Ultrasound detection of ventricular fibrillation disguised as asystole.

Ultrasonography in the emergency department is being used for many purposes, including the evaluation of patients with cardiac arrest. Ultrasound testing has been shown to be useful in such patients in determining the presence of true electromechanical dissociation and pericardial effusions. We report a case of ventricular fibrillation identified by ultrasonography that appeared as asystole on ECG monitoring. Recognition of this ultrasound application can aid in the prompt diagnosis of occult ventricular fibrillation and allow for proper treatment with defibrillation.