Ventricular Repolarization in Healthy Young Adults Who Use Combusted Cannabis: A Cross-Sectional Parallel Group Comparison Study.

Background: Inhaled combusted cannabis and co-use of combusted cannabis and nicotine electronic cigarettes (ECIGs) are emerging trends among young adults, yet the potential cardiovascular disease risks associated with these substances remain unclear. This study examined whether cannabis use increases cardiovascular disease risk, specifically, arrhythmia risk, as estimated by ventricular repolarization, and whether ECIG co-use further amplifies this risk.

Methods: A cross-sectional parallel group comparison study was conducted with 3 groups: healthy adults (21-30 years) who (1) chronically use combusted cannabis but no tobacco, (2) chronically co-use both nicotine ECIGs and combusted cannabis, and (3) are nonusers (controls). The primary outcomes, Tpeak-Tend (Tp-e) interval, Tp-e/QT, and Tp-e/QTc, were assessed using 5-minute ECG recordings during supine rest and abrupt standing. Secondary outcomes included resting hemodynamic parameters and heart rate variability.

Results: The study enrolled 134 participants (cannabis use=59, cannabis/ECIG co-use=26, control=49). The demographics among the groups did not differ. At supine rest, the Tp-e interval was not different between the combusted cannabis users (88±18 milliseconds) and controls (91±20 milliseconds; P=0.68). In contrast, the Tp-e was significantly shorter in the cannabis/ECIG co-use group (77±15 milliseconds) compared with the cannabis (P=0.017) and control (P=0.003) groups. These findings were confirmed upon abrupt standing. Hemodynamic and heart rate variability parameters did not differ among groups.

Conclusions: In healthy young adults, chronic co-use of inhaled combusted cannabis and nicotine ECIGs, but not exclusive cannabis use, is associated with alterations in ventricular repolarization as estimated by Tp-e. The implications of short ventricular repolarization in people who co-use nicotine ECIGs and inhaled combusted cannabis warrant further investigation.