Diagnostic and Prognostic Value of Cardiac Magnetic Resonance Strain in Suspected Myocarditis With Preserved LV‐EF: A Comparison Between Patients With Negative and Positive Late Gadolinium Enhancement Findings.

Background: Late gadolinium enhancement (LGE) is absent in many patients with suspected myocarditis and preserved left ventricular ejection fraction (LV‐EF), which poses difficulties in diagnosis and risk stratification. Purpose To investigate the diagnostic and prognostic value of ventricular myocardial strain in patients with suspected myocarditis, preserved LV‐EF, and negative Lake Louis Criteria (LLC) by comparing the findings in LGE negative and LGE positive patients. Study Type: Retrospective. Population A total of 108 patients with clinically suspected myocarditis who did not satisfy LLC were divided into LGE negative (N = 65) and LGE positive (N = 43) groups. A control group consisted of 50 healthy volunteers. Field Strength/Sequence: Steady‐state free precession cine and phase‐sensitive inversion recovery segmented gradient echo LGE sequences at 3.0 T. Assessment Myocardial strain of the ventricles was evaluated by feature tracking, major adverse cardiovascular events (MACE) were assessed during follow‐up since the date of magnetic resonance examination. Statistical Tests: Independent‐samples t test, Mann–Whitney U test, receiver operating characteristic curve analysis, and Cox proportional hazard regression were performed. A P‐value <0.05 was considered statistically significant. Results: Cardiac function and myocardial deformability were impaired in all patients relative to controls. Left ventricular‐global radial (LV‐GRS), circumferential (LV‐GCS), and longitudinal (LV‐GLS) strain had diagnostic value, even in LGE negative patients (sensitivity = 0.446, 0.523, and 0.662; specificity = 0.92, 0.80, and 0.64; AUC = 0.685, 0.675, and 0.648, respectively). After a median follow‐up of 530.5 (interquartile range: 168.5–969.25) days, MACE occurred in 18 (16.67%) patients. Right ventricular GLS showed prognostic value in all patients and in LGE negative patients, both in univariable analysis (hazard ratio [HR] 1.049, 95% confidence interval [CI] 1.001–1.099 and HR 1.068, 95% CI 1.011–1.127, respectively) and in multivariable Cox survival analysis. LV‐GLS was associated with MACE in LGE positive patients in multivariable Cox survival analysis. Data Conclusion: Myocardial strain provides diagnostic and prognostic value in suspected myocarditis with preserved LV‐EF, even in the absence of LGE. Level of Evidence: 3 Technical Efficacy: 2 [ABSTRACT FROM AUTHOR]