Benefical Effects of Chronic Bunazosin （α1－blocker） Therapy on the Infarcted Left Ventricle of the Rats

To determine whether long-term hemodynamic improveement could be occurred, bunazosin was administered intravenously for 28 days to rats with different sized chronic myocardial infarction. Left ventricular and aortic pressures and aortic blood flow were measured in bunazosin-treated and untreated rats. Infarct size was determined histologically. In untreated rats, cardiac index decreased and total vascular resistance and left ventricular end-diastolic presure incresed progressively as a funcion of infarct size. Whereas, in bunazosin-treated rats, cardiac index and total vascular resistance were maintained in rats both with and without infarcts, and left ventricular end-diastolic pressure remained within normal limits in all expect those with large infarct size. Thus, long-term therapy of bunazusin attenuated the impairment of left ventricular performance that were observed in rats with chronic myocardial infarction.

α1-blocker

Myocardial infarction

Bunazosin