Clinical Characteristics and Prognostic Factors of Myocarditis in New Zealand Patients

Clinical Characteristics and Mechanisms of Acute Myocarditis

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05335928.

Diagnostic accuracy, clinical characteristics, and prognostic differences of patients with acute myocarditis according to inclusion criteria

INTRODUCTION

The diagnosis of acute myocarditis (AM) is complex due to its heterogeneity and typically is defined by either Electronic Healthcare Records (EHRs) or advanced imaging and endomyocardial biopsy, but there is no consensus. We aimed to investigate the diagnostic accuracy of these approaches for AM.

METHODS

Data on ICD 10th Revision(ICD-10) codes corresponding to AM were collected from two hospitals and compared to cardiac magnetic resonance (CMR)-confirmed or clinically suspected (CS)-AM cases with respect to diagnostic accuracy, clinical characteristics, and all-cause mortality. Next, we performed a review of published AM studies according to inclusion criteria.

RESULTS

We identified 291 unique admissions with ICD-10 codes corresponding to AM in the first three diagnostic positions. The positive predictive value of ICD-10 codes for CMR-confirmed or CS-AM was 36%, and patients with CMR-confirmed or CS-AM had a lower all-cause mortality than those with a refuted diagnosis (P = 0.019). Using an unstructured approach, patients with CMR-confirmed and CS-AM had similar demographics, comorbidity profiles and survival over a median follow-up of 52 months (P = 0.72). Our review of the literature confirmed our findings. Outcomes for patients included in studies using CMR-confirmed criteria were favourable compared to studies with endomyocardial biopsy-confirmed AM cases.

CONCLUSION

ICD-10 codes have poor accuracy in identification of AM cases and should be used with caution in clinical research. There are important differences in management and outcomes of patients according to the selection criteria used to diagnose AM. Potential selection biases must be considered when interpreting AM cohorts and requires standardization of inclusion criteria for AM studies.

Sex differences in left-ventricular strain in a murine model of coxsackievirus B3 myocarditis

Myocarditis is typically caused by viral infections, but most cases are thought to be subclinical. Echocardiography is often used for initial assessment of myocarditis patients but is poor at detecting subtle changes in cardiac dysfunction. Cardiac strain, such as global longitudinal strain (GLS) and global circumferential strain (GCS), represents an increasingly used set of measurements which can detect these subtle changes. Using a murine model of coxsackievirus B3 myocarditis, we characterized functional changes in the heart using echocardiography during myocarditis and by sex. We found that 2D GLS, 4D mode, and 4D strains detected a significant reduction in ejection fraction and GLS during myocarditis compared to baseline and in males compared to females. Furthermore, worse GLS correlated to increased levels of CD45+, CD11b+, and CD3+ immune cells. Our findings closely resemble published reports of GLS in patients with myocarditis indicating the usefulness of this animal model for translational studies of myocarditis.

Sex and gender differences in myocarditis and dilated cardiomyopathy: An update

In the past decade there has been a growing interest in understanding sex and gender differences in myocarditis and dilated cardiomyopathy (DCM), and the purpose of this review is to provide an update on this topic including epidemiology, pathogenesis and clinical presentation, diagnosis and management. Recently, many clinical studies have been conducted examining sex differences in myocarditis. Studies consistently report that myocarditis occurs more often in men than women with a sex ratio ranging from 1:2-4 female to male. Studies reveal that DCM also has a sex ratio of around 1:3 women to men and this is also true for familial/genetic forms of DCM. Animal models have demonstrated that DCM develops after myocarditis in susceptible mouse strains and evidence exists for this progress clinically as well. A consistent finding is that myocarditis occurs primarily in men under 50 years of age, but in women after age 50 or post-menopause. In contrast, DCM typically occurs after age 50, although the age that post-myocarditis DCM occurs has not been investigated. In a small study, more men with myocarditis presented with symptoms of chest pain while women presented with dyspnea. Men with myocarditis have been found to have higher levels of heart failure biomarkers soluble ST2, creatine kinase, myoglobin and T helper 17-associated cytokines while women develop a better regulatory immune response. Studies of the pathogenesis of disease have found that Toll-like receptor (TLR)2 and TLR4 signaling pathways play a central role in increasing inflammation during myocarditis and in promoting remodeling and fibrosis that leads to DCM, and all of these pathways are elevated in males. Management of myocarditis follows heart failure guidelines and there are currently no disease-specific therapies. Research on standard heart failure medications reveal important sex differences. Overall, many advances in our understanding of the effect of biologic sex on myocarditis and DCM have occurred over the past decade, but many gaps in our understanding remain. A better understanding of sex and gender effects are needed to develop disease-targeted and individualized medicine approaches in the future.

Acute myocarditis revealing autoimmune and inflammatory disorders: Clinical presentation and outcome

BACKGROUND

Acute myocarditis (AM) may be the heralding manifestation of autoimmune and inflammatory disorders (AIID). We aimed to describe the clinical presentation and outcome of patients with AM revealing AIID.

METHODS

All consecutive adult patients with AM admitted in a department of Cardiology (Bichat Hospital, Paris, France) from January 2011 to January 2019 were included. Diagnosis of AM was based on clinical manifestations, elevated Troponin, myocardial inflammation on CMR and no evidence for coronary artery disease. AIID were classified using international criteria.

RESULTS

Two-hundred and eighteen (35.3 [26.4-47.1] years, 75.2% males) patients with AM were included. Overall, AM revealed AIID in 15 (6.9%), including systemic lupus erythematosus (n = 3), adult onset Still's disease (n = 3), sarcoidosis (n = 2), mixed connective tissue disease (n = 1), anti-Jo1 syndrome (n = 1), eosinophilic granulomatosis with polyangiitis (n = 1), antiphospholipid syndrome (n = 1), reactive arthritis (n = 1), Graves' disease (n = 1) and Crohn's colitis (n = 1). Left ventricular ejection fraction (LVEF) at onset was <30% in 5 (33.3%) patients with AIID. All but 2 patients with AIID were treated with steroids, immunosuppressive and/or immunomodulatory drugs and LVEF normalized in all by the end of follow-up. By comparing patients with AIID to patients with idiopathic AM (n = 203), multivariable analysis showed that pericardial effusion, lack of chest pain and high CRP level at onset were independently associated with AIID.

CONCLUSION

Acute myocarditis revealing AIID may be life-threatening at the acute phase but has an overall good prognosis under specific treatment. Pericardial effusion and CRP level at admission suggest an AIID as the cause for AM.