Between 2006 and 2015, 112 consecutive patients with CMRbased diagnosis of acute myocarditis according to the Louise-Lake criteria were identified in our institution. Of them, 88 were available for clinical follow-up and represent our studied population. Patients were divided into Infarct-like, (n=48) (association of acute chest pain, raised Troponin and STElevation) and non-infarct-like, (n=40) with any other presentation. The composite primary endpoint of Major CardioVascular Events included: all-cause mortality, cardiac mortality, recurrence of myocarditis, heart failure or sustained ventricular tachycardia.
During follow-up, 21 patients (24%) experienced MACE and the infarct-like patients were significantly more at risk for MACE than group B patients (HR 2.4, 95% CI [1.01 – 5.80] p=0.04). Patients of the Group A exhibited in particular a higher risk of sustained ventricular tachycardia and recurrence of myocarditis as compared with group B patients (p=0.03). Infarct-like patients had lower CMR-derived left (p=0.03) and right (p=0.001) ventricular ejection fractions, and exhibited larger areas of late Gadolinium enhancement (LGE) (p=0.001) as compared with group B patients. In multivariate analysis, both initial NYHA functional class>II and LGE mass were independent predictors for long-term MACE occurrence after acute myocarditis (HR 5.8 and 1.07 per g respectively, p=0.007). Moreover, a threshold of LGE mass>17g provided a high discrimination for MACE occurrence (AUC of 0.81).
The infarct-like pattern of acute myocarditis is associated with MACE, especially sustained ventricular tachycardia and recurrence of myocarditis.
The author hereby declares no conflict of interest