Abstract
Considering from clinical implication, it is often complained that short-term experimental diseased heart models do not mimic long-term diseased hearts that one often clinically encountered. The aim of the present study was (i) to compare left ventricular function between rat cardiac hypertrophy models treated with isoproterenol for 3 days (Iso 3d) and 7 days (Iso 7d) by pressure-volume measurements with catheter method and (ii) to follow up the left ventricular function in the same model treated with Iso up to 16 weeks with a less-invasive echocardiography. Infusion of either Iso (1.2 mg·kg−1·day−1 for 3 days–16 weeks) or vehicle (saline 24 µl·day−1 for 3 days–16 weeks; Sa group) was performed by subcutaneously implanting osmotic minipump. There were no significant differences in systolic pressure-volume area at midrange left ventricular volume (PVAmLVV: a mechanical work capability index) between Iso 3d and 7d groups, although PVAmLVV in both groups was significantly reduced from that in Sa group. From echocardiography, the left ventricular function of the hypertrophy models at 3 day, 1 and 2 weeks was unchanged but the model at the longer-term than 4 weeks resulted in prolonged systolic failure. The results indicated that (i) no marked differences in the left ventricular mechanical work capability were found between Iso 3d and 7d groups; (ii) only 3-day Iso infusion induced the hypertrophy model similar in shape and function to that induced by 2-week Iso infusion. We concluded that the 3-day model sufficiently represents the effects of 2-week Iso infusion.
