[Myocardial hypertrophy in aortic insufficiency as a compensation mechanism. Implications for surgical indication].

We studied 24 patients with pure and severe aortic regurgitation. Using 2-D Echocardiography we obtained parasternal short axis view and calculate the thickness/radio (H/r) ratio and with apical four chambers and two chambers view the ejection fraction (E.F.) with biplanar Simpson technic. The patients were divided in three groups: I) those (12) with E.F. and H/r ratio within normal limits; II) those (6) with low H/r ratio and normal E.F. and the third group III) was formed with 6 patients whom had low H/r ratio and E.F. Three patients from group I had surgical treatment without mortality; all but one (bacterial endocarditis) are alive after two years; five patients from group II had surgical treatment and everyone is alive in functional class I in the same period. All patients of the third group III but one (that had surgical treatment) are death in spite of medical treatment. We conclude that the optimal moment for surgical procedure in severe aortic regurgitation can be determined when the hypertrophy does not compensate the hemodynamic overload (decreases H/r) but the cardiac performance (E.F.) is normal. In this moment the surgical mortality is low and the procedure can change the natural history of the disease.