Written by Chris Thom
Spoon Feed
In this multicenter trial of patients presenting to the ED after out-of-hospital cardiac arrest (OHCA), 5.3% were found to have occult ventricular fibrillation (VF) on point-of-care echocardiography.
Sometimes we should shock asystole?
This prospective trial included 28 EDs and enrolled 811 adult patients with OHCA with resuscitation ongoing upon ED arrival. Eligible patients were those with at least one simultaneous bedside echo and ECG during any of the initial 3 pauses in CPR. Experts then reviewed the echo images and ECG tracing at a later date.
5.3% of patients were found to have occult VF on echo, with 81.4% demonstrating PEA on the ECG tracing and 18.6% having asystole on ECG tracing. Patients with ECG VF were more likely to receive defibrillation than those with occult VF on echo (54% vs. 30.2%). Patients with occult echo VF had survival to hospital discharge of 7.0%, versus only 5.4% with ECG VF (OR 3.6, 95%CI 0.63-19.19).
How will this change my practice?
This is by far the largest and most comprehensive study to date on occult VF and is a key value-add for bedside echo in cardiac arrest. If 5.3% of our asystole or PEA patients actually have occult VF warranting defibrillation, that should raise our eyebrows and probably change our practice. Perhaps we need to find a way to add “occult VF on echo” to the Hs and Ts that we all memorize from ACLS.
POCUS pro tips and clips
The choice of window is often patient dependent. The parasternal long (PSLA) will often give better views than the subcostal window, but it can get in the way of chest compressions and is poorly accessible with mechanical compression devices. I’ll try to obtain the subcostal window first and then consider PSLA if the subcostal is inadequate. VF on echo will appear as fibrillatory activity of the myocardium. This is a constant and ongoing “quivering” of the actual myocardial walls (see below video of a TEE image where VF is converted to an organized rhythm following defibrillation).
Source
Incidence and Clinical Relevance of Echocardiographic Visualization of Occult Ventricular Fibrillation: A Multicenter Prospective Study of Patients Presenting to the Emergency Department After Out-of-Hospital Cardiac Arrest. Ann Emerg Med. 2025 Oct;86(4):328-336. doi: 10.1016/j.annemergmed.2025.04.014. Epub 2025 Jun 30. PMID: 40590825.
