Case summary
A 26 years old young medical intern with history of chronic marijuana
usage presented with complains of dizziness and recurrent syncope. Heart
rate at presentation was 42 beats per minute and rest of the physical
examination was unremarkable. There was high grade atrioventricular
block in the Electrocardiogram (ECG) and subsequent electrophysiological
(EP) study showed high grade supra-hisian (nodal)atrioventricular block
with mildly prolonged his-ventricular (HV) interval. Urinary screen was
positive for Δ9-tetrahydrocannabinol (THC). After ruling out other
possible causes, diagnosis of high-grade AV block due chronic marijuana
use was made. Dual chamber pacemaker was implanted, and patient was
discharged in stable condition. The heart rhythm completely improved at
three-month follow-up.