Cardiac asthma is a medical diagnosis of wheezing, coughing, dyspnea, bloody sputum, or shortness of breath due to congestive heart failure.
It is known as cardiac asthma because the symptoms mimic ordinary asthma (bronchial asthma). One study found that patients with cardiac asthma represented one third of congestive heart failure in elderly patients.
Depending on the severity, it may be classified as a medical emergency, as it can be a symptom of acute heart failure leading to the buildup of fluid in the lungs (pulmonary edema) as well as within and around the airways.
The distinction between bronchial asthma and cardiac asthma is especially important because some treatments for bronchial asthma, including inhalers, may worsen cardiac asthma or cause severe heart arrhythmias.
Bronchial asthma, in contrast, is caused by the inflammation and narrowing of pulmonary airways, causing characteristic breathing difficulties. Bronchial asthma has nothing to do with fluid in the lungs or heart disease or even the heart failure associated with cardiac asthma.