Park JJ, et al. Int J Heart Fail. 2021 Oct;3(4):224-236. https://doi.org/10.36628/ijhf.2021.0023

Kim MS, et al. Korean Circ J. 2017 Sep;47(5):555-643. https://doi.org/10.4070/kcj.2017.0009

A comprehensive nationwide study on the incidence and outcomes of COVID-19 vaccination-related myocarditis (VRM) is in need. Among 44 276 704 individuals with at least 1 dose of COVID-19 vaccination, the incidence and clinical courses of VRM cases confirmed by the Expert Adjudication Committee of the Korea Disease Control and Prevention Agency were analyzed. COVID-19 VRM was confirmed in 480 cases (1.08 cases per 100 000 persons). Vaccination-related myocarditis incidence was significantly higher in men than in women (1.35 vs. 0.82 per 100 000 persons, P < 0.001) and in mRNA vaccines than in other vaccines (1.46 vs. 0.14 per 100 000 persons, P < 0.001). Vaccination-related myocarditis incidence was highest in males between the ages of 12 and 17 years (5.29 cases per 100 000 persons) and lowest in females over 70 years (0.16 cases per 100 000 persons). Severe VRM was identified in 95 cases (19.8% of total VRM, 0.22 per 100 000 vaccinated persons), 85 intensive care unit admission (17.7%), 36 fulminant myocarditis (7.5%), 21 extracorporeal membrane oxygenation therapy (4.4%), 21 deaths (4.4%), and 1 heart transplantation (0.2%). Eight out of 21 deaths were sudden cardiac death (SCD) attributable to VRM proved by an autopsy, and all cases of SCD attributable to VRM were aged under 45 years and received mRNA vaccines. Although COVID-19 VRM was rare and showed relatively favorable clinical courses, severe VRM was found in 19.8% of all VRM cases. Moreover, SCD should be closely monitored as a potentially fatal complication of COVID-19 vaccination. Study flowchart and summary of the percentage of patients with adverse outcomes among 480 cases of COVID-19 vaccination-related myocarditis. VRM, vaccine-related myocarditis; SCD, sudden cardiac death; ICU, intensive care unit; ECMO, extracorporeal membrane oxygenation

Youn JC, et al. Int J Heart Fail. 2023 Apr;5:e9. https://doi.org/10.36628/ijhf.2023.0011

Sun BJ, et al. J Cardiovasc Imaging. 2019 Sep;28:e42. https://doi.org/10.4250/jcvi.2020.0043

It has been reported that left ventricular (LV) myocardial strain and late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) imaging have prognostic value in patients with heart failure (HF). However, previous studies included patients with various systolic functions. This study aimed to investigate the prognostic value of LV myocardial strain and LGE on CMR imaging in patients with idiopathic dilated cardiomyopathy (DCM) with reduced ejection fraction (EF < 40%). From a prospectively followed cohort who underwent CMR between November 2008 and December 2015, subjects with LV EF < 40% and a diagnosis of idiopathic DCM were eligible for this study. The CMR images were analyzed for LV and right ventricular (RV) function, presence and extent of LGE, and LV myocardial strain. The primary outcome was a composite of all-cause death and heart transplantation. The secondary outcome was hospitalization for HF. A total of 172 patients were included, in whom mean LV EF was 23.7 ± 7.9% (EF 30–40% n = 47; EF < 30% n = 125). During a median follow-up of 47 months, the primary outcome occurred in 43 patients (16 heart transplantations, 29 all-cause deaths), and there were 41 hospitalizations for HF. Univariate Cox proportional hazard regression analysis showed that mean arterial pressure, serum sodium concentration, log of plasma NT-proBNP level, and presence of LGE (HR 2.277, 95% CI: 1.221–4.246) were significantly associated with the primary outcome. However, LV strain had no significant association (HR 1.048, 95% CI: 0.945–1.163). Multivariable analysis showed that presence of LGE (HR 4.73, 95% CI: 1.11–20.12) and serum sodium (HR 0.823, 95% CI: 0.762–0.887) were independently associated with the primary outcome. LGE in CMR imaging was a good predictor of adverse outcomes for patients with idiopathic DCM and reduced EF. Identification of LGE could thus improve risk stratification in high-risk patients. LV strain had no significant prognostic value in patients with moderate to severe systolic dysfunction.