Abstract 14914: Sudden Cardiac Arrest Manifesting With Shockable vs. Non-Shockable Rhythms
Introduction: Sudden cardiac arrest (SCA) presenting with non-shockable rhythms (pulseless electrical activity or asystole) has a significantly higher mortality than shockable rhythms (ventricular fibrillation/tachycardia, VF/VT). We hypothesized that cases with non-shockable rhythms have distinctive demographic and clinical characteristics compared to shockable rhythms.
Methods: Cases of out-of-hospital SCA (age ≥18 years) with resuscitation attempted by first responders were identified from a large ongoing population-based study in a Northwest US metro area (population approx. 1 million). Cases were identified prospectively and confirmed by a process of in-house adjudication. Presenting arrhythmia was identified from review of first responder reports and electrocardiographic recordings. Logistic regression was used to evaluate significant factors associated with non-shockable rhythms.
Results: A total of 758 cases (47%) presented with shockable and 855 (53%) with non-shockable rhythms (25% asystole, 28% pulseless electrical activity).The non-shockable group was older, more likely to be female, less likely to be witnessed, to have bystander CPR and return of spontaneous circulation (all p≤ 0.0005) with much lower survival rates (3% vs. 23%, p< 0.0001). After adjustment for age and arrest circumstances, female gender [OR 1.69 (95% CI 1.26-2.27)], history of respiratory disease [OR 1.44 (95% CI 1.01-2.06)], use of antipsychotic medication [OR 2.04 (95% CI 1.17-3.54)] and beta-2 agonists [OR 1.59 (95% CI 1.05-2.42)] were significant factors associated with non-shockable rhythms. Coronary artery disease was less common in this group [OR 0.42 (95% CI 0.32-0.54)]. In a subset (n= 283) with available EKG and echocardiograms, higher resting heart rate [OR for 10 bpm increase 1.22 (95% CI 1.03-1.46)] and preserved ejection fraction (≥50%) [OR 3.08 (95% CI 1.66-5.71)] were also associated with non-shockable SCA.
Conclusion: These findings suggest that subjects with SCA and a non-shockable rhythm may be distinguishable from those with shockable rhythms, with potential implications for SCA mechanisms and management.
- © 2013 by American Heart Association, Inc.