Cardiac asthma: What causes it?

Cardiac asthma is not a form of asthma. It's a type of coughing or wheezing that occurs with left heart failure. Depending on how severe the symptoms are, this wheezing can be a medical emergency.

Heart failure can cause fluid to build up in the lungs, a condition called pulmonary edema. It also can cause fluid buildup in and around the airways. This can cause shortness of breath, coughing and wheezing similar to the symptoms of asthma.

True asthma is a long-term condition caused by inflammation of the airways. The inflammation narrows the airways, causing breathing trouble. True asthma has nothing to do with fluid in the lungs or heart disease.

The distinction is important because treatments for asthma and heart failure are different. Treatments for heart failure can help improve the symptoms of both heart failure and cardiac asthma. Overusing treatments for true asthma, such as rescue inhalers, could be harmful and potentially lead to a worsening of symptoms.