Carbon monoxide exposure and the risk of cardiac arrhythmia: a systematic review and meta-analysis

Although carbon monoxide (CO) exposure is associated with cardiovascular diseases, its relationship with cardiac arrhythmias remains unclear. This meta-analysis evaluated the association between CO exposure and arrhythmia risk in the general population and patients with implantable cardioverter-defibrillators (ICDs). PubMed, Cochrane Library, Web of Science, and Embase were searched from inception to June 2025. English-language studies investigating CO exposure and arrhythmias or ventricular arrhythmias were included. Adjusted estimates were pooled as odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CIs) using random-effects models. Heterogeneity was assessed using the I2 statistic, and study quality was evaluated using the Newcastle–Ottawa Scale. Seventeen studies were included: seven involving the general population and ten involving ICD patients. In the general population, CO exposure was significantly associated with increased arrhythmia risk (OR: 1.07; 95% CI: 1.02–1.13; p = 0.01; HR: 1.25; 95% CI: 1.01–1.53; p = 0.04). However, no significant association was observed in ICD patients for arrhythmias (OR: 1.02; 95% CI: 0.99–1.02; p = 0.20) or ventricular arrhythmias (OR: 1.03; 95% CI: 0.99–1.06; p = 0.18). These findings suggest that CO exposure increases arrhythmia risk in the general population, whereas no significant association was identified in ICD patients.