Abstract Body (Do not enter title and authors here): Introduction: Cannabis has been increasingly used as a recreational drug. Its cardiovascular effects depend on several factors, including the exact composition, route of administration, dose, and duration of use. Here we report a case of cannabis induced junctional bradycardia in a patient with cardiovascular comorbidities.

Case description: A 68-year-old male with history of chronic systolic heart failure, coronary artery disease, diabetes, hypertension and chronic kidney disease was referred to the hospital from outpatient clinic for bradycardia with heart rate 25-35. Patient did not report any symptoms and was hemodynamically stable. He was euvolemic on physical exam. Electrocardiogram (ECG) and telemetry revealed junctional bradycardia with heart rate in 30s and sinus pauses (5-7 seconds). Initial laboratory analysis was unremarkable. He was admitted for further workup of bradycardia. His home medications included metoprolol succinate 25mg daily which was held given bradycardia. Urine drug screen was positive for cannabis. Patient endorsed that he had recently started smoking marijuana to help him with sleep and anxiety. Echocardiogram was unchanged from baseline. He was monitored on telemetry and the heart rate improved to 60-70s in about 24-48 hours without any other intervention. The temporal relationship between cannabis initiation and spontaneous resolution of bradycardia favored a potential causal link for cannabis- induced mechanism for the junctional bradycardia. Patient was resumed on metoprolol prior to discharge and tolerated it well without any bradycardic episodes establishing further that this was not iatrogenic bradycardia. He was counseled to abstain from cannabis use.

Conclusion: At low to moderate doses, cannabis can lead to a surge in sympathetic activity causing tachycardia and hypertension, while parasympathetic activity is predominant at higher doses, causing bradycardia and hypotension. Understanding these nuanced effects is crucial for clinicians when evaluating patients especially those with pre-existing cardiovascular conditions. Guidelines should be refined for safer use as the landscape of cannabis legislation evolves.