Biomarkers and Personalized Medicine in Cardiovascular Disease Symposium

Cardiac Testing and Return-to-Exercise Guidance in Non-Fulminant Myocarditis: A Mixed-Methods Study

Oscar P. Levine, MD¹; Mark Wendle, MD¹; David Torres Barba, MD, PhD²; Ori Ben-Yehuda, MD²

Affiliations:

¹ Division of General Internal Medicine, Department of Medicine, University of California San Diego

402 Dickinson St, Ste 380

San Diego, CA 92103, USA

² Division of Cardiovascular Medicine, Department of Medicine, University of California San Diego

9434 Medical Center Drive

San Diego, CA 92037, USA

Background: Cardiac testing, including cardiac troponin levels, transthoracic echocardiography (TTE), and cardiac magnetic resonance (CMR), is central to risk stratification and guides return-to-exercise recommendations following myocarditis. However, contemporary guidelines show limited uniformity regarding the optimal selection and use of cardiac testing modalities to guide patients through the recovery phase. Furthermore, real-world practice patterns and patient experiences remain poorly characterized.

Methods: We conducted a single-center mixed-methods study of adults aged ≤50 years hospitalized with non-fulminant myocarditis between July 1, 2014 and June 30, 2024. Quantitative data including cardiac troponin, TTE, CMR, ambulatory rhythm monitoring, and exercise stress testing were abstracted from the electronic medical record. Exercise recommendations were obtained from patient discharge instructions and stratified by ejection fraction (EF) at presentation. Semi-structured interviews were conducted with a subset of patients to explore experiences with myocarditis follow-up and were analyzed using reflexive thematic analysis.

Results: The cohort included 57 patients (mean age 27.6 ± 7.7 years). Documented discharge instructions showed no evidence of a trend toward longer restriction among patients with EF <50% versus EF ≥50% at presentation when analyzed ordinally (no restriction, <3 months, ≥3 months; p = 0.43). Among 37 (64.9%) patients with documented outpatient follow-up, repeat troponin testing was performed in 22 (59.5%) patients, of whom 18 (81.8%) demonstrated normalized levels. Follow-up TTE was obtained in 26 (70.3%) patients; all 8 patients with EF <50% at presentation who underwent follow-up TTE demonstrated recovery of EF to ≥50% at follow-up. Use of other assessments was infrequent, including CMR (18.9%), ambulatory rhythm monitoring (16.2%), and exercise stress testing (10.8%). Qualitative interviews (n=16) identified two major themes related to return-to-exercise guidance and cardiac testing: (1) inconsistent and nonspecific exercise guidance; and (2) additional testing as a source of reassurance during recovery.

Conclusions: In this mixed-methods study of patients hospitalized with non-fulminant myocarditis, discharge exercise recommendations were not consistently aligned with disease severity, and patients often interpreted them as non-specific. Additionally, basic follow-up cardiac testing consisting of repeat cardiac troponin and TTE was performed in the majority of patients with documented follow-up and showed favorable recovery trajectories. However, more advanced evaluations, including CMR, ambulatory rhythm monitoring, and stress testing, were infrequently implemented despite being valued by patients as a source of reassurance and selectively recommended by contemporary guidelines.

Keywords: Myocarditis, troponin, transthoracic echocardiography, cardiac magnetic resonance, risk stratification, return-to-exercise, mixed-methods

Disclosures: The authors report there are no competing interests to declare.