drinking water for 4 weeks. In the control group, rats were given water for 4 weeks (n = 8) after myocardial infarction. The rats were killed on day 28. Both the ratio of heart weight to body weight and that of left ventricular weight to body weight were significantly less in the amiloride group (p < 0.05). The diameter of a myocardial fiber in the region adjacent to the operated area was significantly reduced in the amiloride group compared with the control group (p < 0.05). Left ventricular cavity dimension was significantly smaller in the amiloride group than that in control group (p < 0.05). Our findings suggest that amiloride prevents ventricular remodeling after myocardial infarction.