Regional heterogeneity of function in nonischemic dilated cardiomyopathy

Objective: To quantify regional three-dimensional (3D) motion and myocardia l strain using magnetic resonance (MR) tissue tagging in patients with non- ischemic dilated cardiomyopathy (DCM). Methods: MR grid tagged images were obtained in multiple short- and long-axis planes in thirteen DCM patients. Regional 3D displacements and strains were calculated with the aid of a fin ite element model. Five of the patients were also imaged after LV volume re duction by partial left ventriculectomy (PLV), combined with mitral and tri cuspid valve repair. Results: DCM patients showed consistent, marked region al heterogeneity. Systolic lengthening occurred in the septum in both circu mferential (%S-C -5+/-7%) and longitudinal (%S-L -2+/-5%) shortening compon ents (negative values indicating lengthening). In contrast the lateral wall showed relatively normal systolic shortening (%S-C 12+/-6% and %S-L 6+/-5% , P<0.001 lateral vs. septal walls). A geometric estimate of regional stres s was correlated with shortening on a regional basis, but could not account for the differences in shortening between regions. In the five patients im aged post-PLV, septal function recovered (%S-C 9+/-5%,%S-L 6+/-5%, P<0.02 p re vs. post) with normalization of wall stress, whereas lateral wall shorte ning was reduced (%S-C 7+/-6%,%S-L 3+/-3%, P<0.02 pre vs, post) around the site of surgical resection. Conclusions: A consistent pattern of regional h eterogeneity of myocardial strain was seen in all patients. Reduced functio n may be related to increased wall stress, since recovery of septal functio n is possible after PLV. However, simple geometric stress determinants are not sufficient to explain the functional heterogeneity observed. (C) 2001 E lsevier Science B.V. All rights reserved.