Israel Medical Association Journal

Background: Acute myocarditis (AM) is an inflammatory cardiac condition with heterogeneous clinical manifestations that often overlap with other acute cardiac syndromes, making diagnosis challenging.

Objectives: To characterize the prevalence, clinical profile, and outcomes of AM patients with respiratory viral pathogen detection on nasopharyngeal swabs at admission.

Methods: We retrospectively analyzed all patients admitted to the Sheba Medical Center with confirmed AM between January 2005 and December 2020. Diagnosis was based on compatible presentation, elevated cardiac biomarkers, and supportive imaging findings. Nasopharyngeal swab results, when performed, were reviewed for respiratory viral detection.

Results: Among 425 identified AM cases, 146 (34%) underwent swab testing; 11 (8%) tested positive for respiratory viral pathogens, most commonly influenza A (n=5) and adenovirus (n=3). With one exception, all positive cases occurred during winter or early spring (10/77, 13%). Compared with swab-negative patients, swab-positive individuals were older (47 ± 22 vs. 35 ± 14 years, P = 0.03), more frequently female (45% vs. 14%, P = 0.007), and more often presented with dyspnea (55% vs. 25%, P = 0.036) but less commonly with ST-segment elevation (27% vs. 70%, P = 0.003). No differences were observed in inflammatory markers, imaging findings, or hospital stay.

Conclusions: Respiratory viral detection in AM is uncommon and predominantly seasonal. Nasopharyngeal swabbing is a simple, non-invasive tool that may help identify treatable viral pathogens and guide patient management. These data provide a pre-COVID-19 reference for future studies investigating the impact of viral infection on myocardial injury.

Recognizing myocarditis is a diagnostic and therapeutic challenge due to the heterogeneity of its clinical presentation and the wide range of etiologies. There is a lack of uniformity among position papers and guidelines from various professional societies regarding the definition and diagnostic workout, including recommendations for performing endomyocardial biopsy (EMB) and medical management, especially the use of immunosuppressive regimens [1-3]. Moreover, there is significant variability among medical centers in Israel in the diagnostic and therapeutic approaches to acute myocarditis. The purpose of this position paper is to present ways to standardize the management of acute myocarditis in Israel [4] by providing up-to-date definitions of the clinical categories of myocarditis, diagnostic criteria, and therapeutic approaches that correspond to the realities of our healthcare system.

In the position statement on the definition and diagnosis of acute myocarditis on page XXX of this issue of the Israel Medical Association Journal (IMAJ), we discussed contemporary criteria for definition of acute myocarditis and inflammatory cardiomyopathy [1-6]. We also addressed current diagnostic methods including indications for endomyocardial biopsy (EMB) [7-21]. In this position statement, we discuss the management approaches during hospitalization and following hospital discharge, including specific forms of myocarditis and recommendations for returning to physical activity after myocarditis [21-36].