Gómez, Eduardo Martínez

ABSTRACT Introduction Cardiac myosin inhibitors (CMIs) improve hemodynamics and symptoms in hypertrophic cardiomyopathy (HCM), but recent real‐world data have raised concerns regarding an increased risk of atrial fibrillation (AF). We sought to reassess AF risk using randomized controlled trial (RCT) evidence and to contextualize discrepancies with observational reports. Methods and Results We performed a systematic review and random‐effects meta‐analysis of RCTs evaluating the effect of CMIs on incident AF in HCM. MEDLINE, Scopus, and CENTRAL were searched through November 25, 2025. Eight RCTs ( n = 1581) comparing mavacamten or aficamten with placebo or active control were included. Event counts were pooled as risk ratios (RRs) with 95% confidence intervals (CIs). CMIs were not associated with increased AF risk (RR 1.11, 95% CI 0.62–1.98; heterogeneity I 2 = 0%). No differences were observed between mavacamten and aficamten, with consistent findings across HCM subtypes (obstructive and non‐obstructive). Importantly, most trials (7/8) excluded patients with uncontrolled, persistent, or permanent AF, five excluded paroxysmal AF at screening, and one excluded any AF history. Baseline left atrial enlargement was generally in the mild to moderate range across trials, suggesting limited representation of high‐risk AF phenotypes. Conclusion Randomized evidence to date does not demonstrate an increased AF risk with CMIs. Differences between RCT populations and real‐world cohorts, including restrictive AF eligibility criteria, lower baseline atrial remodeling, and limited rhythm surveillance may explain discordant observational findings and highlight the need for longitudinal monitoring in clinical practice.

Abstract Background Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) uses angiotensin-converting enzyme 2 (ACE2) receptor as a means to enter the host. High density of ACE2 receptor in vascular endothelial cells may explain why vascular complications related to endothelial dysfunction occur in COVID-19. However, in vivo assessment of vascular endothelial function during COVID-19 has not been reported. Objective To investigate the vascular endothelial function and its temporal changes in COVID-19 patients. Methods In this prospective blinded study, systemic endothelial function was assessed using plethysmography-derived peripheral arterial tonometry (PAT). The reactive hyperemia index (LnRHI), a measure of endothelium-mediated hyperaemia, and the augmentation index, a measure of arterial vascular stiffness, were measured in 102 individuals across three study groups using PAT: group 1 (active infection), constituted by 20 patients hospitalised due to acute COVID-19; group 2 (past infection), constituted by 52 patients who had recovered from COVID-19; and group 3 (controls), constituted by 30 healthcare workers not infected by SARS-CoV-2. Additionally, among group 1, PAT assessment was repeated in 14 patients several weeks after recovery from acute COVID-19. PAT studies were analysed at a blinded fashion with respect to the assigned study group. Results Lower resting PAT amplitude was found in acute COVID-19 patients compared to the other groups (ratio of arterial tone signal between hyperemia to resting condition was 1.5 [interquartile range, 1.1] in group 1, 1.3 [0.3] in group 2 and 1.2 [0.3] in group 3, p=0.041). On the contrary, no significant differences between groups were found with respect to the hyperemic PAT amplitude (867.9 [486.1] in group 1, 944.7 [748.1] in group 2 and 819.3 [639.6] in group 3, p=0.444). Due to the lower resting PAT amplitude, there was a paradoxically significantly increased LnRHI during acute COVID-19 compared to past infection and controls (0.73 [0.32] vs. 0.53 [0.31] vs. 0.44 [0.23], respectively; p=0.013) (Figure A). Furthermore, among group 1 patients, LnRHI normalised markedly from acute COVID-19 to past infection stage (0.73 [0.32] vs. 0.49 [0.28], respectively; p=0.005) (Figure B). Augmentation index was significantly higher during acute COVID-19 compared to past COVID-19 and controls (9.6 [19.1] in group 1, 6.97 [18.6] in group 2 and −0.35 [20.53] in group 3; p=0.045 for COVID groups vs. controls). Conclusions Non-invasive assessment of systemic vascular endothelial function with PAT revealed significant differences between subjects with acute COVID-19, past COVID-19 and controls. Lower baseline PAT amplitude and high augmentation index suggest vasoconstriction at rest during the acute phase of COVID-19. These findings open new research opportunities to investigate the prognostic value of PAT in COVID-19 patients. Funding Acknowledgement Type of funding sources: None.