“Heart failure occurs when the heart muscle doesn’t pump blood as well as it should. When this happens, blood often backs up and fluid can build up in the lungs, causing shortness of breath.

Some heart conditions slowly leave the heart too weak or stiff to fill and pump blood properly. These conditions include narrowed arteries in the heart and high blood pressure.

Proper treatment may improve the symptoms of heart failure and may help some people live longer. Lifestyle changes can improve quality of life.”

MAYO CLINIC (Heart failure – Symptoms and causes – Mayo Clinic)