Clinical predictors of shockable versus non-shockable rhythms in patients with out-of-hospital cardiac arrest.
To identify factors associated with a non-shockable rhythm as first recorded heart rhythm.



Patients ≥18 years old suffering out-of-hospital cardiac arrest between 2001 and 2012 were identified in the population-based Danish Cardiac Arrest Registry. Danish administrative registries were used to identify chronic diseases (within 10 years) and drug prescriptions (within 180 days). A multivariable logistic regression model, including patient related and cardiac arrest related characteristics, was used to estimate odds ratios (OR) for factors associated with non-shockable rhythm.



A total of 29,863 patients were included: 6600 (22.1%) patients with a shockable rhythm and 23,263 (77.9%) patients with a non-shockable rhythm. A non-shockable rhythm was associated with female gender, arrest in private home, unwitnessed arrest, no bystander CPR, and longer time to first rhythm analysis compared to patients with shockable rhythm. In the adjusted multivariable regression model, pre-existing non-cardiovascular disease and drug prescription were associated with a non-shockable rhythm e.g. chronic obstructive lung disease (OR 1.44 [95% CI: 1.32-1.58]); and the prescription for antidepressants (OR 1.49 [95% CI: 1.35-1.65]), antipsychotics (OR 2.30 [95% CI: 1.96-2.69]) analgesics (OR 1.32 [95% CI: 1.23-1.41]), corticosteroids (OR 1.64 [95% CI: 1.44-1.85]), and antibiotics (OR 1.59 [95% CI: 1.40-1.81]). In contrast, the prescription of cardiovascular drugs and a history of cardiovascular disease e.g. ischemic heart disease was associated with a lower risk of non-shockable rhythm (OR 0.66 [95% CI: 0.60-0.71]).



This study demonstrate that non-cardiovascular disease and medication prescription are associated with a non-shockable rhythm while cardiovascular disease and medication prescription are associated with a shockable rhythm as first recorded rhythm in patients with OHCA.
Department of Anesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark. Electronic address: granfeldt@gmail.com.
Asger
A
Granfeldt
Emergency Medical Services Copenhagen, University of Copenhagen, Copenhagen, Denmark; Department of Cardiology, Copenhagen University Hospital Gentofte, Hellerup, Denmark.
Mads
M
Wissenberg
Department of Clinical Epidemiology, Aalborg University Hospital, Aalborg, Denmark.
Steen Møller
SM
Hansen
Emergency Medical Services Copenhagen, University of Copenhagen, Copenhagen, Denmark.
Freddy K
FK
Lippert
Prehospital Emergency Medical Services, Southern Denmark Region, Denmark.
Torsten
T
Lang-Jensen
Prehospital Emergency Medical Services, Zealand Denmark Region, Denmark.
Ole Mazur
OM
Hendriksen
Institute of Health, Science and Technology, Aalborg University, Denmark.
Christian
C
Torp-Pedersen
Prehospital and Emergency Medical Services, North Denmark Region, Aalborg, Denmark; Clinical Institute, Aalborg University, Aalborg, Denmark; Department of Anesthesiology, Aalborg University Hospital, Aalborg, Denmark.
Erika Frischknecht
EF
Christensen
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
Christian Fynbo
CF
Christiansen
D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000706:statistics & numerical data*; D002908:Chronic Disease; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004554:Electric Countershock / Q000706:statistics & numerical data; D004632:Emergency Medical Services / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000209:etiology / Q000401:mortality* / Q000628:therapy; D011159:Population Surveillance; D055553:Prescription Drugs / Q000009:adverse effects*; D012042:Registries; D012737:Sex Factors; D016019:Survival Analysis; D061665:Time-to-Treatment; D016896:Treatment Outcome
D055553:Prescription Drugs
Arrhythmias; Cardiac comorbidities; Cardiopulmonary resuscitation; Cardiopulmonary resuscitation/epidemiology; Cardiopulmonary resuscitation/pharmacology; Out-of-hospital cardiac arrest