Overview of Heart Failure Tests & Diagnosis
If you have heart failure symptoms or your doctor suspects you may be developing heart failure, the first step is a detailed medical history and description of your symptoms, followed by a comprehensive physical exam.
Blood tests will be done to check your blood count, kidney and liver function, levels of sodium and potassium, blood sugar, and other measurements. A chest x-ray will be performed to check the size of your heart and look for fluid buildup in your lungs, as well as determine if there is some other obvious cause of your heart failure symptoms. An electrocardiogram ( ECG or EKG) will record the electric activity of your heart to reveal any heart rhythm problems or lack of blood flow to the heart ( ischemia).
Your doctor may order imaging tests to check the movement of your heart and see if it is contracting and pumping normally. The most important of these tests is an echocardiogram, or "echo" for short. This test allows doctors to examine the size and movement of your heart and measure your heart's pumping ability, called ejection fraction (EF). Your ejection fraction is the percentage of blood pumped—or "ejected"—out of a filled pumping chamber ( ventricle) during each heartbeat. It is usually measured on the left ventricle because the left ventricle is your heart's main pumping chamber, supplying blood to the rest of the body.
Other imaging tests—such as a nuclear ventriculogram or cardiac MRI—may also be done to take a more detailed look at the structure of your heart and how it is working. You may also undergo stress tests to check how your heart responds to an increased workload and determine if there is enough blood flow to the heart. Stress tests are usually exercise tests (the standard exercise ECG or other exercise imaging tests); if you cannot exercise, you may have a pharmacological stress test that uses medication to mimic the effects of exercise on your heart.
If a diagnosis of heart failure is confirmed, you doctor will then classify your heart failure symptoms. The most widely used scale is the New York Heart Association (NYHA) classification system. The results help doctors determine the best course of treatment for you and to evaluate prognosis.
Many of the tests used to diagnose heart failure will also be used to investigate the causes of your heart failure. Identifying the cause is important because it helps doctors determine the best treatment and prevent your heart failure from getting worse. Rarely, a heart biopsy may be done after standard tests have failed to identify a cause.