Cannabis users with ischemic heart disease had significantly more nonsustained ventricular tachycardia (47.8%) than healthy cannabis users (5.6%), though overall arrhythmia burden did not differ from non-cannabis-using heart patients.
Read this if you use cannabis and have a history of heart disease, or if you are a cardiologist advising patients about cannabis.
47.8% vs 5.6%Nonsustained ventricular tachycardia prevalence in ischemic heart disease vs healthy cannabis users
What the researchers found
Among cannabis users wearing 14-day heart monitors, healthy controls showed brief heart rate increases (~5 bpm at 20 min) that declined after 4 hours. In ischemic heart disease (IHD) subjects, heart rate changes were blunted. Supraventricular tachycardia was most common in controls (9.5%) while nonsustained ventricular tachycardia dominated in IHD subjects (47.8% vs 5.6% in controls). SVT incidence decreased with more cannabis use in both groups. NSVT tended to increase with use in controls and was more prevalent in IHD. However, overall arrhythmia burden did not differ between cannabis users and non-users with IHD.
Why it matters
Cannabis use is increasing among older adults who are more likely to have heart disease. This is the first prospective study specifically examining arrhythmia risk in cannabis users with established ischemic heart disease.
The numbers in context
- Controls: n=37 (57% men); IHD cannabis users: n=24 (58% men); IHD non-users: n=35 (51% men)
- 14-day Zio monitor wear
- HR increase: 4.99±6.7 bpm at 20 min in controls
- HR decline: -7.4±7.7 bpm at 4h (p<0.05 in IHD)
- NSVT: 47.8% in IHD vs 5.6% in controls (p=0.01)
- SVT: 9.5% in controls vs 4.2% in IHD (p=0.04)
How the study worked
Prospective observational study. Cannabis-using healthy controls and IHD subjects wore Zio monitors for 14 days. Non-cannabis-using IHD patients as additional comparator. Heart rate changes correlated with cannabis consumption timing. Arrhythmia frequency tracked.
Who was studied
37 healthy cannabis users, 24 ischemic heart disease cannabis users, 35 IHD non-users
What this study cannot tell us
Small sample sizes. Observational design. Self-reported cannabis use timing. IHD non-user group wore monitors for clinical indications (potential selection bias). Cannabis use amount and method not standardized.
How to read the evidence
Prospective observational study with objective continuous cardiac monitoring. Small but provides first systematic data on this specific question.
When this study was published
Published in 2023. First prospective study of cannabis-associated arrhythmias in ischemic heart disease.
The bigger picture
The finding that NSVT is dramatically more common in cannabis users with heart disease warrants attention, even though the overall arrhythmia burden was not different from non-using heart patients. NSVT can progress to dangerous ventricular tachycardia.
Questions still open
- Should cannabis users with IHD be monitored more closely for ventricular arrhythmias?
- Does the type of cannabis (THC vs CBD) differentially affect arrhythmia risk in IHD?
- Would larger studies show increased mortality from cannabis-associated arrhythmias in IHD?
Read the original research
Arrhythmic Effects of Cannabis in Ischemic Heart Disease.
Cannabis and cannabinoid research, 8(5), 867-876
Citation
Gillett, Leah; Johnson-Sasso, Cecelia; Miller, Brian; Shakowski, Courtney; Walker, Lori A; Tompkins, Christine. (2023). Arrhythmic Effects of Cannabis in Ischemic Heart Disease.. Cannabis and cannabinoid research, 8(5), 867-876. https://doi.org/10.1089/can.2021.0188