Effect of Cardiac Myosin Inhibitors on Echocardiographic Features of Cardiac Structure and Function in Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis

Background: Recent advancements have introduced novel cardiac myosin inhibitors (CMIs) that have demonstrated significant efficacy in treating hypertrophic cardiomyopathy (HCM). This meta-analysis aimed to clarify the current understanding of the impact of CMIs on echocardiographic cardiac structure and function in patients with HCM. Methods: A comprehensive search of the PubMed, Cochrane Library, and Embase databases was conducted from inception until September 14, 2025. The studies reporting the impact of CMIs on echocardiographic cardiac structure and function in HCM patients were included. Results: Ultimately, this meta-analysis included 10 studies: five randomized controlled trials (RCTs), three echocardiographic sub-studies derived from RCTs, and two long-term cohort studies. A total of 938 patients were enrolled in these studies. This meta-analysis revealed that CMIs significantly reduce interventricular septum thickness (mean difference (MD): –1.77, 95% confidence interval (CI): –3.30 to –0.23; p = 0.0240). CMIs were also shown to significantly reduce left ventricular mass index (MD: –18.15, 95% CI: –32.65 to –3.65; p = 0.0141). Moreover, the pooled results demonstrated that administering CMIs can significantly reduce left ventricular ejection fraction (MD: –3.22, 95% CI: –5.60 to –0.85; p = 0.0078). CMIs also significantly improved echocardiographic parameters of left ventricular diastolic function, such as the left atrial volume index (MD: –5.75, 95% CI: –7.87 to –3.64; p < 0.0001) and septal E/e′ ratio (MD: –3.80, 95% CI: –4.74 to –2.87; p < 0.0001). However, the results did not reveal an association between CMIs and the risk of atrial arrhythmias (risk ratio (RR): 0.98, 95% CI: 0.33 to 2.94; p = 0.9689). Conclusions: CMIs have shown great efficacy in improving left ventricular structure and diastolic function in HCM patients. Additionally, CMIs can reduce left ventricular ejection fraction. However, the impact of CMIs on the risk of atrial arrhythmias remains unclear. The PROSPERO Registration: CRD420251243904, https://www.crd.york.ac.uk/PROSPERO/view/CRD420251243904.