Acute lymphocytic myocarditis presenting as complete heart block in an adult: a case report

BACKGROUND

Complete heart block (CHB) as a first presentation of acute viral myocarditis is a rare occurrence associated with increased morbidity and mortality. In such cases, an endomyocardial biopsy is recommended to make a clear histological diagnosis aiding to differentiate from other possible conditions such as sarcoiditic myocarditis, giant cell myocarditis, and eosinophilic myocarditis. Insertion of a permanent pacemaker may be considered on a case-to-case basis.

CASE PRESENTATION

A previously healthy 21-year-old female presented to the emergency department after having suffered two episodes of syncope on a background of a few days' history of myalgias, chills, and rigors. Electrocardiogram showed high-grade Mobitz II block with intermittent periods of CHB. A bedside echocardiogram upon admission demonstrated normal biventricular systolic function. Given the patient's unstable haemodynamic status and lack of obvious reversible causes for the CHB, a permanent dual-chamber pacemaker was inserted urgently. Initial blood investigations indicated an ongoing inflammatory process highlighting the possibility of myocarditis as a cause of the CHB. Therefore, a troponin level was taken and was noted to be elevated confirming the suspicion of myocarditis. The left ventricular ejection fraction (LVEF) decreased over the following days to approximately 20%, clinically resulting in pulmonary oedema and acute shortness of breath. The patient required aggressive intravenous diuresis and anti-heart failure medication. An endomyocardial biopsy (EMB) confirmed the diagnosis of lymphocytic myocarditis. The patient's condition improved secondary to an improvement in LVEF and resolution of the heart block. A cardiac magnetic resonance (CMR) imaging performed 6 weeks from admission reported an improved LVEF of 51% with no late gadolinium enhancement (LGE). Based on the reassuring CMR findings and the resolution of CHB on follow-up pacemaker checks, it was deemed safe to explant the pacemaker.

CONCLUSIONS

Acute myocarditis may be complicated with high-degree AV block and cardiogenic shock necessitating close observation in a critical care unit. A permanent pacemaker may provide atrio-ventricular synchrony which helps stabilise the patient's condition and protect from a prolonged period of heart block. Early myocardial fibrosis on EMB and degree of LGE on CMR are indicators of persistent atrioventricular block. Guideline-directed treatment of heart failure is essential.

A case of lymphocytic myocarditis in a patient treated with an immune checkpoint inhibitor, a recent class of chemotherapy agents

Chemotherapy-associated cardiotoxicity is a common adverse event. Immune checkpoint inhibitors (ICI) - a new class of monoclonal antibodies - have revolutionized the management of various diseases. Their use is expected to increase in the near future and their cardiac side effects have been increasingly recognized. CLINICAL CASE: We describe a case of a 67-year-old female patient with urothelial carcinoma undergoing treatment with pembrolizumab who presented to the emergency department with progressive fatigue, retrosternal pain and palpitations for three days. On admission she was diagnosed with acute heart failure (HF). The electrocardiogram revealed a right bundle branch block and ventricular bigeminy. Blood tests showed elevated troponin I, while transthoracic echocardiography revealed severe left ventricular dysfunction. Coronary angiography excluded coronary artery disease. Cardiac magnetic resonance revealed moderate left ventricular dysfunction and late gadolinium enhancement typical of myocarditis. Endomyocardial biopsy confirmed the diagnosis of lymphocytic myocarditis. In the first 48h of hospitalization, she developed transient complete AV block. Corticoid and HF therapy were initiated, leading to symptom improvement and disappearance of the rhythm disturbances. She was discharged on the 12th day, maintaining moderate LV dysfunction, which improved only mildly at a subsequent outpatient assessment. She died suddenly 35 days after discharge. CONCLUSION: Lymphocytic myocarditis is a serious cardiac side effect of ICI therapy. Pembrolizumab is increasingly used, so it is important to be aware of its effects, in order to perform an early diagnosis and provide adequate treatment. Corticosteroid therapy seems to be crucial in preventing disease progression and enabling ventricular remodeling.

Lymphocytic myocarditis presenting as acute myocardial infarction: a case report and review of the literature

We report a case that presented as acute myocardial infarction (AMI) caused by lymphocytic myocarditis (LM), and explore the relationship between AMI and LM. We also performed a literature search to identify publications that previously reported LM-associated myocardial infarction. Coronary angiography of our patient revealed normal coronary arteries. However, a perfusion-metabolism mismatch in the apex and mid-inferior walls supported the diagnosis of AMI, and right ventricular septal endomyocardial biopsy showed LM. Extensive viral serological tests were negative for an infectious etiology. Immunosuppressive therapy may be beneficial in patients with high-risk myocarditis who are pathologically confirmed to be virus-negative.

Fatal lymphocytic cardiac damage in coronavirus disease 2019 (COVID-19): autopsy reveals a ferroptosis signature

AIMS

Cardiovascular complications, including myocarditis, are observed in coronavirus disease 2019 (COVID-19). Major cardiac involvement is a potentially lethal feature in severe cases. We sought to describe the underlying pathophysiological mechanism in COVID-19 lethal cardiogenic shock.

METHODS AND RESULTS

We report on a 48-year-old male COVID-19 patient with cardiogenic shock; despite extracorporeal life support, dialysis, and massive pharmacological support, this rescue therapy was not successful. Severe acute respiratory syndrome coronavirus 2 RNA was detected at autopsy in the lungs and myocardium. Histopathological examination revealed diffuse alveolar damage, proliferation of type II pneumocytes, lymphocytes in the lung interstitium, and pulmonary microemboli. Moreover, patchy muscular, sometimes perivascular, interstitial mononuclear inflammatory infiltrates, dominated by lymphocytes, were seen in the cardiac tissue. The lymphocytes 'interlocked' the myocytes, resulting in myocyte degeneration and necrosis. Predominantly, T-cell lymphocytes with a CD4:CD8 ratio of 1.7 infiltrated the interstitial myocardium, reflecting true myocarditis. The myocardial tissue was examined for markers of ferroptosis, an iron-catalysed form of regulated cell death that occurs through excessive peroxidation of polyunsaturated fatty acids. Immunohistochemical staining with E06, a monoclonal antibody binding to oxidized phosphatidylcholine (reflecting lipid peroxidation during ferroptosis), was positive in morphologically degenerating and necrotic cardiomyocytes adjacent to the infiltrate of lymphocytes, near arteries, in the epicardium and myocardium. A similar ferroptosis signature was present in the myocardium of a COVID-19 subject without myocarditis. In a case of sudden death due to viral myocarditis of unknown aetiology, however, immunohistochemical staining with E06 was negative. The renal proximal tubuli stained positively for E06 and also hydroxynonenal (4-HNE), a reactive breakdown product of the lipid peroxides that execute ferroptosis. In the case of myocarditis of other aetiology, the renal tissue displayed no positivity for E06 or 4-HNE.

CONCLUSIONS

The findings in this case are unique as this is the first report on accumulated oxidized phospholipids (or their breakdown products) in myocardial and renal tissue in COVID-19. This highlights ferroptosis, proposed to detrimentally contribute to some forms of ischaemia-reperfusion injury, as a detrimental factor in COVID-19 cardiac damage and multiple organ failure.

Viral presence-guided immunomodulation in lymphocytic myocarditis: an update

Latest statements from European and American societies recommend to rule out viral presence in endomyocardial biopsy (EMB) via polymerase chain reaction (PCR) analysis before starting immunosuppression or immunomodulation in acute lymphocytic myocarditis presenting with life‐threatening scenarios. However, recommendations in myocarditis are mostly based on heterogeneous studies enrolling patients with inflammatory cardiomyopathies and established heart failure rather than acute myocarditis. Thus, definitive evidence of a survival benefit from immunomodulation guided by viral presence is currently lacking. Finally, distinguishing innocent bystanders from causative agents among EMB‐detected viruses remain challenging and a major goal to achieve in the near future. Therefore, considerable divergence remains between official recommendations and clinical practice, including the possibility of starting immunosuppressive therapy empirically, without knowing viral PCR results. This review systematically discusses the unsolved issues of immunomodulation guided by viral presence in acute lymphocytic myocarditis, namely (i) virus epidemiology and prognosis, (ii) variability of viral presence rates, (iii) the role of potential viral bystander findings, and (iv) the main results of immunosuppression controlled trials in lymphocytic myocarditis. Furthermore, a practical approach for the critical use of viral presence analysis in guiding immunomodulation is provided, highlighting its importance before starting immunosuppression or immunomodulation. Future, multicentre studies are needed to address specific scenarios such as fulminant lymphocytic myocarditis and a virus‐tailored management as for parvovirus B19.

A case report of isolated right ventricular lymphocytic myocarditis

Background

Lymphocytic myocarditis is an uncommon condition with a variety of clinical presentations. Isolated involvement of the right ventricle (RV) is very rare. We present a case of a young woman who developed right ventricular dysfunction and arrhythmias as a consequence of this condition, which appeared to be chronic at diagnosis.

Case summary

A 26-year-old lady was admitted to hospital following routine echocardiography, requested for screening of pulmonary hypertension in the context of known hypersensitivity pneumonitis. This echocardiogram demonstrated severe right ventricular dilatation and impairment. She was also experiencing atrial fibrillation and non-sustained, symptomatic episodes of ventricular tachycardia. Endomyocardial biopsy revealed lymphocytic myocarditis. She was managed with azathioprine and prednisone, as well as sotalol and apixaban for her atrial fibrillation, and has had no complications in the 12 months since discharge.

Discussion

Lymphocytic myocarditis isolated to the RV has only been reported in two previous cases, both of which were acute, dramatic presentations. This is the first report of a chronic example of this disease process. Due to her intercurrent immunosuppression, this patient may have been pre-disposed to the condition either by re-activation of a latent viral infection or partial treatment of a true autoimmune lymphocytic myocarditis.

An unusual case of severe myocarditis in a genetic cardiomyopathy: a case report

Background

Myocarditis is an inflammatory disease of the myocardium caused by infectious pathogens, immune-mediated conditions, or toxic agents. This report explores a rare case of severe myocarditis occurring in an inherited cardiomyopathy.

Case summary

A 24-year-old female patient presented with progressing dyspnoea and chest discomfort. Echocardiography and cardiac magnetic resonance imaging revealed dilated cardiomyopathy (DCM) with severe biventricular dysfunction [left ventricle ejection fraction (LV-EF) 10%]. Myocardial inflammation was suspected due to extensive subendocardial to transmural late gadolinium enhancement. Endomyocardial biopsy (EMB) showed severe chronic lymphocytic myocarditis. As inflammatory DCM was assumed, immunosuppressive therapy with prednisolone was initiated in addition to standard heart failure therapy. Endomyocardial biopsy after 3 months showed resolving inflammation. However, a marked architectural disarray observed in all biopsies raised the suspicion of an inherited cardiomyopathy. Genetic testing revealed a de novo mutation with effect on splicing of lysosome-associated membrane protein 2, as found in Danon disease. Periodic acid–Schiff (PAS) staining confirmed a glycogen storage disorder. Immunosuppressive therapy was intensified due to reactivation of myocardial inflammation and led to improvement of LV-EF and to significant symptom relief over a 16-month follow-up period.

Discussion

This is the first report of Danon disease initially presenting as a severe myocarditis. It illustrates the clinical value of EMB for diagnosis and immunosuppressive therapy monitoring in chronic myocarditis. Increasing evidence suggests that myocardial inflammation may modify disease progression and prognosis in inherited cardiomyopathies. The causal role of cardiac protein mutations in the pathophysiology of myocarditis remains to be determined.

Lymphocytic myocarditis occurs with myocardial infarction and coincides with increased inflammation, hemorrhage and instability in coronary artery atherosclerotic plaques

OBJECTIVE

Although lymphocytic myocarditis (LM) clinically can mimic myocardial infarction (MI), they are regarded as distinct clinical entities. However, we observed a high prevalence (32%) of recent MI in patients diagnosed post-mortem with LM. To investigate if LM changes coronary atherosclerotic plaque, we analyzed in autopsied hearts the inflammatory infiltrate and stability in coronary atherosclerotic lesions in patients with LM and/or MI.

METHODS

The three main coronary arteries were isolated at autopsy of patients with LM, with MI of 3-6h old, with LM and MI of 3-6h old (LM+MI) and controls. In tissue sections of atherosclerotic plaque-containing coronary segments inflammatory infiltration, plaque stability, intraplaque hemorrhage and thrombi were determined via (immuno)histological criteria.

RESULTS

In tissue sections of those coronary segments the inflammatory infiltrate was found to be significantly increased in patients with LM, LM+MI and MI compared with controls. This inflammatory infiltrate consisted predominantly of macrophages and neutrophils in patients with only LM or MI, of lymphocytes in LM+MI and MI patients and of mast cells in LM+MI patients. Moreover, in LM+MI and MI patients this coincided with an increase of unstable plaques and thrombi. Finally, LM and especially MI and LM+MI patients showed significantly increased intraplaque hemorrhage.

CONCLUSIONS

This study demonstrates prevalent co-occurrence of LM with a very recent MI at autopsy. Moreover, LM was associated with remodeling and inflammation of atherosclerotic plaques indicative of plaque destabilization pointing to coronary spasm, suggesting that preexistent LM, or its causes, may facilitate the development of MI.

CD45 is a more sensitive marker than CD3 to diagnose lymphocytic myocarditis in the endomyocardium

To diagnose lymphocytic myocarditis (LM), immunohistopathological examination of endomyocardial biopsies (EMBs) is used with a cutoff value of at least 14 leukocytes per mm², composed of CD3- and CD68-positive cells. We hypothesized that a more common leukocyte marker, CD45, instead of CD3 could increase the diagnostic sensitivity. Hearts of mice with acute viral myocarditis (n = 9) and of controls (n = 7) and the EMB sampling area of the left ventricular posterior wall (LVPW) obtained from autopsied hearts of patients diagnosed with LM (n = 18) and controls (n = 6) were stained with anti-CD68, anti-CD3, and anti-CD45. When applying the threshold of at least 14 leukocytes per mm², 33% of the mice would be diagnosed with LM with the use of CD3⁺CD68 and 89% with the use of CD45⁺CD68. In the EMB sampling area of autopsied hearts, using the cutoff value of at least 14 leukocytes per mm², CD3⁺CD68 could only confirm 17% of the diagnosis of LM, whereas CD45⁺CD68 could confirm 50% of the LM cases. Moreover, we compared inflammation in the EMB sampling area of the LVPW to the remaining myocardium of the LVPW and observed a significant increase of CD45⁺CD68 cells per mm² in patients with LM. In conclusion, the use of the common leukocyte marker CD45 increases the sensitivity of the diagnosis of LM. Furthermore, the inflammatory infiltrate in the EMB sampling area is significantly increased compared with the remaining LVPW, indicating that the sampling area constitutes the highest chance for histological diagnosis of LM.

A case report of lethal post-viral lymphocytic myocarditis with exclusive location in the right ventricle

The inflammatory involvement of vital organs may represent a dangerous and life-threatening situation: in particular, the inflammation of the myocardial tissue of the heart may lead to severe consequences since the clinical history of the disease may be completely asymptomatic, any clinical sign may be lacking, thus preventing correct diagnosis and treatment. This may occur even in the case of myocarditis and may lead to unexpected death whose cause can be assessable only by means of a thorough histopathological examination. The article reports the case of 61-year old female who developed a flu-like syndrome with very few symptoms, followed by sudden death in three weeks. The autopsy and following histopathological investigations identified the cause of death in a post-viral lymphocytic myocarditis, probably related to the previous infectious disease, and alternative causes (as arrhythmic ventricular dysplasia, vasculitis, sarcoidosis and giant cell myocarditis) were excluded. The exclusive location in the right ventricle was a peculiar finding. The case highlights the importance of the myocardium of the right ventricle, a tissue which is often less considered even in histopathological surveys. The exclusive location of myocarditis in the right ventricle is a rare event but in this case fully responsible for death.

Fulminant myocarditis

Myocarditis is most often caused by a viral infection. Less common causes include other infectious agents and autoimmune diseases. Fulminant myocarditis is an unusual complication with a rapidly progressive course resulting in severe heart failure and cardiogenic shock. Fulminant myocarditis should be treated with full supportive care, using aggressive pharmacologic therapy and mechanical circulatory support, because significant improvement in left ventricular function will often occur. Cardiac transplantation is required in a small minority of patients. Cardiac magnetic resonance imaging is becoming a frequently used modality to aid in the diagnosis of myocarditis.