The arrhythmic effects of Cannabis – a single center experience

Background: The use of cannabis is increasing worldwide. Previous studies in healthy volunteers showed pro-arrhythmic effects with a biphasic and dose-dependent effect. At low-moderate doses sympathetic activation dominates, whereas at high doses the parasympathetic activation increases. We aimed to describe our experience with cannabis-related arrhythmias.

Methods: We revised all arrhythmia-related hospitalizations in our center during 11/2017 - 11/2019 and describe the clinical characteristics of the cannabis-related ones.

Results: Three cases were identified: 1) A 30 yo male with daily marijuana usage, presented with palpitations. He had normal ECG, echocardiography and blood tests. During two successive stress tests he developed polymorphic VT that had converted to SVT during recovery phase. cMRI and coronary catheterization were normal. EPS was negative for sustained VT but SVT was easily induced with spontaneous recurrent conversions to atrial flutter and atrial fibrillation, thus no ablation therapy was issued. Selective beta blockers eliminated the arrhythmias with normal recurrent stress tests during follow-up of 2 months; 2) Another 30 yo male with occasional cocaine usage but regular marijuana smoking presented with palpitations, chest pain and dizziness that improved during efforts. First ECG showed CAVB, thereafter atrial flutter with normal AV conduction occurred. Then Mobitz 1 second degree AVB appeared and was followed by atrial flutter after physical effort. The patient was discharged after normal echo, blood tests and recurrent stress test, but was lost to follow up; 3) A 24 yo male, smoking marijuana twice a week, presented with two episodes of syncope. The ECG showed low atrial rhythm. Baseline examinations were normal. The patient was implanted with ILR that furtherly detected frequent asymptomatic episodes of bradycardia

Conclusions: Cannabis-related arrhythmias tend to be multiform. Thus, presentation of “odd” combinations of arrhythmias should raise a suspicion of cannabis use. In this era of increasing usage of cannabis, people should be aware of its potential malignant side-effects.