[Effects of various diuretics on cardiac function in rats with heart failure].

Torasemide is a long-acting loop diuretic that combines the effects of both furosemide and spironolactone. It has been reported that torasemide but not furosemide might attenuate myocardial remodeling accompanied by left ventricular (LV) dysfunction. However, nothing is known about the effect of torasemide, long-acting loop diuretic and spironolactone, an aldosterone receptor antagonist in a rat model of chronic heart failure (CHF). Therefore, we compared the therapeutic effects of torasemide, furosemide and spironolactone on the progression of LV remodeling in a rat model of CHF after experimental autoimmune myocarditis (EAM). EAM was elicited in Lewis rats by immunization with porcine cardiac myosin. Twenty-eight days after immunization, rats were treated for 28 days with torasemide, furosemide and spironolactone. Diuretic actions, heart weight/body weight, heart rate, mean blood pressure, myocardial function by echocardiography, cardiac fibrosis, myocyte diameter and cardiac aldosterone synthetase (CYP11B2) were evaluated. Increased cardiac CYP11B2, severe LV remodeling and resultant cardiac dysfunction was found in CHF rats, whereas decreased cardiac CYP11B2, less remodeling and improvement of cardiac function were found in torasemide- and spironolactone-treated CHF rats. Our results indicate that torasemide and spironolactone treatment significantly improved cardiac function and LV remodeling compared with furosemide treatment.