A mechanical failure of the heart causes cardiac asthma and this may turn out to be fatal if not diagnosed promptly. During a typical cardiac asthma attach, the heart cannot pump enough blood around the body as effectively as it normally does. Because of this fluid and other chemical substances build up inside the air passages in the lungs. This results in a congestion of these airways and hence makes breathing much harder.

Cardiac asthma takes place when one side of the heart cannot keep up with its workload, or to be more exact, when its pumping capacity is exceeded by the amount of blood needed. When this condition persists and is not met with proper treatment and medication - the result is a possible heart failure caused by a stoppage of the pulmonary circulation - as the heart can no longer pump sufficient blood throughout the body.

It is important to note the differences between the causes of cardiac asthma and usual asthma. The treatment applied to cardiac asthma and normal asthma differs, and without sufficient knowledge one may not know how to handle such potentially life-threatening situations.