Cardiac asthma is a medical symptom, of wheezing, coughing or shortness of breath which may be due to congestive heart failure. It is known as cardiac asthma because the symptoms may mimic asthma. One study found one third of all patients involved who have symptoms of cardiac asthma also have congestive heart failure.
Depending on the severity of the symptoms, it can be classified as a medical emergency as it is a symptom of heart failure leading to the build up of fluids in the lungs-pulmonary edema and in and around the airways.
Asthma is very different in this sense as true asthma is caused by the inflammation and eventual narrowing down of airways. This is what causes the breathing difficulties that is characteristic to asthma.
Asthma has nothing to do with fluid in the lungs or heart disease or even heart failure which is so associated with Cardiac Asthma.
The Distinction between true asthma and cardiac asthma is especially important because using treatments for true asthma including inhalers( in the assumption that the child actually has Asthma) may actually worsen cardiac asthma and cause severe heart rhythmic issues.
Read more about Cardiac Asthma: Popular Culture