ECG Findings in Pediatric Patients under the Influence of Marijuana

Background: The effects of marijuana on the cardiac conduction system are ill defined. The purpose of this study is to describe the association between electrocardiogram (ECG) findings and positive urine drug screening (+UDS) for marijuana in the pediatric population. Methods: A retrospective review was conducted through the electronic medical record from Emergency Department (ED) visits dated 10/13- 11/14 of patients ≤ 18 years of age who tested positive for marijuana exposure by +UDS in the ED. Inclusion criteria included: 1) +UDS for marijuana performed in the ED and 2) electrocardiogram (ECG) performed on same day as +UDS. Each ECG was overread by a pediatric electrophysiologist, blinded to the results of the UDS. Results: There were 174 patients identified in the ED with a +UDS, median age of 15 years (0-18 years); 42% were male. ECG was performed at time of +UDS on 37 (21%) patients. An abnormal ECG finding was identified in 16/37 (43%), of which 15 had a follow-up ECG. Non-specific similar ECG findings were noted on 3/15: 2 ST segment changes and1 early repolarization. Significant differences were noted on ECGs with +UDS in 12/15 patients, including ST segment changes (4), left ventricular hypertrophy (3), first-degree atrioventricular (AV) block (2), and 1 each: atrial fibrillation, right ventricular hypertrophy, and Mobitz type I second-degree AV block. Conclusions: Abnormal ECG findings, including serious conduction and rhythm disturbances, can be identified in pediatric patients under the influence of marijuana. An ECG should be considered on all patients with a positive urine drug screen for marijuana. DOI: 10.26828/cannabis.2018.01.004