Myocarditis: a primer for intensivists

Long-term prognostic performance of cardiac magnetic resonance imaging markers versus complicated clinical presentation after an acute myocarditis

BACKGROUND

Identifying markers associated with adverse events after acute myocarditis (AM) is relevant to plan follow-up. We assessed the prognostic performance of previously described cardiac magnetic resonance imaging (CMRI) markers and their combination: septal late gadolinium enhancement (LGE) localization and left ventricular ejection fraction (LVEF) < 50 % on baseline CMRI versus complicated clinical presentation (CCP: the presence of sustained ventricular tachycardia, or LVEF<50 % on the first echocardiogram or fulminant presentation).

METHODS

We retrospectively assessed 248 AM patients (median age of 34 years, 87.1 % male) from 6 hospitals with onset of cardiac symptoms<30 days, increased troponin, and CMRI/histology consistent with myocarditis to identify those at risk of major cardiac events (cardiac death, heart transplantation, aborted sudden cardiac death, sustained ventricular tachycardia, or heart failure hospitalization).

RESULTS

Thirteen patients (5.2 %) experienced at least one major cardiac event after a median follow-up of 4.7 years with a significant hazard ratio of 35.8 for CCP vs. 9.2 for septal LGE vs. 12.4 for LVEF<50 % on baseline CMRI (p = 0.001). CCP had the best c-index to identify patients with events: 0.836 vs. 0.786 for septal LGE and 0.762 for LVEF<50 %, while the combination of CCP plus LVEF<50 % or septal LGE has the highest c-index of 0.866. All 3 markers had high negative predictive value (NPV) of ≥0.98.

CONCLUSIONS

Major cardiac events after an AM are relatively low, and CCP, septal LGE, and LVEF<50 % are significantly associated with events. These markers have especially high NPV to identify patients without events after an AM. These observations can help clinicians to monitor the patients after an AM.

Fulminant Myocarditis Temporally Associated with COVID-19 Vaccination

PURPOSE OF REVIEW

Coronavirus disease-2019 (COVID-19) vaccines have been related to rare cases of acute myocarditis, occurring between 1 in 10,000 and 1 in 100,000 individuals, approximately. Incidence of COVID-19 vaccine-associated myocarditis varies with age, sex, and type of vaccine. Although most patients with acute myocarditis temporally associated with COVID-19 vaccines have an uneventful course, a small subpopulation presents with cardiogenic shock (termed fulminant myocarditis [FM]). This review explored the prevalence, clinical presentation, management, and prognosis of COVID-19 vaccine-associated acute myocarditis, specifically focusing on FM and comparing patients with fulminant versus non-fulminant myocarditis.

RECENT FINDINGS

Cases of FM represent about 2-4% (0 to 7.5%) of COVID-19 vaccine-associated acute myocarditis cases, and mortality is around 1%, ranging between 0 and 4.4%. First, we identified 40 cases of FM up to February 2023 with sufficient granular data from case reports and case series of COVID-19 vaccine-associated acute myocarditis that occurred within 30 days from the last vaccine injection. This population was compared with 294 cases of non-fulminant acute myocarditis identified in the literature during a similar time. Patients with FM were older (48 vs. 27 years), had a larger proportion of women (58% vs. 9%), and mainly occurred after the first shot compared with non-fulminant cases (58% vs. 16%). The reported mortality was 27% (11 out of 40), in line with non-vaccine-associated fulminant myocarditis. These data were in agreement with 36 cases of FM from a large Korean registry. Herein, we reviewed the clinical features, imaging results, and histological findings of COVID-19 vaccine-associated fulminant myocarditis. In conclusion, COVID-19 vaccine-associated FM differs from non-fulminant forms, suggesting potential specific mechanisms in these rare and severe forms. Mortality in vaccine-associated FM remains high, in line with other forms of FM.

The role of genetic testing in suspected fulminant myocarditis: A case report

ACM is a rare hereditary heart disease characterized by a progressive fibro-fatty replacement of the myocardium that can affect either the right or the left ventricle or both. It is mainly caused by variants in the desmosome genes with autosomal dominant transmission and incomplete penetrance. The disease shows a wide spectrum of clinical manifestations, including ventricular arrhythmias, HF and myocarditis. The latter is considered a 'hot phase' in the natural history of the disease and must therefore be distinguished from the isolated AM, which is frequently due to viral infections. Our case report is an example of how an AM, as the first manifestation of the disease, helped to reach a diagnosis of ACM through the genetic analysis. In fact, the multi-parametric investigation, which also included CMR and EMB, revealed controversial aspects that led us to perform the genetic test. The latter revealed a heterozygous pathogenic variant in the PKP2 that was considered definitive proof of ACM.