Effect of cardiac myosin inhibitors on cardiac structure and myocardial fibrosis in obstructive hypertrophic cardiomyopathy: a meta-analysis of cardiac magnetic resonance outcomes.

AIM: Recent advancements have introduced cardiac myosin inhibitors (CMIs) that have demonstrated significant efficacy in obstructive hypertrophic cardiomyopathy (oHCM). This meta-analysis aims to synthesize the current understanding of the impact of CMIs on cardiac magnetic resonance (CMR) findings in patients with oHCM. MATERIAL AND METHODS: A search of the PubMed, Cochrane Library, and Embase databases was conducted from their inception until July 27, 2025. Random-effects models were used to pool mean differences with 95% confidence intervals. Both mavacamten and aficamten were included in all outcomes. RESULTS: Three randomised controlled trails (RCTs) involving 150 patients were included in this meta-analysis. This meta-analysis demonstrates a reduction in left ventricular mass index with CMIs compared to the placebo group (mean differences [MD]: -20.01 g/m2, 95% confidence interval [CI]: -29.77 to -10.26, P<0.0001, I2 = 67.7%). And CMIs can also reduce maximal left ventricular wall thickness (MD: -2.66 mm, 95% CI: -3.53 to -1.79, P<0.0001, I2 = 40.6%). Meanwhile, the pooled results demonstrate that CMIs reduce left atrial volume index (MD: -13.02, mL/m2 95% CI: -17.17 to -8.87, P<0.0001, I2 = 15.6%). However, the results do not show that CMIs improve late gadolinium enhancement (MD: 0.54 %, 95% CI: -0.48 to 1.56, P=0.2973, I2 = 0%). Similarly, there is no significant reduction in extracellular volume fraction (MD: 1.43 %, 95% CI: -0.02 to 2.88, P=0.0528, I2 = 0%). CONCLUSION: CMIs have shown efficacy in improving cardiac structure in oHCM. However, the impact on myocardial fibrosis remains unclear.