Usefulness of longitudinal systolic strain and delayed enhancement cardiac magnetic resonance in depicting risk of supraventricular arrythmias in patients with acute myocarditis and preserved left ventricular function

Background: Myocarditis have variable clinical presentation, evolution and prognosis. Aim of our study was to evaluate the value of speckle tracking echocardiography and cardiac magnetic resonance (CMR) in the short-term prediction of supraventricular arrhythmias (SVA) in patients with acute myocarditis. Methods: Seventy patients (mean age 31±14 years old) with acute myocarditis and preserved left ventricular ejection fraction (LVEF) were enrolled. Longitudinal systolic strain (LS) of the left ventricle (LV), mechanical dispersion (MD) and CMR with quantitative measurement of delayed enhancement (DE) were performed in a subset of 43 patients. Logistic regression and ROC analysis were used to identify predictors of SVA. Results: Only LS measured at sup-epicardial, mid-wall and sub-endocardial level of the apical 4-chamber view was significantly lower in patients with SVA, while MD was marginally prolonged in this setting. A value of LS > - 16.1% measured at LV mid-wall in the apical 4-chamber view (ROC-AUC.75, Sensitivity 63%, Specificity 85%) was the most accurate measure to identify patients with SVA. DE mass was also helpful with a ROC-AUC.76; a DE-Mass > 18.9 gr. had a Sensitivity 63% and a Specificity 77%, to identify patients at risk of SVA. Conclusions: Both DE mass and LS were associated with higher risk of SVA in patients with acute myocarditis and preserved LVEF. However, LS measured at the mid-wall level and limited to LV segments included in the apical 4-chamber view was the most accurate measure and did not show interaction with DE mass.