Background
There has been no previous thorough toxicological examination of a cohort of patients with resuscitated sudden cardiac arrest. We aimed to determine the qualitative and quantitative drug composition in a resuscitated sudden cardiac arrest population, using forensic toxicology, with focus on prescribed, non-prescribed, and commonly abused drugs.

Methods
Individuals aged 18–90 years with resuscitated sudden cardiac arrest of presumed cardiac causes were prospectively included from a single tertiary center. Data from the sudden cardiac arrest hospitalization was collected from medical reports. Drugs used during resuscitation or before the blood sampling were identified and excluded in each patient. Mass spectrometry-based toxicology was performed to determine the absence or presence of most drugs and to quantify the findings.

Results
Among 186 consecutively enrolled resuscitated sudden cardiac arrest patients (median age 62 years, 83% male), 90% had a shockable rhythm, and were primarily caused by ischemic heart disease (66%). In total, 90 different drugs (excluding metabolites) were identified, and 82% of patients had at least one drug detected (median of 2 detected drugs (IQR:1–4)) (polypharmacy). Commonly abused drugs were present in 16%, and QT-prolonging drugs were present in 12%. Polypharmacy (≥5drugs) were found in 19% of patients. Importantly, none had potentially lethal concentrations of any drugs.

Conclusion
In resuscitated sudden cardiac arrest patients with cardiac arrest of presumed cardiac cause, routine toxicological screening provides limited extra information. However, the role of polypharmacy in sudden cardiac arrest requires further investigation. No occult overdose-related cardiac arrests were identified.