Diagnosing heart failure
When you have heart failure symptoms, HonorHealth's cardiac specialists perform a set of clinical assessments, lab studies and diagnostic tests to confirm, or rule out, a diagnosis of heart failure.
Lab tests
Blood tests are one important method for determining a patient's diagnosis. In particular, a BNP (brain natriuretic peptide) test calculates the presence of a hormone secreted by the heart when it's injured or overworked.
Other helpful lab tests include blood cell count, a complete metabolic panel, urinalysis, a thyroid function test, a fasting lipid peptide and a test for medication levels.
Echocardiogram
An echocardiogram is one of the most useful diagnostic tests for heart failure. The key measurement used in an echocardiogram is ejection fraction (or EF). EF is calculated by comparing blood volume pumped from the heart's ventricles with the blood remaining in a ventricle at the end of a contraction. For example, a normal EF rate for the left ventricle is 55%. A reading of lower than 55% indicates heart weakness.
Additional diagnostic tests
Other diagnostic tests for heart failure include:
- Chest X-ray: This will evaluate the size of your heart, as well as basic heart structures, to determine the amount of fluid buildup in the lungs.
- EKG (Electrocardiography): Electrodes placed on the chest measure the electrical activity of the heart over time. Readings measure heart rhythm and possible weakness in the heart muscle.
- Cardiac stress test: Also called a treadmill test, it assesses heart function during physical exertion and calculates the volume of blood returning to the heart. You'll be asked to walk on a treadmill at different speeds and inclines. Heart rate, breathing and blood pressure are all measured. This test can be used in combination with an echocardiogram.
- Cardiac catheterization: The specialist places a thin plastic tube called a catheter into an artery or vein in the arm or leg and then guides it into the heart chambers or the coronary arteries. This diagnostic procedure can read blood pressure within the heart, blood oxygen levels and the heart muscle's overall blood-pumping capacity.
- Cardiac computed tomography (CT) scan: During a cardiac CT scan, an X-ray machine revolves around your body, taking images of each part of your heart. A computer then assembles these images into a 3-D picture of the entire heart. Scans indicate the presence of calcified plaque in the coronary arteries and illustrate the function of heart valves and pulmonary arteries.
- MRI: In magnetic resonance imaging, high-powered magnets and radio waves produce images of the heart.
- Radionuclide ventriculography: This measures the performance of the heart's ventricles. A special camera traces the flow of an injected radioactive material, called technetium, as it moves through the heart.
- Pulmonary function tests: These measure the lungs' ability to take in and release air, and analyze how well oxygen in the atmosphere is entering the body's circulatory system.
With the data obtained from the tests, your physician can determine the cause and classification of your heart failure and form an appropriate treatment plan.