Cardiopulmonary Fitness and Exercise-Based Cardiac Rehabilitation in Patients With Myocarditis.

BACKGROUND

Cardiorespiratory fitness (CRF) is a powerful predictor of cardiovascular morbidity and mortality. The cardiopulmonary exercise test (CPET) is considered a gold standard in assessing CRF. Patients with myocarditis are recommended to abstain from exercise because of the risk of sudden cardiac death (SCD). Therefore, the clinical benefit of exercise-based cardiac rehabilitation (CR) has not been previously established in this population.

OBJECTIVE

The aim of this study is to assess the CRF of myocarditis and the safety and effectiveness of an exercise-based CR program in these populations.

METHOD: A total of 70 consecutive patients with a diagnosis of myocarditis admitted to Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology between October 2021 and December 2024 were enrolled in the current study. CPET was performed within 3-6 months of hospital discharge. The exercise-based CR program was performed for 3 months. The protocol included biomarker analysis, CPET, and standard-of-care echocardiography (including resting left ventricular ejection fraction and global longitudinal strain [GLS]). Data were collected at admission and 3 months after discharge.

RESULTS

A total of 70 patients with myocarditis were enrolled. Among them, 47 patients completed the rehabilitation program and had complete follow-up assessments, including cardiopulmonary exercise testing, and were included in the final analysis. In comparison with NFM, patients with FM were more often female, and had higher levels of creatine kinase (CK), lactate dehydrogenase (LDH), urea nitrogen (UN), N-terminus probrain natriuretic peptide (NT-proBNP), fasting blood glucose (FBG), and white blood cell (WBC). For FM, echocardiography revealed more frequently signs of left ventricular (LV) dysfunction in the form of a reduced ejection fraction (p < 0.01), and lower GLS (p < 0.01) in contrast to NFM. CPET results showed that FM patients had markedly lower exercise capacity, impaired ventilatory efficiency, and pulmonary function (p < 0.05). After the 3-month exercise-based CR program, both groups demonstrated significant improvements in peak VO2, peak workload, and MVV. However, no significant between-group differences were observed in the magnitude of improvement in CRF.

CONCLUSION

CRF was substantially impaired in patients recovering from myocarditis, particularly among those with fulminant presentations. Participation in a structured 3-month exercise-based CR program was feasible and was associated with favorable changes in exercise capacity and cardiopulmonary performance.

TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR2400088436.