Post-COVID-19 Vaccination Myocarditis: A Histopathologic Study on a Monocentric Series of Six Cases.

Many reports on the development of myocarditis following coronavirus disease 2019 (COVID-19) vaccination (PCVM) have emerged. However, only a few case studies have investigated endomyocardial biopsy (EMB) results. This study describes the clinicopathologic features of PCVM. We surveyed all hospitalized patients in a single university hospital in Korea and identified six cases of PCVM. All six patients underwent EMB, five of whom were men aged 15-85 years. All patients developed cardiac dysfunction. Among these patients, two had mild disease without sequelae, whereas the other four had dilated cardiomyopathy with depressed cardiac function. All six cases demonstrated lymphohistiocytic myocarditis. Two of our cases fulfilled the criterion of CD3+ T lymphocytes > 7 cells/mm2 (Case nos. 3 and 6), while the remaining four cases did not fulfill the Dallas criteria. In conclusion, most PCVM cases showed mild degree inflammation histopathologically, and some cases could not fulfill the Dallas criteria and were classified as borderline myocarditis.

Pathophysiology of Heart Failure with Preserved Ejection Fraction.

Heart failure with preserved ejection fraction (HFpEF) is a major public health problem that affects half of all patients with HF. It is rising in prevalence, is associated with high morbidity and mortality, and has very few effective treatments. HFpEF is currently understood as a heterogeneous syndrome originating from the interplay of cardiac and extracardiac abnormalities. The most important pathophysiology in patients with HFpEF is diastolic dysfunction, which presents with impairments in relaxation or increases in chamber stiffness that lead to an increase in left ventricular filling pressures at rest or during exercise that causes dyspnea.