Feature Tracking Myocardial Strain Incrementally Improves Prognostication in Myocarditis Beyond Traditional CMR Imaging Features

OBJECTIVES This study investigated the association of cardiovascular cardiac magnetic resonance (CMR) feature tracking (FT) with outcome in a patient cohort with myocarditis and evaluated the possible incremental prognostic benefit beyond clinical features and traditional CMR features. BACKGROUND CMR is used to diagnose and risk stratify patients with myocarditis. CMR-FT allows quantitative strain analysis of myocardial function; however, its prognostic benefit in myocarditis is unknown. METHODS Consecutive patients with clinically suspected myocarditis and presence of midmyocardial or epicardial late gadolinium enhancement (LGE) and/or myocardial edema in CMR were included. Clinical and CMR features were analyzed with regard to major adverse cardiovascular events (MACE) (i.e., hospitalization for heart failure, sustained ventricular tachycardia, and all-cause mortality). RESULTS Of 740 patients with clinically suspected myocarditis, 455 (61%) met our final diagnostic criteria based on CMR tissue characterization. At a median follow-up of 3.9 years, MACE occurred in 74 (16%) patients. In the univariable analysis, CMR-FT global longitudinal peak strain (GLS) was significantly associated with MACE. In a multivariable model adjusting for clinical variables (age, sex, body mass index, and acuteness of symptoms) and traditional CMR features (left ventricular ejection fraction [LVEF] and LGE extent), GLS remained independently associated with outcome (GLS hazard ratio: 1.21; 95% confidence interval: 1.08 to 1.36; p 1/4 0.001) and incrementally improved prognostication (chi-square increases from 42.6 to 79.8 to 88.5; p < 0.001). CONCLUSIONS Myocardial strain using CMR-FT provides independent and incremental prognostic value over clinical features, LVEF, and LGE in patients with myocarditis. CMR-FT may serve as a novel marker to improve risk stratification in myocarditis. (CMR Features in Patients With Suspected Myocarditis [CMRMyo]; NCT03470571) (J Am Coll Cardiol Img 2020;13:1891-901) (c) 2020 by the American College of Cardiology Foundation.