Blood backs up, and excess fluid collects in the lungs and other tissues.
The heart is unable to pump enough blood out to the organs and muscles. Anything that weakens the heart can bring on heart failure, but the most common cause is coronary artery disease, causing a heart attack. It can also result from high blood pressure, heart muscle or heart valves that are damaged by infection or inflammation, congenital defects, or heart rhythm problems. Symptoms include shortness of breath, fatigue, and a nagging cough. The cardiologist may listen for fluid in the lungs, or tap the chest, to see if fluid's collecting there.