Deformation of the left ventricular wall during systole was analyzed using a magnetic resonance tagging technique.The subjects were two patients with dilated cardiomyopathy accompanied by a left bundle branch block. The circumferential strain at the short-axis section was employed as an index for evaluating cardiac contractility. The results showed that the circumferential strains in the septal walls of the patients were different from those of healthy humans, having positive values. This study proposes that circumferential strain could be an effective index for the quantitative evaluation of cardiac contractility.
