Difference between atrial and ventricular fibrillation

Introduction

A Fibrillation, whether atrial or ventricular in origin, is an abnormality in heart rate and rhythm. This is medically known as a cardiac arrhythmia and usually, lasts barely for 2-3 seconds. They are common, often harmless, but can reflect an underlying heart disease and shouldn’t be ignored. They are often intermittent, thus, difficult to diagnose. Occasionally, they are severe causing a cardiac compromise.

What is fibrillation?

If there is lack of coordination in the heart rate and rhythm, it leads to the pumping of the chambers going out of sync. As a result, there will be severe compromise on the amount of blood reaching various parts of the body, which can be fatal. If fibrillation occurs in either of the heart’s upper two chambers, it is known as atrial fibrillation and if it occurs in any of the two lower chambers it is known as ventricular fibrillation.

Atrial fibrillation is a series of excessive, abnormal contractions of the atria due to which the blood does not get effectively pumped to the ventricles. This results in blood getting accumulated in the atria. Due to this, the lower chambers get over-stimulated and try to compensate; the heart rate increases to about 300-600 beats per minute during atrial fibrillation.

Ventricular fibrillation occurs when there are rapid, unchecked contractions of the ventricles at over 120 bpm. These contractions replace normal ventricular contractions and put the pumping out of order. Due to this fibrillation, effective contraction does not occur and blood is not pumped as a result of which the blood pressure starts dropping.

Difference in causation

Atrial fibrillation causes are often unknown and usually an incidental finding. Patients often have no symptoms. Common causes are high blood pressure, coronary heart disease and infections like pneumonia etc.

Ventricular fibrillation usually happens to people with a prior history of heart attack. Thus, this condition is always due to some underlying heart disease or damage to heart tissue.

Difference in the way they affect the body

Typically, atrial fibrillation is not life threatening but if neglected over a period of time it can prove dangerous. The most common complication is stroke which occurs due to a blood clot formation that travels. This occurs due to slow blood flow which results in clotting of blood which can get dislodged and reach the brain, block a small blood vessel there and lead to paralysis.

Ventricular fibrillation is a life-threatening emergency as the ventricles of the heart are no longer pumping blood to the body which leads to sinking of blood pressure. This can result in fainting and even a sudden fatal cardiac arrest.

Difference in treatment

The treatment for atrial fibrillation mainly depends upon the age of the patient, the cause and the intensity of atrial fibrillation. Medicines such as blood thinners can be taken to prevent clots and stroke. Medicines like Beta blockers, verapimil and amiodaraone are prescribed to reduce atrial fibrillation.

The only way to rectify a heart that is experiencing ventricular fibrillation is to give an electrical shock by a process called as Defibrillation.  This stimulates the heart to return to its normal rhythm and rate. This is done by a medical device called a defibrillator which should be used in time.

Summary

Atrial and ventricular fibrillation are conditions of discordant heart beat, excessive rate and rhythm. This occurs as some part of the heart stops contracting resulting in a compromise in the blood flow to the body and within the heart. Atrial fibrillation is generally not an emergency situation and can be treated with medications but should not be neglected. Ventricular fibrillation happens due to some underlying heart disease and can be fatal if ignored.