Cardiovascular magnetic resonance predictors of clinical outcome in patients with suspected acute myocarditis

Abstract

Background: The natural history of acute myocarditis (AM) remains highly variable and predictors of outcome are largely unknown. The objectives were to determine the potential value of various cardiovascular magnetic resonance (CMR) parameters for the prediction of adverse long-term outcome in patients presenting with suspected AM.

Methods: In a single-centre longitudinal prospective study, 203 routine consecutive patients with an initial CMR-based diagnosis of AM (typical Late Gadolinium Enhancement, LGE) were followed over a mean period of 18.9 ± 8.2 months. Various CMR parameters were evaluated as potential predictors of outcome. The primary endpoint was defined as the occurrence of at least one of the combined Major Adverse Clinical Events (MACE) (cardiac death or aborted sudden cardiac death, cardiac transplantation, sustained documented ventricular tachycardia, heart failure, recurrence of acute myocarditis, and the need for hospitalization for cardiac causes).

Results: The vast majority of patients (N = 143,70 %) presented with chest pain, mild to moderate troponin elevation and ST-segment or T wave abnormalities. Various CMR parameters were evaluated on initial CMR performed 3 ± 2 days after acute clinical presentation (LV functional parameters, presence/extent of edema on T2 CMR, and extent of late gadolinium enhancement lesions). Out of the 203 patients, 22 experienced at least one major cardiovascular event (10.8 %) during follow-up for a total of 31 major cardiovascular events. Among all CMR parameters, the only independent CMR predictor of adverse clinical outcome by multivariate analysis was an initial alteration of LVEF (p = 0.04).

Conclusions: In routine consecutive patients without severe hemodynamic compromise and a CMR-based diagnosis of AM, various CMR parameters such as the presence and extent of myocardial edema and the extent of late gadolinium-enhanced LV myocardial lesions were not predictive of outcome. The only independent CMR predictor of adverse clinical outcome was an initial alteration of LVEF.

Fig. 1

CMR data of a 25 year-old male performed at day 1 after the onset of an acute coronary-like syndrome (chest pain, ST segment alterations, mild troponin elevation). Black blood T2-weighted STIR CMR indicates the presence of segmental diffuse myocardial edema of the LV posterior and lateral walls representing 23 % of LV mass (top panel, arrows). Late gadolinium-enhanced CMR shows diffuse subepicardial nodular lesions in the posterolateral and lateral walls of the LV (11 % of LV mass) indicative of acute myocarditis (mid panel, arrows). Cine-MR at day 1 and 6 months (bottom panel) showed normal systolic global and segmental LV function (LV end-diastolic volume index 71 ml/m², LV ejection fraction 61 %; 69 ml/m² and 63 %, respectively). The patient did well and had no MACE during follow-up

Fig. 2

CMR data findings of a 56-year-old male performed at day 2 after the onset of an acute coronary-like syndrome (chest pain, ST segment alterations, mild troponin elevation). Black blood T2-weighted STIR CMR indicates the presence of limited subepicardial hypersignal in the mid portion of the posterolateral and lateral LV walls, indicative of small foci of myocardial edema (top panel, arrows, 4 % LV mass). Late gadolinium-enhanced CMR shows limited subepicardial nodular lesions in the mid portion of the posterolateral and lateral LV walls (mid panel, arrows, 6 % LV mass), indicative of acute myocarditis. Cine-MR at day 2 and 6 months (bottom panel) showed altered systolic global LV function (LV end-diastolic volume index 83 ml/m², LV ejection fraction 45 %; 101 ml/m² and 36 %, respectively). Despite optimal medical therapy, the patient suffered NYHA Class III heart failure during follow-up with diffuse LV hypokinesia predominant in the lateral wall