Ventricular fibrillation

At the time of the event, the patient becomes unconscious and unresponsive. Symptoms that may precede this are:

Chest pain
Shortness of breath
Nausea
Vomiting
Action should be taken to save the patient, or he will die in a few minutes.

The Patient should be transferred to the hospital immediately, and should follow up with a Cardiologist afterwards

Several risk factors may contribute to ventricular fibrillation development:

Heart disease in which there’s low blood flow to the heart due to the narrowing of the heart’s blood vessels
Heart muscle disease
Structural heart disease
Previous cardiac arrest
Genetic diseases (ex: congenital valvular diseases)
Electrolyte imbalance (ex: Potassium, Magnesium)
Drug abuse (ex: Cocaine, Methamphetamine)
Medications side effects (Ex: Amiodarone, Sotalol)
Sepsis
Brugada-syndrome

The main diagnosis is done through the symptoms and electrocardiogram.

Electrocardiogram (a simple test to examine the rhythm and electrical activity of the heart using skin-attached sensors to detect the electrical signals produced by the heart during each beat).
Laboratory tests (a blood sample is used to measure the levels of specific cardiac enzymes to help in diagnosis in addition to measuring the level of potassium and magnesium).
Echocardiogram (a type of ultrasound scan that is used to examine the heart valves and how it pumps blood to the body). This is used in this case to know if there’s structural heart disease.
Computed tomography “CT” (an imaging technique in which several images are taken to get a detailed picture of the heart).
Magnetic resonance imaging “MRI” (an imaging technique that uses magnetic waves to get a detailed image of the heart to diagnose any other existing heart disease that causes this condition).
Coronary angiography (a test that uses x-ray imaging to examine if there’s a narrowing in the heart’s blood vessels).

Emergency:

Cardiopulmonary resuscitation “CPR”: A life-saving procedure during cardiac arrest, it’s done by chest compressions to make the heart beat again and by giving the patient rescue breaths if needed.
Cardioversion: A procedure in which patches on the chest are used to give the heart an electric shock to restore normal heartbeat rhythm.
Medications: Adrenaline and Amiodarone can be used after the cardioversion.
Long-term:

Medications: The Cardiologist may prescribe Amiodarone for long-term use to prevent this condition.
Implantable cardioverter-defibrillator: A small device implanted under the skin to give an electric shock to return to the normal rhythm of heartbeats if the heart rhythm was disturbed.
Cardiac ablation: A procedure in which radiofrequency is used to make small scars in the heart tissues that cause extra electric signals and beats.