Early and Follow-up CMR Features of Acute Biventricular Myocarditis.

A 17-year-old male had fever, cough, rhinorrhea for 10 days. He suddenly complained of chest pain; troponine raised to 31 ng/mL (normal 0.15 ng/mL); electrocardiogram showed concave inferolateral ST elevation (Figure 1A). Left ventricular (LV) inferolateral hypokinesia was displayed at transthoracic echocardiography (TTE). Cardiovascular magnetic resonance (MR) confirmed TTE patterns and showed normal LV ejection fraction (LVEF; 56%) and right ventricular ejection fraction (RVEF; 54%), with normal LV strain values at feature tracking but altered right ventricular (RV) global longitudinal strain (GLS, −18.9%) and global radial strain (GRS, 9.5%) (Figure 1B, Movie 1), and demonstrated diffuse late gadolinium enhancement (LGE) hypersignals affecting the myocardium of both ventricles (Figure 1C and D).

Figure 1

Electrocardiogram recorded during chest pain shows widespread ST-segment elevation (A). RV GLS and GRS measurements in a 4-chamber plane at initial presentation (B). Late gadolinium enhancement MR view in a four chamber (C) and short axis (D) orientation showing multiple foci of inflammation/necrosis of the free RV wall, septum and lateral LV wall. Follow-up RV GLS and GRS measurements (E) and LGE MR at 1 year, same orientations (F, G). RV involvement has quite completely resolved whereas LV LGE remains present.

GLS: global longitudinal strain, GRS: global radial strain, LGE: late gadolinium enhancement, LV: left ventricular, MR: magnetic resonance, RV: right ventricular.

LVEF and RVEF remained normal at follow-up (65% and 57% respectively) as well as LV GLS and GRS (−20.9% and 65.7%), whereas RV GLS and GRS returned to normal values (−27.6% and 86.6%) with less disorganized features than on initial MR imaging (MRI; Figure 1E, Movie 2). RV LGE had quite completely resolved whereas patchy LV LGE remained present (Figure 1F and G). TTE did not reveal any RV abnormality at presentation and follow-up (Movie 3).

RV dysfunction is frequent during the course of acute myocarditis.1) RV involvement is seldom recognized at cardiac imaging, despite as frequent as 17.8% in acute myocarditis, with 2% exclusive RV involvement.1) MRI1)2)3) allows for depiction of RV involvement in acute myocarditis, with or without LV injury. Lake Louise criteria are difficult to apply at the level of the right ventricle; LGE, along with T2 and T1 mapping4) and strain using feature tracking2) are the cornerstones of multiparametric MR acquisitions. As for LV myocarditis, MR follow-up is of paramount importance to monitor complete RV resolution or disease persistence.