Experimental Ablation of Posterior as Contrasted to Anterior Aortic Cusp on Cardiac Hypertrophy in the Rabbit. ∗

Abstract

During the progress of studies on the results of digitization on experimental aortic insufficiency hypertrophy it was observed that the gross configuration of the hypertrophied heart appeared to differ. Some were globular in form whereas others were elongated or boot shaped. The hearts were dissected by removal of the auricles and division of the ventricular mass by the midseptal method. It was found that the globular heart was associated with ablation of the posterior leaflet and the right ventricular wall appeared to be considerably thickened along with the increased mass of the left heart. The coeur en sabot type, on the other hand, was found occurring usually in those that had destruction of the left anterior cusp. In the latter group the thickness of the right ventricular wall did not appear to be conspicuously increased in thickness, while the left ventricular wall was strikingly so. In a few hearts with combined lesions the configuration depended upon which leaflet damage was the more extensive. The obvious visual impression was substantiated by the weights of the ventricular masses and the ratios of these to one another as shown in Table I.

The hypertrophy of the auricles was observed to be greater in the hearts with posterior incompetency and the auricular body weight and the auricular heart weight ratios seem to confirm this. The heart weight body weight ratios show that the amount of total hypertrophy is almost uniformly greater in the hearts with posterior lesions. Difference in the intracardiac dynamics of the circulation with the two types of aortic regurgitation is the probable factor. A relative mitral stenosis (Austin Flint phenomenon) is a possible explanation of concomitant auricular and right ventricular hypertrophy in the presence of the regurgitation through the posterior sector.