Association of non-cardiac depolarization-blocking drugs with first-registered heart rhythm and survival in out-of-hospital cardiac arrest

OBJECTIVE: Out-of-hospital cardiac arrest (OHCA) is one of the leading causes of mortality worldwide. Survival following OHCA largely depends on whether the initial heart rhythm is shockable or non-shockable. Previous research has suggested that drugs with an off-target effect of blocking cardiac depolarization (non-cardiac depolarization-blocking (DB) drugs) may be associated with a higher likelihood of having a non-shockable rhythm. In this study, we examined whether the use of non-cardiac DB-drugs affects the initial rhythm and survival in OHCA. METHODS: We identified all patients with OHCA of medical causes from the nationwide Danish Cardiac Arrest Registry (2001-2020). Non-cardiac DB-drug use was defined by prescriptions within 90 days prior to OHCA. Multiple logistic regression models with adjustments for relevant confounders were employed to estimate the odds ratio (OR) for the association between non-cardiac DB-drugs and initial heart rhythm and 30-day survival following OHCA. Additionally, stratified analyses were performed based on sex, age, cardiovascular and psychiatric comorbidities, and the year of OHCA occurrence. RESULTS: 1.57, 95 % CI: 1.41-1.74), in the absence of pre-existing psychiatric or non-cardiovascular disease, or when stratified by the year of OHCA occurrence. Finally, we found that users of non-cardiac DB-drugs had lower 30-day survival chances following OHCA when compared to non-users (OR 0.81, 95 % CI: 0.69-0.95). CONCLUSION: Use of non-cardiac DB-drugs was associated with increased odds of non-shockable rhythm in OHCA and with lower 30-day survival following OHCA.