Value of left ventricular myocardial strain derived from cardiac magnetic resonance tissue tracking on differentiating constrictive pericarditis from restrictive cardiomyopathy

Objective: To compare left ventricular myocardial mechanics detected by cardiac magnetic resonance tissue tracking(CMR-TT) between patients with constrictive pericarditis(CP) and restrictive cardiomyopathy(RCM),and see if those can be used to differentiate CP from RCM patients. Methods: A total of 23 patients with CP, 20 patients with RCM, who hospitalized in Beijing Anzhen Hospital from January 2014 to April 2019 were included in this study and 25 healthy subjects served as control group, all subjects underwent cardiac magnetic resonance examination. Myocardial mechanics were evaluated by 2-dimensional(2D) and 3-dimensional(3D) CMR-TT in terms of global longitudinal strain(GLS), circumferential strain(GCS), radial strain(GRS) and the lateral wall strain to septal wall strain ratio(lateral/septal ratio) of basal, mid-cavity and apical. The diagnostic area under the receiver operating characteristic curve (ROC) was evaluated for differentiating CP from RCM. Results: Age, sex and heart rate were similar between CP and RCM patients(all P>0.05). 2D-GLS, 3D-GLS, GCS and GRS in CP and RCM groups were significantly lower than those in normal control group(all P 0.05). Compared with RCM, the circumferential and radial lateral/septal ratios of the basal were significantly lower in CP group than in RCM group(both P<0.05), AUC=0.737(sensitivity 70%, specificity 83%) and 0.737 (sensitivity 60%, specificity 87%), respectively. The left ventricular myocardial mechanics strain curve of the CP,RCM and normal control were different. The CP patients presented as " rapidly down-a platform" form, the RCM presented as "slowly down" form, and normal control presented as "rapidly down" form. Conclusion: Evaluating the differences in the diastolic process of left ventricular myocardium and left ventricular myocardial mechanics strain curve is helpful to differentiate CP from RCM patients.