Performance of cardiovascular magnetic resonance strain in patients with acute myocarditis

To explore the value of myocardial strain derived from cardiac magnetic resonance (CMR) feature tracking in evaluating left ventricular function in acute myocarditis and its relationship with the left ventricular ejection fraction (LVEF) and late gadolinium enhancement (LGE).

A total of 115 cases of clinically suspected acute myocarditis, confirmed by CMR, were collected from two centers and divided into groups with reduced and preserved ejection fraction (EF). Fifty normal volunteers were enrolled as the control group. The myocardial strain analysis was based on feature tracking imaging (FTI).

Compared with the control group, the group with myocarditis and preserved EF showed an increased peak ejecting rate (PER), end diastolic volume (EDV), end systolic volume (ESV), stroke volume (SV), EDV index (EDVi), ESV index (ESVi), SV index (SVi) and decreased strain indices. In patient with myocarditis, the group with reduced EF showed increased EDV, ESV, LGE, LGE% and decreased strain indices compared to the group with preserved EF. EF showed good correlation with LGE, PSC, PSSRC (r>0.6). Peak strain circumferential (PSC) showed good correlation with LGE (r=0.62). The AUC of PSC was optimal to detect early left ventricular dysfunction in myocarditis patient with preserved EF using a cutoff of -19.72% (sensitivity of 68% and specificity of 88%).

Myocardial strain analysis using CMR FTI can provide information about early ventricular dysfunction in myocarditis patient with preserved EF. PSC showed best diagnostic performance, and correlated with LGE.