Ventricular fibrillation: Ventricular fibrillation (VF) is a very fast rhythm of the heart in which heart stops contracting effectively. It is equivalent to cardiac arrest and death, unless promptly treated by chest compression and rescue breaths (cardiopulmonary resuscitation or CPR). It is the most dreaded heart rhythm disorder.

Can you know if you are having ventricular fibrillation?

No. You will lose consciousness soon after the heart goes into ventricular fibrillation. Only nearby persons can help you by starting CPR immediately or at least by calling for expert help.

How is ventricular fibrillation corrected?

Some cases of VF may be transient and normal rhythm may resume soon after CPR is initiated. But this is usually rare and VF has to be corrected by an electrical shock using a device known as defibrillator. Defibrillator is a sophisticated medical equipment which can be used only by a trained medical person. But there is another similar device known as automatic external defibrillator (AED) which can be used by a lay person with minimal training. This device has automatic rhythm analysis and prompts action by recorded voice when you switch it on. AEDs are being widely deployed in public places where large number of persons are likely to gather like airports, bus stations, railway stations and malls.

What are the important diseases which can cause ventricular fibrillation?

Any type of heart disease can lead to VF if it is severe enough. But most commonly VF occurs in the early hours after a heart attack. That is why any person with significant chest pain should seek early medical attention. This is also the reason why you are supposed to travel in an ambulance when you have severe chest pain rather than drive your own vehicle, which can be catastrophic. Ambulance gets priority on the road as well as on arrival at the hospital.

Abnormalities in blood electrolytes like low potassium and magnesium levels can lead on the VF. Some medications in toxic levels (high doses) can cause VF. There are some primary inherited electrical disorders of the heart in which one is prone for ventricular fibrillation. Most of these have some special features on the ECG.

How is ventricular fibrillation detected?

When a person collapses with VF, medical team attaches a heart rhythm monitor which will show the live ECG (electrocardiogram) tracing. VF is diagnosed from the pattern on the monitor by the trained person. Occasionally VF gets recorded on the ECG when the person develops VF while the ECG is being recorded. But this is very rare. VF may also be documented on heart rhythm monitors – either external or implanted – which have been already attached when the event occurs. There are implantable devices known as implantable defibrillator cardioverter (ICD) which can detect VF and automatically treat it by delivering a shock. These expensive devices are implanted in those who are known to be very prone for VF.