Introduction Cannabis use is significantly increasing worldwide yet its cardiovascular effects and arrhythmogenic potential remain unclear. As legalization expands, it is critical to understand public health risks and clinical implications. This study evaluates the relationship between cannabis use and the risk of arrhythmias using a large, real-world dataset. Methods This retrospective cohort study utilized de-identified electronic health records from 68 U.S. healthcare organizations within the TriNetX network. A total of 210,817 adult cannabis users were identified and matched 1:1 with 210,817 ibuprofen users using propensity score matching across 17 baseline variables, including demographics, cardiovascular risk factors, and medication use. The primary outcomes were incident diagnoses of atrial fibrillation/flutter (AF/AFL), paroxysmal tachycardia, premature beats, and ventricular tachycardia/fibrillation (VT/VF). Outcomes were assessed using Cox proportional hazards models and Kaplan-Meier survival analyses. Results Cannabis use was significantly associated with an increased risk of multiple arrhythmias compared to ibuprofen use. The incidence of AF/AFL was 1,895 vs 1,332 cases (HR = 1.549, 95% CI: 1.444–1.662, p < 0.001). Paroxysmal tachycardia occurred in 1,065 vs 672 patients (HR = 1.791, 95% CI: 1.626–1.973, p < 0.001), and premature beats in 1,135 vs 745 patients (HR = 1.739, 95% CI: 1.585–1.908, p < 0.001). The most pronounced relative risk was observed for VT/VF, with 97 vs 35 cases (HR = 3.078, 95% CI: 2.089–4.533, p < 0.001). All associations remained statistically significant after adjustment, and Kaplan-Meier curves demonstrated lower arrhythmia-free survival in cannabis users across all endpoints. Conclusion Cannabis use was associated with an increased risk of multiple arrhythmias, particularly atrial fibrillation and ventricular arrhythmias. These findings highlight the need for further research on the cardiovascular effects of cannabis and reinforce the importance of patient counseling regarding its potential arrhythmogenic risks.

Introduction Catheter ablation (CA) can interfere with cardiac implantable electronic device (CIED) function. The safety of CA in the 1 st year after CIED implantation/lead revision is uncertain. Methods This single center, retrospective cohort included patients who underwent CA between 2012-2017 and had a CIED implant/lead revision within the preceding year. We assessed the frequency of device/lead malfunction in this population. Results We identified 1810 CAs in patients between 2012-2017, with 170 CAs in 163 patients within a year of a CIED implant/lead revision. Mean age 68 ± 12 years (68% men). Time between the CIED procedure and CA was 158 ± 99 days. The CA procedures included AF ablation (n=54, 32%), AV node ablation (n=41, 24%), atrial flutter ablation (n=25, 15%), and PVC/VT ablations (n=24, 14%). The cumulative frequency of lead dislodgement, significant CIED dysfunction, and/or CIED-related infection following CA was (n=1/170, 0.6%). There was a single atrial lead dislodgement (0.6%). There were no instances of power-on-reset or CIED-related infection. Following CA, there was no significant difference in RA or RV lead sensing (p=0.52 and 0.84 respectively) or thresholds (p=0.94 and 0.17 respectively). The RA impedance slightly decreased post-CA from 474 ± 80 Ohms to 460 ± 73 Ohms (p=0.002), as did the RV impedance (from 515 ± 111 Ohms to 497 ± 98 Ohms, p<.0001). Conclusions CA can be performed within 1 year following CIED implantation/lead revision with a low risk of CIED/lead malfunction or lead dislodgement. The ideal time to perform CA after a CIED remains uncertain.