How Diastolic Dysfunction Is Diagnosed

The primary method of diagnosing diastolic dysfunction, a type of heart failure in which the heart isn't able to relax fully after each beat, is with an echocardiogram (ECG) and, sometimes, other imaging tests. Leading up to such a test the condition may be suspected based on symptoms shared by other types of heart failure. Sometimes a blood test to detect elevated levels of a protein released by the heart in response to elevated pressure within the organ also is used to help diagnose heart failure with diastolic dysfunction.

Symptoms

There's no home test for diastolic dysfunction. In fact, the condition rarely cases discernible symptoms. However, because it tends to develop gradually, some people may begin to experience classic symptoms of heart failure as it progresses:

• Shortness of breath (dyspnea) or labored breathing during exercise that gets progressively worse
• Difficulty breathing while lying down or that disrupts sleep
• A chronic cough
• Excessive fatigue
• Unusual weight gain
• Edema (swelling) of the legs and ankles
• Fast or irregular heartbeat

B-Type Natriuretic Peptide (BNP) Blood Test

B-type natriuretic peptide is a molecule released into the blood by cells of the heart in response to elevated pressure within the organ. It causes the kidneys to excrete sodium and water, which serves to lower pressure within the heart to normal level. 

BNP can be detected in lab from a small sample of blood. However, there is a large gray zone between what is considered normal levels of BNP and what is not, and so this test cannot on its own be a reliable indicator of heart failure. Rather, a b-type natriuretic peptide blood test is used in conjunction with other tests to reinforce a diagnosis of diastolic dysfunction.

Imaging Tests

The most conclusive test for diagnosing diastolic dysfunction—as well as for assessing the severity of the condition and whether it is causing heart failure—are imaging tests.

Echocardiogram (Echo)

This specialized ultrasound can reveal how well the heart muscle and valves function while at the same time assessing diastolic relaxation and the degree of left ventricular "stiffness."

An echocardiogram can also sometimes reveal conditions that may be the cause of diastolic dysfunction:

• Ventricular hypertrophy, a thickened left ventricular muscle associated with hypertension and hypertrophic cardiomyopathy
• Aortic stenosis, a narrowing of the valve in the large blood vessel branching off the heart (aorta)
• Restrictive cardiomyopathy, when the walls of the lower chambers of the heart are too rigid to expand as they fill with blood

An echocardiogram also can measure left ventricular ejection fraction (LVEF). This is the amount of the blood the left ventricle of the heart is able to pump out with each beat.

A normal LVEF is greater than 50%, which means the left ventricle is able to pump out more than half of the blood that's inside it. In some people with diastolic heart failure, the systolic function of the heart (that is, its ability to eject blood with a strong pumping action) is normal. In other words, they have heart failure despite having a normal left ventricular ejection fraction.

Electrocardiogram (ECG, EKG)

An electrocardiogram evaluates the electrical system of the heart. For this test, ten electrodes (flat metal discs) are placed strategically on a person's chest, arm, and leg. The electrodes are attached to a machine that reads the electrical charges generated by each heart beat. This information is graphed as wave patterns that on a graph. An ECG is noninvasive and takes no more than 10 to 15 minutes from start to finish.

Cardiac magnetic resonance imaging (MRI, CMR)

Cardiac MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of the structures within and around the heart. It requires remaining completely still while lying inside an MRI scanner—a tube large enough to surround the entire body.

This test yields high contrast and high resolution images by mapping radio wave signals absorbed and emitted by hydrogen nuclei (protons) in a powerful magnetic field. A cardiac MRI can tell a doctor a lot about how much strain the heart is undergoing as well as detect deformation, left atrial size, and trans-mitral blood flow. Because it's costly, it is not widely used.

Nuclear imaging

Imaging tests such as the positron emission test (PET) and the single photon emission computerized tomography (SPECT) sometimes are used to identify diastolic dysfunction in people who do not yet exhibit symptoms. These tests involve the injection of radioactive dyes known as "radiotracers" that the heart will absorb or not, depending on how it's functioning. These color changes can help a doctor detect if certain muscles of the heart are not able to pump as they normally would.

Cardiac Stress Test

A cardiac stress test (also known as a cardiac exercise test) measures the heart's response to physical exertion in a controlled setting. It involves walking on a treadmill or pedaling a stationary bike for 30 to 60 minutes during which your blood oxygen level, heart rhythm, pulse, and blood pressure are simultaneously monitored.

There are several types of stress tests, any of which might be used to help diagnose diastolic dysfunction and heart failure:

• Electrocardiogram stress test: Electrode patches attached to the chest measure electrical signals triggered by the heart during exercise
• Echocardiogram stress tests (or echo or cardio ultrasound): Sound waves create a moving picture of how the chambers and valves of the heart function while under stress. It can reveal areas of poor blood flow, dead muscle tissue, and areas of the heart muscle wall that aren’t contracting well or may not be getting enough blood.
• Nuclear stress tests: Radioactive dye is injected into the bloodstream to highlight blood flow. Images created by the test show how much of dye has reached various parts of the heart during exercise and at rest.
• Multiple gated acquisition (MUGA) scan: Uses radionuclide ventriculography (RVG) or radionuclide angiography (RNA) to produce a computerized image of the beating heart and the pumping function of the left and right ventricles. It is particularly useful for reading the overall pumping ability of the heart.
• Chemical stress tests: A medication such as dobutamine, persantine, or adenosine, is injected into the bloodstream to stress the heart.

Cardiac Catheterization

Cardiac catheterization is an invasive procedure in which a long, thin, flexible tube is inserted into the arm or groin and guided to blood vessels in the heart. Typically dye also is injected into blood vessels so they can be observed on an an X-ray or with ultrasound.

Cardiac catheterization can reveal if there are problems with how the heart relaxes and if the ventricles are not relaxing and filling normally.

Spirometry

This test measures lung function, which frequently is impaired in people who have heart failure. It involves breathing into a tube attached to a device called a spirometer that can measure how forcefully a person is able to push air out of their lungs.

Chest X-ray

A chest X-ray can show if the heart is enlarged or if there are signs of congestion in the lungs.

A Word From Verywell

Although diastolic dysfunction is common, many people with this disease may never experience symptoms. Those who do may dismiss their symptoms as just normal aging. It's important to know what the symptoms are and take them seriously if you begin to experience them. Diagnosing this disease early may prevent you from suffering the serious consequences of heart failure.