Congestive Heart Failure

Diagnosis

Mayo Clinic heart disease doctors with special training in heart failure (heart failure cardiologists) work with other specialists to evaluate and treat people who have heart failure. The team has training in many areas, including noninvasive studies which use radioactive dyes to show heart structure and function (nuclear cardiology), heart rhythm disorders (electrophysiology), echocardiography, radiologic heart imaging and cardiac catheterization.

To diagnose heart failure, your heart failure cardiologist discusses your medical history and risk factors, performs a thorough physical examination and may also recommend other tests, including:

• Blood tests. Blood tests may indicate other diseases that affect your heart. A blood test for congestive heart failure checks for levels of a hormone called B-type natriuretic peptide (BNP). Your heart secretes BNP in high levels when overworked. A large amount of BNP in the blood may suggest congestive heart failure.
• Chest X-ray. An X-ray image shows the size and shape of your lungs and heart. In congestive heart failure, your heart may appear enlarged and fluid buildup may be visible in your lungs. An X-ray can also be used to diagnose other conditions.
• Coronary catheterization (angiogram). In this test the doctor inserts a thin, flexible tube (catheter) into a blood vessel in your groin or elbow and guides the catheter to your heart. The doctor injects a dye into the arteries in your heart, making the arteries visible under X-ray. This test identifies narrowed arteries to your heart (coronary artery disease), which can cause congestive heart failure. The test also helps to show the strength of your heart's main pumping chamber (left ventricle) and the health of your heart valves.
• Echocardiogram. An echocardiogram uses sound waves to produce a detailed video image of your heart's size, structure and function. These images can help doctors determine your heart's pumping capacity and distinguish between forms of heart failure. This test also measures the percentage of blood pumping out of the heart's main pumping chamber (ejection fraction).
• Electrocardiogram (ECG). In this test, your doctor places sensor patches with wires attached (electrodes) on your skin to measure the electrical impulses given off by your heart. This test can reveal heart rhythm disorders and damage to your heart from a heart attack.
• Magnetic resonance imaging (MRI). An MRI uses magnetic fields and radio waves to create detailed images of your heart.
• Myocardial biopsy. In this test, your doctor inserts a small flexible biopsy cord into a vein in your neck or groin, and small pieces of the heart muscle are taken. This test is performed to diagnose certain types of heart muscle diseases that cause heart failure.
• Right heart catheterization. In this test, your doctor inserts a thin, flexible tube (catheter) into a blood vessel (vein) in your neck or groin and guides the catheter to the heart to measure pressures within the heart chambers. This helps guide treatment in heart failure.
• Stress tests. In a stress test or exercise test, you exercise on a treadmill or stationary bicycle, or take a drug to simulate heart activity during exercise, while an electrocardiogram (ECG) monitors your heart. The exercise test helps your doctor judge your therapy's effectiveness and plan the timing of more advanced treatments. Different types of stress tests measure the heart's response to exercise in different ways and are used in different situations. Mayo Clinic is one of the few centers in the world that measures the relaxation response of the heart to exercise, a test used to diagnose diastolic heart failure.
• Radionuclide ventriculography or Multiple-gated Acquisition Scanning (MUGA). In this nuclear medicine test, the doctor injects a small amount of radioactive dye into your vein and special cameras show how much blood your heart can pump with each beat.

Results of these tests help doctors determine the cause of your symptoms and develop a treatment plan. Doctors classify heart failure based on a scale of I to IV. In Class I heart failure, the mildest form, you can perform everyday activities and not feel winded or fatigued. In Class IV, the most severe, you have shortness of breath even when you are at rest.

Read more about chest X-ray, coronary catheterization (angiogram), echocardiogram, electrocardiogram, MRI, cardiac catheterization and stress test at www.MayoClinic.com.