Ventricular fibrillation

Ventricular fibrillation
12-lead ECG showing ventricular fibrillation
Specialty	Cardiology, Emergency Medicine
Symptoms	Cardiac arrest with loss of consciousness and no pulse[1]
Causes	Coronary heart disease (including myocardial infarction), valvular heart disease, cardiomyopathy, Brugada syndrome, electric shock, long QT syndrome, intracranial hemorrhage[2][1]
Diagnostic method	Electrocardiogram[1]
Differential diagnosis	Torsades de pointes[1]
Treatment	Cardiopulmonary resuscitation (CPR) with defibrillation[3]
Prognosis	Survival rate 17% (out of hospital), 46% (in hospital)[4][5][1]
Frequency	~10% of people in cardiac arrest[1]

Ventricular fibrillation (V-fib or VF) is an abnormal heart rhythm in which the ventricles of the heart quiver.^[2] It is due to disorganized electrical activity.^[2] Ventricular fibrillation results in cardiac arrest with loss of consciousness and no pulse.^[1] This is followed by sudden cardiac death in the absence of treatment.^[2] Ventricular fibrillation is initially found in about 10% of people with cardiac arrest.^[1]

Ventricular fibrillation can occur due to coronary heart disease, valvular heart disease, cardiomyopathy, Brugada syndrome, long QT syndrome, electric shock, or intracranial hemorrhage.^[2][1][6] Diagnosis is by an electrocardiogram (ECG) showing irregular unformed QRS complexes without any clear P waves.^[1] An important differential diagnosis is torsades de pointes.^[1]

Treatment is with cardiopulmonary resuscitation (CPR) and defibrillation.^[3] Biphasic defibrillation may be better than monophasic.^[3] The medication epinephrine or amiodarone may be given if initial treatments are not effective.^[1] Rates of survival among those who are out of hospital when the arrhythmia is detected is about 17% while in hospital it is about 46%.^[4][1]