Background: Cardiopulmonary exercise testing (CPET) is essential for assessing patients with hypertrophic cardiomyopathy (HCM), but the role of pulmonary function testing (PFT) in refining patient stratification remains underexplored. This study investigates the relationship between PFT and CPET parameters in patients with HCM. Methods: In this prospective two-centre study, 102 clinically stable patients with HCM underwent PFT and CPET. Spearman's correlation and multiple linear regression were used to assess relationships between PFT (forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1)) and CPET variables, adjusting for confounders. Results: Patients exhibited preserved lung function (mean FVC: 90.7%; FEV1: 92.5%). Strong correlations were observed between PFT and CPET metrics, including peak VO2 (FVC: r=0.649, p<0.001; FEV1: r=0.691, p<0.001) and peak ventilation (FVC: r=0.682, p<0.001; FEV1: r=0.688, p<0.001). Regression analysis confirmed independent associations between PFT and CPET performance (all p<0.001). Conclusion: PFT metrics strongly correlate with CPET parameters in HCM, suggesting that PFT could complement CPET for a more comprehensive assessment of exercise capacity and patient stratification.
