Endomyocardial Biopsy in Pediatric Myocarditis and Dilated Cardiomyopathy: A Tool in Search for a Role

Endomyocardial biopsy (EMB) is a well-known diagnostic tool for the investigation and treatment of myocardial diseases and remains the gold standard for the diagnosis of myocarditis. Due to its invasiveness, with a complication rate ranging from 1 to 15%, its role in the diagnostic work-up of pediatric heart failure is not well established. The aim of this review is to define the role of EMB as diagnostic technique in the work up of children presenting with severe left ventricular dysfunction with the support of our center experience.

Histology of Cardiac Sarcoidosis with Novel Considerations Arranged upon a Pathologic Basis

Sarcoidosis is a rare disease of isolated or diffuse granulomatous inflammation. Although any organs can be affected by sarcoidosis, cardiac sarcoidosis is a fatal disorder, and it is crucial to accurately diagnose it to prevent sudden death due to dysrhythmia. Although endomyocardial biopsy is invasive and has limited sensitivity for identifying granulomas, it is the only modality that yields a definitive diagnosis of cardiac sarcoidosis. It is imperative to develop novel pathological approaches for the precise diagnosis of cardiac sarcoidosis. Here, we aimed to discuss commonly used diagnostic criteria for cardiac sarcoidosis and to summarize useful and novel histopathologic criteria of cardiac sarcoidosis. While classical histologic observations including noncaseating granulomas and multinucleated giant cells (typically Langhans type) are the most important findings, others such as microgranulomas, CD68+ CD163− pro-inflammatory (M1) macrophage accumulation, CD4/CD8 T-cell ratio, Cutibacterium acnes components, lymphangiogenesis, confluent fibrosis, and fatty infiltration may help to improve the sensitivity of endomyocardial biopsy for detecting cardiac sarcoidosis. These novel histologic findings are based on the pathology of cardiac sarcoidosis. We also discussed the principal histologic differential diagnoses of cardiac sarcoidosis, such as tuberculosis myocarditis, fungal myocarditis, giant cell myocarditis, and dilated cardiomyopathy.

COVID-19 vs. Classical Myocarditis Associated Myocardial Injury Evaluated by Cardiac Magnetic Resonance and Endomyocardial Biopsy

Background: Despite the ongoing global pandemic, the impact of COVID-19 on cardiac structure and function is still not completely understood. Myocarditis is a rare but potentially serious complication of other viral infections with variable recovery, and is, in some cases, associated with long-term cardiac remodeling and functional impairment.Aim: To assess myocardial injury in patients who recently recovered from an acute SARS-CoV-2 infection with advanced cardiac magnetic resonance imaging (CMR) and endomyocardial biopsy (EMB).Methods: In total, 32 patients with persistent cardiac symptoms after a COVID-19 infection, 22 patients with acute classic myocarditis not related to COVID-19, and 16 healthy volunteers were included in this study and underwent a comprehensive baseline CMR scan. Of these, 10 patients post COVID-19 and 13 with non-COVID-19 myocarditis underwent a follow-up scan. In 10 of the post-COVID-19 and 15 of the non-COVID-19 patients with myocarditis endomyocardial biopsy (EMB) with histological, immunohistological, and molecular analysis was performed.Results: In total, 10 (31%) patients with COVID-19 showed evidence of myocardial injury, eight (25%) presented with myocardial oedema, eight (25%) exhibited global or regional systolic left ventricular (LV) dysfunction, and nine (28%) exhibited impaired right ventricular (RV) function. However, only three (9%) of COVID-19 patients fulfilled updated CMR–Lake Louise criteria (LLC) for acute myocarditis. Regarding EMB, none of the COVID-19 patients but 87% of the non-COVID-19 patients with myocarditis presented histological findings in keeping with acute or chronic inflammation. COVID-19 patients with severe disease on the WHO scale presented with reduced biventricular longitudinal function, increased RV mass, and longer native T1 times compared with those with only mild or moderate disease.Conclusions: In our cohort, CMR and EMB findings revealed that SARS-CoV-2 infection was associated with relatively mild but variable cardiac involvement. More symptomatic COVID-19 patients and those with higher clinical care demands were more likely to exhibit chronic inflammation and impaired cardiac function compared to patients with milder forms of the disease.

Giant Cell Myocarditis Following COVID-19 Successfully Treated by Immunosuppressive Therapy

In this case report, we present a 46-year-old lady who has developed a rapidly progressive heart failure after an episode of COVID-19. The pathologic examination of her endomyocardial biopsy specimens was compatible with GCM and she was successfully treated with a combined immunosuppressive therapy regimen.

Paediatric giant cell myocarditis: a case report

A previously healthy 15-year-old teenage boy was admitted for fever and heart failure. Myocarditis was suspected, and endomyocardial biopsy revealed giant cell myocarditis. Immunosuppressive treatment was initiated, with excellent response. A plausible link to previous leptospirosis was identified. At 18-month follow-up, left ventricular function is normal. Only one other reported case of paediatric giant cell myocarditis had such a favourable outcome.

Life-threatening ventricular arrhythmia and left ventricular dysfunction associated with anti-mitochondrial antibody-positive myositis: a case report

Background Anti-mitochondrial antibody (AMA)-positive myositis is an atypical inflammatory myopathy characterized by chronic progression of muscle atrophy and cardiac involvement. Few detailed reports have shown the clinical course of the cardiac complications of AMA-positive myositis. Case summary A 47-year-old man presented with shortness of breath on exertion. Cardiac dilatation was visible on chest X-ray, and echocardiography demonstrated diffuse hypokinesis with a reduced left ventricular (LV) ejection fraction of 30%. He had mild muscle weakness in the bilateral iliopsoas muscles, and his creatine kinase (CK) and anti-mitochondrial M2 antibody levels were elevated. A liver biopsy showed no findings of primary biliary cholangitis. Coronary angiography revealed normal coronary arteries. An endomyocardial biopsy showed interstitial fibrosis and marked degeneration of the mitochondria. Fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography showed circumferential abnormal accumulation in the LV myocardium, and he was diagnosed with cardiomyopathy associated with AMA-positive myositis. Optimal drug therapy for heart failure was started, and a cardiac resynchronization therapy-defibrillator was implanted. However, his cardiac function did not improve, and he was hospitalized due to ventricular tachycardia storm 5 years after the diagnosis. Ventricular tachycardia was terminated by radiofrequency catheter ablation on the LV-anterior papillary muscle. Steroid therapy was initiated and resulted in a decreased uptake of FDG and a normalized CK level at 3 months after his second discharge; however, LV systolic dysfunction remained 1 year later. Discussion Anti-mitochondrial antibody-positive myositis can affect the myocardium and cause severe LV dysfunction and life-threatening ventricular arrhythmia over time. Keywords Anti-mitochondrial antibody-positive myositis • Endomyocardial biopsy • Ventricular tachycardia • Left ventricular dysfunction • Case report • Magnetic resonance imaging • Near-infrared spectroscopy-intravascular ultrasound