Associated factors and clinical implications of dynamic changes in late gadolinium enhancement after acute myocarditis

Abstract

Although follow-up cardiac magnetic resonance (CMR) is often performed after acute myocarditis (AM), the prognostic implications of dynamic changes in late gadolinium enhancement (LGE) are unknown. We aimed to determine the prognostic implications of dynamic LGE changes after acute AM. In a two-centre study, 204 consecutive hemodynamically stable patients (mean age 35 ± 16 years, 78.9% males) with a CMR-based diagnosis of AM were included and underwent repeat CMR 3–12 months after diagnosis. Quantitative LGE was expressed as percent of left ventricular (LV) myocardium. The primary endpoint was the occurrence of major adverse cardiac events (MACE) at median 7.3 [IQR: 5.7–8.7] years. Compared to index CMR, there was an increase in LV ejection fraction (EF) (59% vs. 55%, P < 0.001) and a decrease in LGE extent (7.6% vs. 12.0%, P < 0.001) at follow-up (mean 5.7 ± 2.6 months after index CMR). LGE persisted in 175 patients at follow-up (85.8%). LGE decreased by ≥ 50% from baseline in 94 patients (46%), by < 50% in 86 (42%) and increased in 24 (12%). Female gender (OR [95%CI] = 3.27 [1.17–9.12], P = 0.023), low baseline LVEF (OR [95%CI] = 0.93 [0.88–0.98] per %, P = 0.010) and LGE involving both septal and lateral walls (OR [95%CI] = 4.64 [1.77–12.17], P = 0.002) were independently associated with increased LGE. By multivariate Cox analysis, only baseline LVEF (HR [95%CI] = 0.94 [0.89–0.99] per %, P = 0.031), a < 50% LGE decrease (HR [95%CI] = 3.78 [1.04–10.70], P = 0.044) and an increase in LGE (HR [95%CI] = 8.35 [2.05–24.00], P = 0.003) were significantly associated with MACE. After AM, LGE persists at 6 months in the vast majority of patients but tends to decrease. A < 50% decrease or an increase in LGE are associated with MACE, indicating that follow-up CMR is relevant for risk stratification (Fig. 1).