The major benefit of an ECG is that it can help determine which patients do not need an echocardiogram, a more accurate (but more expensive) diagnostic test.
Echocardiography
The best diagnostic test for heart failure is echocardiography. Echocardiography is a noninvasive, entirely safe test that uses ultrasound to image the heart as it is beating. Cardiac ultrasounds provide the following information:
- Accurate indications of valve function
- The amount of blood flow through the heart's chambers
- The location of the failure and where it has occurred
Doctors use information from the echocardiogram for calculating the ejection fraction (how much blood is pumped out during each heartbeat), which is important for determining the severity of heart failure.
Imaging Tests
Radionuclide Ventriculography. Radionuclide ventriculography is an imaging technique that uses a tiny amount of radioactive material (called a trace element). The substance is injected into a patient. As it passes through the bloodstream it is picked up on x-rays. This is a very important imaging technique for patients with heart failure. It is very sensitive in revealing heart enlargement or evidence of fluid accumulation around the heart and lungs. It is typically used in concert with angiography.
Magnetic Resonance Imaging. Magnetic resonance imaging (MRI) scans that use contrast dyes to improve resolution are proving helpful for identifying patients with irreversible heart damage. Damage appears as very bright areas on the scan.
Angiography
Doctors may recommend angiography if they suspect that blockage of the arteries is contributing to heart failure. This procedure is invasive.
- A thin tube called a catheter is inserted into one of the large arteries in the arm or leg.
- It is gently guided through the artery until it reaches the heart.
- The catheter measures internal blood pressure at various locations, giving the doctor a comprehensive picture of the extent and nature of the heart failure.
- Dye is then injected through the tube into the heart.
- X-rays called angiograms are taken as the dye moves through the heart and arteries.
- These images help locate problems in the heart's pumping action or blockage in the arteries.
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