Cardiac asthma is not a form of asthma. It's a type of coughing or wheezing that's a symptom of heart failure. Depending on how severe your symptoms are, this wheezing can be a medical emergency.
As a result of heart failure, fluid can build up in the lungs (pulmonary edema) and in and around your airways. This causes signs and symptoms — such as shortness of breath, coughing and wheezing — that may mimic asthma. Asthma is a chronic condition caused by inflammation of the airways, which can narrow them, leading to breathing difficulties. 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, including medications, can help improve your symptoms for both the heart failure and the cardiac asthma. Overusing treatments for true asthma, such as rescue inhalers, may actually worsen cardiac asthma and could cause dangerous heart rhythms.