Heart Failure

Mild heart failure initially only manifests itself as exercise intolerance but as the disease progresses the symptoms gradually worsen. In advanced heart failure, the symptoms are debilitating leading to a very poor quality of life.

The New York Heart Association (NYHA) has classified heart failure into four categories based on the severity of the symptoms:



Class I


No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, or shortness of breath.

Class II


Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in fatigue, palpitation, or shortness of breath

Class III (Moderate)

Marked limitation of physical activity. Comfortable at rest, but less than ordinary activity causes fatigue, palpitation, or shortness of breath

Class IV (Advanced)

Unable to carry out any physical activity without discomfort. Symptoms of cardiac insufficiency at rest. If any physical activity is undertaken, discomfort is increased.


The prognosis for heart failure generally is very poor and, for advanced heart failure, the prognosis is nearly always terminal. The terminal prognosis and very poor quality of life mean that advanced heart failure is a particularly unpleasant condition.

One of the main reasons heart failure is so difficult to treat is a fundamental mal-adaptation made by the body in response to the onset of heart failure: a healthy heart’s left ventricle pumps oxygenated blood into the aorta and throughout the body until it returns to the right ventricle from which it is pumped into the lungs for re-oxygenation, but, if one of the ventricles is not working properly the blood is not circulated effectively.  In these circumstances, the muscle in the failing ventricle tends to expand and becomes thinner in an effort to supply adequate blood flow but this in fact makes it harder for the heart to contract effectively and results in even lower flow, increased effort and further expansion of the ventricle.

This vicious circle of expansion is very difficult to break without completely relieving the strain on the heart, which of course is very difficult as the heart cannot stop to rest.

The traditional heart failure treatments of drugs (medical management) and pacemakers (cardiac resynchronization therapy) are mostly unable to break this cycle in advanced heart failure. Heart transplantation is an effective treatment for advanced heart failure but is severely limited by the availability of donor hearts.

Ventricular assist devices (VADs) have been shown to break the vicious cycle of heart failure: they have been demonstrated to restore adequate perfusion and relieve the strain on the ventricular muscle.

Find out more:

Facts and figures

Traditional treatments

VAD therapy

Disclaimer: Calon Cardio’s VAD devices are not available for sale, including in the United States of America