ASSESSMENT OF SUBRENAL BANDING OF THE ABDOMINAL-AORTA AS A METHOD OF INDUCING CARDIAC-HYPERTROPHY IN THE GUINEA-PIG

The aims of this study were to develop a model of left ventricular hyp ertrophy in the guinea pig using the technique of aortic banding below the level of the renal arteries, and to characterize any cardiac elec trophysiological changes induced. Female guinea-pigs were either sham operated or the abdominal aorta was partially occluded by banding arou nd a 23 or 25G needle. Following recovery, animals were monitored for 10 weeks. The left ventricular dry weight to body weight ratio was sim ilar in sham (0.326 +/- 0.01 mg/g, n = 12) and aortic banded guinea pi gs (0.308 +/- 0.1 mg/g, n = 11). Conscious mean arterial blood pressur e was also not modified by the aortic banding 10 weeks after operation (72 +/- 16 (sham) vs 71 +/- 1 mmHg). The action potential characteris tics measured in isolated superfused left papillary muscle stimulated at 1 Hz were similar in sham and aortic banded groups. The action pote ntial duration measured at 50 and 90% of repolarization tended to be l onger in muscle from aortic banded (122.4 +/- 10 ms ADP(50) and 155.2 +/- 9.5 ms APD(90)) than sham operated animals (105.8 +/- 8.4 and 142. 2 +/- 6.2 ms) but these differences were not statistically significant . Hypoxia abbreviated the cardiac action potential to a similar degree in muscle from sham and aortic banded animals. It is concluded that s ub-renal aortic banding with a 23 or 25G needle fails to develop left ventricular hypertrophy in the guinea pig 10 weeks after operation.