Ventricular fibrillation (V-fib) is a dangerous type of arrhythmia, or irregular heartbeat. It affects your heart’s ventricles. Your heart is a muscle system that contains 4 chambers; the 2 bottom chambers are the ventricles. In a healthy heart, your blood pumps evenly in and out of these chambers …
https://www.hopkinsmedicine.org/health/conditions-and-diseases/ventricular-fibrillation