Abstract 11885: Optimal Timing and Prognostic Value of Follow-Up Cardiac Magnetic Resonance in Patients With Acute Myocarditis

Abstract

Background: cardiac magnetic resonance (CMR) is central for diagnosis, follow up and prognostic stratification of acute myocarditis. Late gadolinium enhancement (LGE) extent and persistence at follow-up represents a negative prognostic marker. However, time course of oedema resolution and LGE stabilization and optimal timing to repeat CMR are unclear. Hypothesis: we assessed time course of oedema and LGE evolution to identify optimal timing to repeat CMR in acute myocarditis. Methods: 36 acute myocarditis patients (35M, 28,8±10,3 years) underwent CMR at clinical presentation (CMR-1), after 3 months (CMR-2) and after 12-months (CMR-3). We assessed oedema and LGE and measured left ventricular ejection fraction (LVEF) and indexed mass (iLVM). After CMR-3 all patients were followed up yearly with clinical evaluation, Holter ECG and echocardiography. Results: all patients had oedema and LGE at CMR-1. At CMR-2 significant reduction of oedema (T2 positive segments 0,4±0,9 vs 4,1±3,2 p<0.0001) and LGE (4,3±3,9 vs 7,5±5,6 p<0.0001) was observed compared to CMR-1, with improvement of LVEF (62,7±5,6 vs 58,5±12,2% p<0.05) and reduction of iLVM (71,2±13,7 vs 78,1±15,2 g/m2 p<0.0001). At CMR-3 no further LGE reduction nor LVEF and iLVM improvement were observed. At 60±23-months follow-up, no major cardiovascular events nor myocarditis recurrences occurred. At Holter ECG 8/36 patients (28%) had non-sustained ventricular tachycardias. Ventricular arrhythmias were associated with lower LVEF at CMR-1 (46.25±19.55 vs 62.00±6.02 p=0.001) and higher LGE at CMR-2 (10.19±8.01 vs 3.60±3.14 p=0.007) but not with LGE at CMR-1 (10.05±7.14 vs 6.80±4.65 p=0.13). Conclusions: most patients with acute myocarditis present oedema resolution and LGE stabilization after 3 months. LVEF at baseline and LGE extension at second CMR correlates with ventricular arrhythmias persistence. Our findings redefine follow up and imaging-based prognostic stratification of acute myocarditis.