Myocardial Work Combined with a Cardiopulmonary Exercise Test is a Useful Prognostic Assessment of Patients with Non-obstructive Hypertrophic

Abstract

Background: The aim of this study was to evaluate the prognosis of patients with non-obstructive hypertrophic cardiomyopathy (HCM) using myocardial work combined with a cardiopulmonary exercise test (CPET). The association between myocardial work and CPET parameters and left ventricular wall thickness was investigated. To achieve the study aim, 55 patients with non-obstructive HCM and 55 healthy control participants were enrolled. Echocardiographic data were collected and compared, and a CPET was performed separately for patients with HCM and controls. Differences in CPET and myocardial work parameters and changes in myocardial work parameters from before to after the CPET were compared between the two groups. Results: Global longitudinal strain, global work index, global constructive work (GCW), and global work efficiency parameters were significantly reduced and longitudinal strain peak time dispersion (PSD) was prolonged in patients with HCM compared to controls (P < 0.001). No difference in global wasted work was observed between the two groups (P > 0.05). Regarding CPET parameters, peak oxygen uptake, anaerobic threshold, oxygen pulse, and metabolic equivalents were significantly lower in the HCM group compared with the control group (P < 0.05). The slope of carbon dioxide ventilation equivalent was higher in patients with HCM, but the between-group difference was not significant (P > 0.05). After the CPET, there was a significant increase in PSD, but not GCW, in the HCM group, while there was a significant increase in GCW, but not PSD, in the control group. Maximal wall thickness showed a significant positive correlation with PSD (r =0.84, P <0.001), a significant negative correlation with GCW (r =-0.84, P <0.001), and a weak negative correlation with peak oxygen uptake (r =-0.45, P <0.001). Conclusion: Myocardial work combined with a CPET can provide a valid assessment of the prognosis of patients with HCM. The effective myocardial work and CPET parameters are negatively correlated with left ventricular wall thickness.