Impaired cardiac pump function assessment with normalized cardiac power using cardiac magnetic resonance in patients with hypertrophic cardiomyopathy

BACKGROUND: Cardiac power (CP; CP = 0.222 × cardiac output × mean blood pressure) output in patients with heart failure has been studied previously, but its importance in patients with hypertrophic cardiomyopathy (HCM) remains unclear. The present study aimed to explore the role of normalized CP (normalized CP = CP/ventricle mass) in assessing cardiac function in patients with HCM with normal ejection fraction using cardiac magnetic resonance (CMR). METHODS: This cross-sectional study enrolled 99 patients with HCM who underwent CMR from December 2020 to January 2022 at Beijing Anzhen Hospital, and these patients were classified into heart failure or non-heart failure subgroups. Meanwhile, a control group comprising 65 gender- and age-matched healthy volunteers was also enrolled. The baseline clinical characteristics and cardiac functional parameters were compared between the patients with HCM and the controls, and multivariable linear regression analysis was performed to analyze the relationship between normalized CP and the relevant factors. RESULTS: Significantly higher CP (1.19 vs. 1.01 W; P=0.03) but lower normalized CP (0.73 vs. 1.12 W/100 g; P<0.001) were found in patients with HCM as compared with the controls. Multivariable analysis showed that HCM correlated well with normalized CP [β=−0.235; 95% confidence interval (CI): −0.341 to −0.129; P<0.001]. In the HCM group, there were 34 cases with heart failure and 65 with non-heart failure, and the patients with HCM with heart failure showed similar CP (1.14 vs. 1.24 W; P=0.06) but significantly lower normalized CP (0.54 vs. 0.78 W/100 g; P<0.001). The correlation analysis of normalized CP and functional parameters revealed that normalized CP was inversely correlated with left ventricle mass/body surface area (R=−0.509; 95% CI: −0.646 to −0.341; P<0.001) in patients with HCM. CONCLUSIONS: Normalized CP decreased significantly and was negatively correlated with ventricle mass, indicating impaired cardiac pump function in patients with HCM. Normalized CP might play a critical role in detecting and evaluating impaired cardiac pump function in patients with HCM with preserved ejection fraction.