Introduction: Left and right atrial volume indices (LAVI and RAVI) are markers of cardiac remodeling. LAVI and RAVI are associated with worse outcomes in other cardiac conditions. This study aimed to determine the association of LAVI and RAVI with survival time post-cardiac arrest. Hypothesis: Atrial volumes are associated with survival time post-cardiac arrest. Methods: This was a single center, retrospective study of patients with a cardiac arrest event during index hospitalization from 2014-2018. LAVI was calculated using the biplane Simpson’s method, while RAVI was calculated using a single plane summation in the 4-chamber view. Patients were further stratified into either having a Vfib/pulseless VT (pVT) event or a PEA arrest/asystole event. Survival time was measured in days from event to death date. Kaplan-Meier plots were used to evaluate differences in survival time for patients based on mean LAVI and RAVI. Results: Of 305 patients studied (64 +/- 14 years, 37% female (112 out of 305)), 162 had a reliable LAVI measurement with a mean of 34.1 mL/m 2 (SD=15.8) and 163 had a reliable RAVI measurement with a mean of 25.1 mL/m 2 (SD=15.5). In patients who had sustained a VFib/pVT event, those with reduced LAVI (p=0.045) and RAVI (p=0.041) values below the mean had significantly improved survival time. No association was found in the PEA/asystole subgroup. KM plots of patient survival for both LAVI and RAVI compared to mean are presented in figures 1a and 1b. Conclusion: Among patients presenting with Vifb/pVT arrest, increased LAVI and RAVI were associated with decreased survival time. More studies are needed to better prognosticate cardiac arrest using atrial volumes.