MYOCARDIAL-INFARCTION WITH AORTIC BANDING - A COMBINED RAT MODEL OF HEART-FAILURE

The effect of additional abdominal aortic banding on parameters of hea rt failure was studied in male Wistar rats with myocardial infarction. Contractile function was studied 8-9 weeks after operation, with an i soprenaline dose response protocol, in a retrograde Langendorff perfus ion. Also, plasma noradrenaline concentration, infarct size and morpho logy were determined. Compared with controls, myocardial infarction/ao rtic banding animals showed a decreased contractile function, both at baseline and after maximal isoprenaline stimulation, and elevated nora drenaline levels (1316 +/- 94 vs 1909 +/- 174 pg/ml, both p < 0.05). I n myocardial infarction rats, baseline values, but not those after ino tropic stimulation were decreased, when compared with controls, while the calculated E-max was significantly decreased. In aortic banding ra ts, contractile parameters were not significantly impaired, compared w ith controls. Both myocardial infarction and the myocardial infarction /aortic banding animals, but not aortic banding rats, had a significan tly increased heart weight (1.4 +/- 0.04 g for controls vs 1.7 +/- 0.0 8 g for myocardial infarction and 2.0 +/- 0.12 g for myocardial infarc tion/aortic banding), and left ventricular cavity volume (19 +/- 1.4 m m(3) for controls vs 49 +/- 5.5 mm(3) for myocardial infarction and 48 +/- 4.3 mm(3) for myocardial infarction/aortic banding) compared to c ontrol animals. Infarct size was 36.0% and 39.4% for the myocardial in farction and myocardial infarction/aortic banding animals, respectivel y. We conclude that myocardial infarction/aortic banding provides a ne w experimental model, which may yield important information and pathop hysiology which allow evaluation of changes that may mimic clinical my ocardial infarction with concomitant hypertension.