Efficacy of cardiac myosin inhibitors for obstructive hypertrophic cardiomyopathy: a systematic review and meta-analysis of randomised controlled trials

Abstract

Abstract Background Obstructive hypertrophic cardiomyopathy (oHCM) is a hereditary heart disease associated with left ventricular hypertrophy and left ventricular outflow tract (LVOT) obstruction. Cardiac myosin inhibitors (CMI) have emerged as the first disease-specific, non-invasive therapy with promising results in patients with hypertrophic cardiomyopathy. However, its efficacy in the setting of oHCM remains unclear. Purpose We aimed to perform a meta-analysis of randomised controlled trials (RCTs) comparing CMI with placebo as a treatment for oHCM in terms of NYHA class improvement, provoked LVOT gradient, and quality of life. Methods We systematically searched PubMed, EMBASE, and the Cochrane Library in February 2023 using PRISMA guidelines for RCTs comparing CMI with placebo in oHCM patients. Statistical analyses were performed using R Software version 4.1.0. Between-study heterogeneity was assessed using I2 statistics. Results Three RCTs comprising 390 patients were included, of whom 193 (49.48%) were randomised to CMI. CMI were found to be significantly more effective compared with placebo in improving NYHA class (RR 2.23; 95% CI 1.75–2.85; p < 0.001; I2=0%; Fig 1A) and quality of life (SMD 0.64; 95% CI 0.43 to 0.86; p < 0.001; I2=0%; Fig 1B), as well as in reducing provoked LVOT gradients (MD -37.23 mmHg; 95% CI -41.73 to -32.73; p < 0.001; I2=18% Fig 1C). Conclusion To our knowledge, this is the first meta-analysis studying CMI versus placebo for the management of oHCM, pointing that CMI were superior to placebo with regards to improvements in NYHA class, quality of life, and LVOT gradients.Figure 1