[The thickness/radius ratio (t/r) in patients with dilated and hypertrophic cardiomyopathy]

We studied 17 patients with cardiomyopathy (10 hypertrophic and 7 dilated). With two-dimensional echocardiography, we obtained a short axis view at the level of papillary muscle. We calculated the ratio between thickness (h), of ventricular wall and cavity's radius (r) in diastole and systole (h/r ratio). Hypertrophic cardiomyopathy has a high h/r ratio in diastole (inappropriate hypertrophy), hypercontractility and low and systolic wall stress. Dilated cardiomyopathy has a low diastolic h/r ratio (inadequate hypertrophy) with low contractility and elevated end-systolic, wall stress. We discuss the mechanisms and consequences of different patterns of hypertrophy on the ventricular performance.