Zhang SS; Department of Cardiology, Beijing, China,
Jiang LY; Zuo HJ; Liu WJ

Cardiovascular therapeutics. 2026(1):e3611934, 2026.

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.