Body circulation of Blood is mainly controlled by the heart and its coordinated contractions. In brief, the well oxygenated blood returns to the heart through the left atrium and shunted through a valve to the left ventricle. Due to the coordinated contractile action of the heart musculature the blood in the left ventricle pumps through the aortic artery to the entire body. The oxygen depleted blood from the rest of the body arrives in the right atrium through the great vessels and passed on to the right ventricle where it forcefully shunted towards the lungs for oxygenation. The cycle is absolutely vital for the body to function and any disruption will result in catastrophe.

When the heart is unable to perform its function in pumping the blood according to the body requirements it is said to be in a state of 'failure'. Heart Failure is classified more commonly as left heart failure and right heart failure and is a chronic progressive condition which can occur due to several reasons:

Coronary artery disease: Where the vessels supplying blood to the heart musculature is blocked and fails in performing its task

High blood pressure: Which increase the pressure against in which the heart should be pumped.

Diabetes: will lead to arterial disease as well as other complications in the musculature

The above list is never a complete one and would be a long one if all the causes are mentioned.

At the beginning the symptoms of heart failure will be masked and compensatory mechanisms will take over. They are:

Enlarging of the heart chambers: according to the body physics the enlarging of the heart chambers will allow them to pump more blood much more strongly.

Increase muscle mass: the heart muscle size and amount will increase to a restrictive type of stress towards the heart and will allow the heart to pump stronger than usual against this resistance.

Faster contractility: the idea is to pump more blood and mask the limitations occurring due to limited amount of blood entering the circulation. The blood vessels become narrower and would try to maintain pressure to compensate the heart function. The blood will be directed towards the more vital organs (e.g. brain, kidneys, etc) to maintain body function with the limited amount of effective blood.

Although at the beginning the compensatory mechanisms are successful in masking the disease process, gradually the reality takes its turn. These mechanisms will be exhausted and would no longer be able to compensate, thus gives rise to the heart failure symptoms and can be due to several reasons;

An increased amount of blood will be collected in the vessels in the lungs which gives rise to fluid leak in to the lung tissue. Thus the patient will experience difficulty in breathing and moreover orthopnoea as more fluid gets accumulated when the patient is lying down. The blood returning from the body will not be able to get into the right atrium due to the enormous pressure and thus gets collected in the dependent parts of the body, mainly, ankle, legs and back area if the patient is mostly bed-ridden. The swelling of these areas will be increasingly evident and is called oedema.

The patients are treated by correcting the underlying conditions and medications which supports the functioning of the heart. When all these treatment options fail, the only remaining option would be for a heart transplant.