The basic function of the heart is to pump the blood which is then circulated to the entire body. Heart failure occurs when the heart fails to pump enough blood to meet the body’s needs. 

Now a days heart failure has become a common ailment across the globe and is the root cause of many heart-related diseases.

Most common causes of heart failure:-

• Blockage of the arteries (coronary heart disease).
• Heart attack.
• High blood pressure.
• Heart valve problems.
• Diabetes.
• Lung diseases.
• Genetic problems in the heart muscles.
• Heart infections.
• Excessive intake of alcohol.

Cardiac resynchronization therapy (CRT), also called biventricular pacing, uses a special kind of pacemaker (a biventricular pacemaker) that is designed to help the ventricles contract more normally. 

The procedure involves implanting a half-dollar sized pacemaker, usually just below the collarbone. A biventricular pacemaker monitors the heart rate to detect heart rate irregularities and emit tiny electrical impulses to both of the heart's lower chambers (the left and right ventricles) so that they pump in a more efficient, coordinated manner. In effect, it is "resynchronizing" the heart.

A CRT system is made up of two parts. 

• The heart device, which is actually a tiny computer, plus a battery, contained in a small titanium metal case that is about the size of a pocket watch.
• Insulated wires, called leads, that are implanted to carry information signals from your heart to the heart device and to carry electrical impulses to your heart

This therapy has been shown to improve the symptoms of heart failure and overall quality of life in certain patients with severe symptoms that aren't controlled with medication.