Author: Aaron Lessen, M.D. Educational Pearls: There is currently debate within the medical community about what constitutes cardiac activity on ultrasound in the setting of cardiac arrest. A recent study has shown there providers looking at the same clips from an echo will disagree about what constitutes cardiac activity. Some of the confusion stems from movement that is not cardiac in etiology. For example, some alvular movement can be due to IV fluids and some cardiac motion can be due to the patient being bagged. Cardiac activity is defined as “Any intrinsic motion of the myocardium.” However, even if this is present, it is important to ask if it clinically significant cardiac activity. Despite disagreement, ultrasound can be useful for clinical decision making.   References: Gaspari R et al. (2016) Emergency Department Point-Of-Care Ultrasound in Out-Of-Hospital  and in-ED Cardiac Arrest. Resuscitation; 109: 33 – 39. Hu K et al. (2017) Variability in Interpretation of Cardiac Standstill Among Physician Sonographers. Ann Emerg Med.