Introduction: The use of cardiac point of care ultrasound (PoCUS) to assess cardiac arrest patients is widespread, although not mandated by advanced cardiac life support (ACLS) guidelines. This study aims to examine if the use of ultrasound is associated with a difference in the length of resuscitation and the frequency of interventions during ACLS in the emergency department (ED). Methods: A retrospective database and chart analysis was completed for patients arriving to a tertiary ED in cardiac arrest, between 2010 and 2014. Patients were excluded if aged under 19, or with a previous DNR order. Patients were grouped based on whether PoCUS was used during ACLS (PoCUS group) and those without PoCUS (control group). Multiple data were abstracted from charts using a standardized form. Data was analyzed for the length of resuscitation, frequency of common ACLS interventions such as endotracheal intubation, administration of epinephrine, and defibrillation, as well as initial cardiac activity findings on PoCUS. Results: 263 patients met the study inclusion criteria, with 51 (19%) in the control group, and 212 (81%) in the PoCUS group. In the PoCUS group 23 (11%) had cardiac activity (Positive PoCUS) and 189 (89%) had no cardiac activity recorded. Positive PoCUS patients had longer mean resuscitation times (26.13 min, 95% CI 17.80-34.46 min) compared to patients with no PoCUS cardiac activity (12.63 min, 95% CI 11.07-14.19 min, p < 0.05) as well as to the control group (14.20 min, 95% CI 10.30-18.09 min, p < 0.05). Positive PoCUS patients were more likely to receive endotracheal intubation (91%, 95% CI 72-99%), and epinephrine (100%, 95% CI 85-100%) than patients with no PoCUS cardiac activity (ET: 47%, 95% CI 40-54%, p < 0.0001; Epi: 81%, 95% CI 75-86%, p < 0.0172) and than the control group (ET: 65%, 95% CI 50-78%, p < 0.0227; Epi: 80%, 95% CI 67-90%, p < 0.0258). There was no difference in numbers receiving defibrillation between groups. Conclusion: Our results suggest emergency physicians may be making increased resuscitative effort for patients with positive cardiac activity findings on PoCUS compared to those with negative findings or when no PoCUS was performed.