Natural History of Myocardial Injury and Chamber Remodeling in Acute Myocarditis

Abstract

Background: Cardiovascular magnetic resonance (CMR) imaging is commonly used to diagnose acute myocarditis. However, the natural history of CMR-based tissue markers and their association with left ventricular recovery is poorly explored. We prospectively investigated the natural history of CMR-based myocardial injury and chamber remodeling over 12 months in patients with suspected acute myocarditis. Methods: One hundred patients with suspected acute myocarditis were enrolled. All underwent CMR evaluations at baseline and 12 months, inclusive of T2 and late gadolinium enhancement. Blinded quantitative analyses compared left ventricular chamber volumes, function, myocardial edema, and necrosis at each time point using predefined criteria. The predefined primary outcomes were improvement in left ventricular ejection fraction ≥10% and improvement in the indexed left ventricular end diastolic volume ≥10% at 12 months. Results: The mean age was 39.9±14.5 years (82 male) with baseline left ventricular ejection fraction of 57.1±11.2%. A total of 72 patients (72%) showed late gadolinium enhancement at baseline with 57 (57%) having any T2 signal elevation. Left ventricular volumes and EF improved significantly at 12 months. Global late gadolinium enhancement extent dropped from 8.5±9.2% of left ventricular mass to 3.0±5.2% ( P =0.0001) with prevalence of any late gadolinium enhancement dropping to 48%. Reductions in global T2 signal ratio occurred at 12 months (1.85±0.3 to 1.56±0.2; P =0.0001) with prevalence of T2 ratio ≥2.0 dropping to 7%. Neither marker provided associations with the primary outcomes. Conclusions: In clinically suspected acute myocarditis, significant reductions in tissue injury markers occur during the first 12 months of convalescence. Neither the presence nor extent of the investigated CMR-based tissue injury markers were predictive of our pre-defined function or remodeling outcomes at 12 months in this referral population.

Prevalence of abnormal cardiovascular magnetic resonance findings in recovered patients from COVID-19: a systematic review and meta-analysis

“…LGE with T2 abnormality on CMR suggests that myocardial edema is present and the myocarditis is in the acute inflammatory phase. Consequently, the extent of LGE can diminish after recovery [38]. In contrast, LGE without a T2 abnormality after recovery from myocarditis indicates myocardial scarring or fibrosis and is associated with a poorer prognosis [9,39].…”

Management of Acute Myocarditis and Chronic Inflammatory Cardiomyopathy

“…Patients with suspected AM are generally evaluated in the emergency room due to chest pain, dyspnea, fatigue, palpitations, or syncope. 1 Based on large registries, chest pain is the most frequent symptom (85%–95% of cases), 13 – 16 , 18 followed by dyspnea (19%–49% of cases), 13 , 16 , 17 whereas syncope occurs in about 6%. 13 Fever is common (about 65%), 13 , 15 while other prodromal manifestations, such as flu-like symptoms, gastrointestinal disorders, sore throat, or respiratory tract infections, may have preceded the acute phase by a few days or weeks, with a prevalence ranging from 18% to 80%.…”

“… 52 This finding is in keeping with other studies that analyzed the changes in LGE and edema at follow-up. 16 , 53 The extent of LGE is a dynamic process in AM, mainly related to tissue edema in the acute phase that progressively vanishes over time, whereas in the late phase, LGE mainly reflects postinflammatory replacement fibrosis. 53 Persistence of LGE and disappearance of edema are markers of unfavorable prognosis compared with complete resolution or persistence of both LGE and edema.…”

Update on acute myocarditis

“…Therefore, the incidence of AM in the United States gradually increased from 95 to 144 cases per 1 million inhabitants from 2005 to 2014 [12] . Higher left ventricular (LV) ejection fraction (EF) [13][14][15] and more favorable outcomes have been observed in recent series with a CMRI-based diagnosis than in previously published series with a biopsy-based diagnosis [9 -11] . This is not surprising, considering that CMRI is hard to perform in severe acute settings (e.g.…”