Background Atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) is associated with high thromboembolic risk, morbidity, and mortality. Purpose We aimed to study the role of cardiac implantable devices (CID) for AF diagnosis in patients with HCM without prior AF history. Methods A comprehensive systematic review and meta-analysis was conducted using Pubmed, Embase, and ClinicalTrials.gov through November 2021 for studies reporting incidence of new-onset AF detected by CID including implantable cardioverter defibrillators, pacemakers, cardiac resynchronization therapy, and loop recorder devices in HCM patients. We used a Freeman-Tukey transformation to calculate the weighted summary proportion of the incidence of AF and stroke and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using a random-effects model. Results Eight cohort studies were included, totalizing 910 patients with HCM and CID without baseline AF. Mean age was 54 years and 21% were female. Mean left ventricular wall thickness was 22.6 mm. Mean follow-up was 3.1 years. New-onset AF was detected in 27.6% (95% CI 18.7–37.5) of patients (Figure A) and 84% of the episodes were subclinical. Stroke occurred in 4.7% (95% CI 1.8–9.0) of patients without baseline AF (Figure B). There was no significant difference in the unadjusted risk of stroke between patients with newly diagnosed AF vs no AF detected at the end of follow-up (9.4% vs 4.7%, OR 1.93, 95% CI 0.83–4.48, p=0.13). Conclusion There is a high incidence of subclinical new-onset AF in patients with HCM, supporting the use of CID for early detection of AF in this population. Funding Acknowledgement Type of funding sources: None.

Background Omecamtiv mecarbil (OM) is a selective cardiac myosin activator that promotes contractility in patients with Heart Failure with Reduced Ejection Fraction (HFrEF). We aimed to study the clinical outcomes of OM in this population. Methods PubMed, Cochrane CENTRAL Registry of Controlled Trials, and ClinicalTrials.gov were searched for randomized controlled trials (RCTs) that compared OM with placebo for the management of HFrEF. Efficacy and safety data were summarized with odds ratios (OR) and a 95% confidence interval (CI) using a fixed-effect model predicting low heterogeneity between studies. Results Four RCTs were included, totalizing 9,364 patients, 4,779 treated with OM and 4,585 with placebo. Mean age ranged from 63–66 years, 15–22% female, ejection fraction 26–29%, ischemic etiology 53–66%. Length of follow up ranged from 1 to 21 months. There was no difference in the outcomes all cause death (OR 0.99, 95% CI 0.9–1.1, p=0.91), cardiovascular death (OR 1.01, 95% CI 0.91–1.12, p=0.87) and heart failure events or hospitalizations (OR 0.96, 95% CI 0.87–1.05, p=0.35), Figure. Conclusion In a meta-analysis of 4 RCTs, OM showed no difference compared with placebo in the risk of all-cause death, cardiovascular death, or heart failure events among patients with HFrEF. Funding Acknowledgement Type of funding sources: None.