JCS 2023 Guideline on the Diagnosis and Treatment of Myocarditis

Effects of Cardioprotective Drugs on 90-Day Mortality or Heart Transplantation in Patients With Fulminant Myocarditis

Background

Cardioprotective drugs have not been previously shown to improve the prognosis in patients with fulminant myocarditis presentation (FMP). We aimed to investigate whether cardioprotective drugs, including angiotensin-converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB) and β-blocker, administered during hospitalization improved the prognosis in patients with FMP.

Methods and Results

This multicenter cohort study conducted in Japan included 755 patients with clinically diagnosed FMP. Those who died within 14 days of admission were excluded, and 588 patients (median age 53 [37-65] years and 40% female) were evaluated. The primary outcome was the composite of 90-day mortality or heart transplantation. The patients were divided into 4 groups according to whether they were administered ACEI/ARB or β-blocker during hospitalization. Administration of ACEI/ARB without β-blocker improved the overall patient outcomes (log-rank test [vs. ACEI/ARB - and β-blocker -]: ACEI/ARB + and β-blocker -, P<0.001; ACEI/ARB - and β-blocker +, P=0.256). Subsequently, a matched cohort of 146 patient pairs was generated for patients with or without ACEI/ARB administration during hospitalization. The outcome-free survival at 90 days was significantly higher in the ACEI/ARB administration group than in the non-administration group (hazard ratio 0.37; 95% confidence interval 0.19-0.71).

Conclusions

Administration of ACEI or ARB during hospitalization was associated with favorable outcomes in terms of 90-day mortality and heart transplantation events in patients with clinically diagnosed FMP.

Cardiac magnetic resonance imaging (MRI) for detecting acute myocardial injury of fulminant myocarditis survivors after extracorporeal membrane oxygenation (ECMO) treatment in adults

AIMS

To detect the acute myocardial injury in fulminant myocarditis (FM) survivors after extracorporeal membrane oxygenation (ECMO) and to demonstrate its significant differences from non-FM patients by cardiac magnetic resonance (CMR).

MATERIALS AND METHODS

This retrospective study enrolled 59 patients with acute myocarditis (AM), including 35 non-FM patients, 24 FM patients, and 54 controls. The peak value of cardiac troponin T (cTnT) was recorded. Tissue parameters, including native T1, extracellular volume (ECV), late gadolinium-enhancement (LGE)%, and T2 by CMR were assessed.

RESULTS

The mean age was 35 ± 14 years, and 45.8% of the population were males in the AM group. Patients had higher levels of peak cTnT, peak NT-proBNP and peak C-reactive protein in the FM group (all p<0.05). Comparing with non-FM, the values of T1-based imaging parameters were significantly higher in the FM group (all p<0.05). In contrast, no difference was observed among the two groups in terms of T2 value (p=0.707). The septal area was more frequently involved in FM survivors after ECMO treatment, both in T1 and T2-based images. In addition, the cubic relationship was the relative best fit of LGE% against logcTnT and indicated that cTnT value exceeding 300ng/L exhibited a rapid upward trend of LGE%.

CONCLUSION

Comparing to non-FM, higher myocardial necrosis and fibrosis but similar edema determined by T1 and T2 based imaging was found in FM survivors after ECMO treatment. Furthermore, the inter-ventricular septal area was more frequently involved by acute myocardial injury in FM survivors after ECMO treatment. In addition, LGE% showed an overall increasing trend with cTnT values elevating with rapidly increasing with cTnT exceeding 300 ng/L.

Rare pediatric case of two episodes of fulminant myocarditis and cardiac dysfunction after viral infection

Myocarditis presents with a broad spectrum of clinical severity, ranging from subclinical illness to sudden death. Children with fulminant myocarditis often require inotropic or mechanical circulatory support; however, recurrent acute myocarditis is extremely rare. There is limited evidence to guide the management of recurrent acute myocarditis because the relevant literature is sparse. Here, we present a rare pediatric case of recurrent acute myocarditis. This patient experienced two episodes of fulminant myocarditis and two episodes of suspected myocarditis over an eight-year period; each episode fully resolved with preserved cardiac function. Three episodes were associated with influenza virus infection. During each episode, the electrocardiography, echocardiogram, and laboratory findings improved. Autoimmune and chronic myocarditis were not suspected because of the rapid onset of myocarditis associated with viral infection. Genetic testing by next-generation sequencing was performed; however, no underlying genetic illnesses were identified. Human leukocyte antigen genotyping was performed, and the results determined the genotype to be HLA-DQB1*0302/0303, which reports indicate might be involved in the development of myocarditis in mice or humans. The combination of these genotypes in myocardial cells may be associated with susceptibility to influenza infection or acute myocarditis.

Learning objective

There is little evidence regarding susceptibility to myocarditis. We present a pediatric patient who experienced two episodes of fulminant myocarditis and two episodes of suspected myocarditis associated with influenza infection and a specific human leukocyte antigen genotype. This case highlights the importance of understanding myocarditis susceptibility.

Long-term imaging analysis of a myocarditis case: Utilizing strain with echocardiography and cardiovascular magnetic resonance findings

Herein, we report a case of myocarditis in a 27-year-old male with long-term follow-up using longitudinal peak systolic strain (LPSS) measurements with transthoracic echocardiography (TTE) and late gadolinium enhancement (LGE) in cardiovascular magnetic resonance imaging (CMR). On admission, a predominant decrease was observed in the LPSS in the posterolateral segments of the TTE. After a period of two weeks, the values of the LPSS observed in the posterolateral segments were still slightly reduced, which is consistent with the LGE results in CMR. After a duration of 16 months, an improvement was noted in the LPSS and LGE results in all the segments. Moreover, a time-phase discrepancy was observed in the segmental longitudinal strain curve for a period of two weeks from the onset of myocarditis. However, an improvement in the discrepancy was detected after 16 months.

Learning objective

Longitudinal peak systolic strain (LPSS) on transthoracic echocardiography (TTE) has predominantly focused on diagnosing the acute phase of myocarditis. Herein, LPSS was evaluated not only in the acute phase but also in the chronic phase. Furthermore, the relationship between the results of segmental LPSS and late gadolinium enhancement was documented. We would like to emphasize the usefulness of LPSS on TTE both for identifying myocarditis and as a tool for the long-term follow-up of patients.

Chronic active myocarditis with spatially and temporally heterogeneous lesions causing severe heart failure and intractable atrial arrhythmia: An autopsy case report

The pathogenesis of chronic active myocarditis remains unclear. A 65-year-old man underwent permanent pacemaker implantation for sick sinus syndrome and pulmonary vein isolation for paroxysmal atrial fibrillation. Four years later, the left ventricular ejection fraction decreased from 51 % to 35 %, and the apical left ventricular inferior wall developed akinesis. Isolated cardiac sarcoidosis was suspected; however, prednisolone and optimal medical therapy failed to improve the symptoms. Even after cardiac resynchronization therapy followed by atrioventricular junction ablation for untreatable atrial tachycardia, the patient died of heart failure eight years after referral. An autopsy revealed inflammatory cell infiltration accompanied by cardiac myocytolysis in both atria and ventricles. He was diagnosed with chronic active myocarditis based on pathological findings and a persistent increase in the blood high-sensitivity cardiac troponin levels before death. The myocardium around the sinus node showed extensive and severe fibrosis with mild inflammation, suggesting a chronic inflammatory phase. In contrast, the left atrium and both ventricles showed active myocardial inflammation with fibrosis, suggesting a persistently active inflammatory phase. This case demonstrated that atrial inflammation caused intractable atrial arrhythmia, while ventricular inflammation led to biventricular heart failure, and highlighted the presence of spatially and temporally heterogeneous inflammation in chronic active myocarditis.

Learning objective

We describe a case of chronic active myocarditis with spatially and temporally heterogeneous lesions throughout the four cardiac chambers. Inflammatory cell infiltration was observed in both atria and ventricles. Extensive fibrosis replaced the myocardium around the sinus node, suggesting a chronic phase. The left atrium and ventricles showed active inflammation, suggesting an active phase. Atrial and ventricular inflammation led to atrial arrhythmia and heart failure, respectively.

Paradigm shift in myocarditis treatment

Although most cases of myocarditis are self-limiting with a gradual improvement in cardiac function, the involvement of myocarditis in sudden cardiac death among children and young adults remains substantial, with rates of 3-17 % and 8.6-12 %, respectively. Moreover, the risk of developing chronic dilated cardiomyopathy ranges from 21 % to 30 % in all cases confirmed by biopsy. Current therapeutic strategies for myocarditis and its complications range from standard supportive care for heart failure and arrhythmias to etiologically oriented, case-based therapeutic options. For example, immunosuppression is indicated only in certain forms of acute myocarditis with clinical or endomyocardial biopsy evidence of immune checkpoint inhibitor-induced myocarditis and autoimmune diseases, including giant cell myocarditis, eosinophilic myocarditis, vasculitis, or cardiac sarcoidosis. However, our views on myocarditis treatment have changed considerably over the past two decades, thanks to the emergence of regenerative cells/tissues as well as drug and gene delivery systems. Cell-based therapies are now growing in popularity in any field of medicine. Studies evaluating the therapeutic efficacy of different stem cells in the treatment of acute myocarditis and its chronic complications have shown that although the experimental characteristics varied from study to study, in general, these strategies reduced inflammation and myocardial fibrosis while preventing myocarditis-induced systolic dysfunction and adverse remodeling in animal models.

Myocardial Oedema as a Consequence of Viral Infection and Persistence-A Narrative Review with Focus on COVID-19 and Post COVID Sequelae

Microvascular integrity is a critical factor in myocardial fluid homeostasis. The subtle equilibrium between capillary filtration and lymphatic fluid removal is disturbed during pathological processes leading to inflammation, but also in hypoxia or due to alterations in vascular perfusion and coagulability. The degradation of the glycocalyx as the main component of the endothelial filtration barrier as well as pericyte disintegration results in the accumulation of interstitial and intracellular water. Moreover, lymphatic dysfunction evokes an increase in metabolic waste products, cytokines and inflammatory cells in the interstitial space contributing to myocardial oedema formation. This leads to myocardial stiffness and impaired contractility, eventually resulting in cardiomyocyte apoptosis, myocardial remodelling and fibrosis. The following article reviews pathophysiological inflammatory processes leading to myocardial oedema including myocarditis, ischaemia-reperfusion injury and viral infections with a special focus on the pathomechanisms evoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In addition, clinical implications including potential long-term effects due to viral persistence (long COVID), as well as treatment options, are discussed.

Naphazoline intoxication with transient QT prolongation and acute myocardial injury

A 27-year-old Japanese woman with a history of depression and an eating disorder presented to our emergency department with a chief complaint of generalized weakness. Electrocardiography showed prominent QT prolongation with multiple ventricular contractions. Chest X-ray plain computed tomography revealed pulmonary edema. Echocardiography showed decreased left ventricular systolic function. Suspecting acute myocarditis, we performed a myocardial biopsy from the right ventricular septum. The biopsy histology revealed extensive myocardial fibrosis and a very mild inflammatory cell infiltrate. In an additional detailed medical interview, the patient admitted that she had consumed three bottles of a first-aid liquid containing naphazoline approximately ~12 h before her presentation, in a suicide attempt. Her QTc and left ventricular ejection fraction improved during hospitalization.

Learning objective

Acute drug intoxication can cause QT prolongation and ventricular arrhythmias, cardiomyopathy, and pulmonary edema. When acute QT prolongation, myocardial damage, and pulmonary edema are seen (suggesting acute myocarditis), naphazoline intoxication should be investigated in the differential diagnosis.

Clinical Value of Troponin Levels to Cardiac Function and Prognosis in Patients with Fulminant Myocarditis

Troponin (Tn) is a biomarker related to myocardial necrosis and is elevated in patients with myocarditis. This study aimed to investigate the association between cardiac Tn levels and the course of cardiac function, and prognosis in patients with fulminant myocarditis (FM) receiving percutaneous mechanical circulatory support (MCS).We used data from a multicenter retrospective registry, CHANGE PUMP 2, which included 216 patients with FM who required MCS. Among them, 141 patients whose Tn levels were available were analyzed. The patients were divided into low and high Tn groups according to the median values of TnT and TnI.The median age was 54 years, and 59.6% were male. The TnT and TnI on day 1 (at MCS initiation) were 3.8 (1.4-10.0) and 21.4 (8.4-68.8) ng/mL. While the left ventricular ejection fraction (LVEF) was similar on day 1 (25.0% versus 24.5%), the low Tn group showed better LVEF improvement on day 7 than the high Tn group (45.0% versus 25.3%, P < 0.001). LVEF at 1 year after admission was higher in the low Tn group (65.0% versus 59.7%, P = 0.039). The low Tn group had a better 90-day composite endpoint in death, durable left ventricular assist device implantation, and heart transplantation compared to the high Tn group (hazard ratio 0.47, 95% CI 0.23-0.95).Tn levels were associated with short- and long-term cardiac recovery and adverse outcomes in patients with FM receiving MCS due to cardiogenic shock.

Successful treatment of fulminant myocarditis due to COVID-19 in a 5-year-old girl

Reports of acute myocarditis are increasing due to the worldwide spread of coronavirus disease 2019 (COVID-19). We report a case of a 5-year-old girl with fulminant myocarditis caused by COVID-19, who was successfully treated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO). The unvaccinated patient had developed fever 1 week before attending our hospital and was "presumptive positive" for COVID-19 based on the surrounding infectious situation. The fever resolved, but the day before the visit, abdominal pain appeared. The patient visited her previous physician with vomiting as the main complaint. She was transferred to our hospital due to impaired consciousness and bradycardia, with a heart rate of 40 beats/min. Immediately after transfer, she was diagnosed with complete atrioventricular (AV) block and was scheduled to undergo percutaneous pacing lead insertion. However, the patient had ventricular tachycardia, AV block and hypotension intraoperatively and required cardiopulmonary resuscitation. The patient was in an extremely unstable circulatory state, and VA-ECMO was urgently introduced. After multidisciplinary treatment for acute myocarditis, waiting for an improvement in AV block, and recovery of cardiac function, the patient was weaned from VA-ECMO on the eighth day after admission. The patient was discharged with no cardiac or neurologic sequelae.

Learning objective

The rapid introduction of veno-arterial extracorporeal membrane oxygenation for fulminant myocarditis caused by coronavirus disease 2019 (COVID-19) in young children is extremely effective. Vaccination may be important for preventing infection with COVID-19 and avoiding severe complications.

Update on Myocarditis: From Etiology and Clinical Picture to Modern Diagnostics and Methods of Treatment

Although the frequency of myocarditis in the general population is very difficult to accurately determine due to the large number of asymptomatic cases, the incidence of this disease is increasing significantly due to better defined criteria for diagnosis and the development of modern diagnostic methods. The multitude of different etiological factors, the diversity of the clinical picture, and the variability of the diagnostic findings make this disease often demanding both for the selection of the diagnostic modality and for the proper therapeutic approach. The previously known most common viral etiology of this disease is today overshadowed by new findings based on immune-mediated processes, associated with diseases that in their natural course can lead to myocardial involvement, as well as the iatrogenic cause of myocarditis, which is due to use of immune checkpoint inhibitors in the treatment of cancer patients. Suspecting that a patient with polymorphic and non-specific clinical signs and symptoms, such as changes in ECG and echocardiography readings, has myocarditis is the starting point in the diagnostic algorithm. Cardio magnetic resonance imaging is non-invasive and is the gold standard for diagnosis and clinical follow-up of these patients. Endomyocardial biopsy as an invasive method is the diagnostic choice in life-threatening cases with suspicion of fulminant myocarditis where the diagnosis has not yet established or there is no adequate response to the applied therapeutic regimen. The treatment of myocarditis is increasingly demanding and includes conservative methods of treating heart failure, immunomodulatory and immunospressive therapy, methods of mechanical circulatory support, and heart transplantation. The goal of developing new diagnostic and therapeutic methods is to reduce mortality from this complex disease, which is still high.