Description of Heart Tests and Diagnostic Studies
Pulse Volume Recording (PVR)
Pulse Volume Recording (PVR) is a noninvasive vascular test that combines a blood pressure check with Doppler ultrasound to measure arterial blood flow in the arms and legs. Ankle brachial index (ABI) is a PVR test used to detect peripheral arterial disease (PAD).
The ABI measures blood pressure in your lower leg and compares it to the blood pressure in your arm. In the absence of disease, blood pressure in your ankle and arm should be about the same. But if your ankle pressure is half your arm pressure or lower, it could be a sign of PAD, a condition that causes poor circulation in your legs due to the narrowing of arteries.
Color Doppler Ultrasound
Color Doppler uses standard ultrasound methods to produce a picture of a blood vessel. In addition, a computer converts the Doppler sounds into colors that are overlaid on the image of the blood vessel and that represent the speed and direction of blood flow through the vessel.
Duplex Doppler Ultrasound
A duplex Doppler ultrasound uses standard ultrasound methods to produce a picture of a blood vessel and surrounding organs. In addition, a computer converts the Doppler sounds into a graph that provides information about the speed and direction of blood flow through the blood vessel being evaluated.
A Doppler ultrasound measures the flow of blood within the heart, veins, and arteries. It also evaluates valve movement to help detect blockages.
An arterial ultrasound can screen for stroke (carotid duplex), peripheral artery disease of the legs (lower extremity duplex), and aortic aneurysm (abdominal duplex), a common and potentially fatal disease.
A venous ultrasound is useful for identifying clots (deep vein thrombosis or DVT), varicose veins, and chronic venous insufficiency.
Holter Monitor and Event Loop Monitoring
A Holter monitor records the heart’s rhythm to help your heart doctor diagnose cardiac arrhythmia. The device is typically worn for 24 to 48 hours to record the heart’s rhythm when you have symptoms, like a continuous EKG (electrocardiogram).
An event monitor is similar to a Holter monitor except that it doesn’t continuously record your heart’s electrical activity. It only records during symptoms of arrhythmia. An event loop monitor, however, is always recording and erasing data. You activate it when you feel a symptom. A loop monitor may be external or implanted just under the skin on your chest.
Nuclear Stress Test
This test helps determine which parts of the heart are healthy and functioning normally and which are not. Before exercising, a very small and harmless amount of radioactive substance is injected into the patient. Then the doctor uses a special camera to identify the rays emitted from the substance within the body. This produces clear pictures of the heart tissue on a monitor. Using this technique, the heart has “hot” and “cold” spots that indicate the areas of heart muscle damage present before, during, and after exercise.
It is typically done for people with unexplained chest pain or to determine the location and amount of injured heart muscle after a heart attack.
Stress thallium scans often involve making two sets of images: one set is taken while the person is at rest (called resting images), and the other is taken after the heart has been stressed either through exercise (treadmill or bike) or by using a medication (both are called stress images). Then the resting images and the stress images are compared.
The medication used in place of exercise either causes healthy arteries (but not blocked ones) to become wider (dilate) or increases the workload on the heart, both of which increase the heart muscle’s need for oxygen and reveal areas of the heart that are not receiving adequate blood flow. Medication stress testing may be done instead of exercise stress testing for people with certain conditions that may make exercise difficult.
Stress Tests (Stress Echocardiogram)
Stress tests are tests performed by a doctor and/or trained technician to determine the amount of stress that your heart can manage before developing either an abnormal rhythm or evidence of ischemia (not enough blood flow to the heart muscle).
The most commonly performed stress test is the exercise stress test. The exercise stress test, also called a treadmill stress test, is a test used to provide information about how the heart responds to exertion. This is an echocardiogram that is performed while the person exercises on a treadmill. It involves walking on a treadmill at increasing levels of difficulty, while your heart rate and blood pressure are monitored.
This test can accurately visualize the motion of the heart’s walls and pumping action when the heart is stressed. It may reveal a lack of blood flow that isn’t always apparent on other heart tests. The echocardiogram is performed just prior and just after the exercise.
An echocardiogram (often called “echo”) is a graphic outline of the heart’s movement. During this test, high-frequency sound waves, called ultrasound, provide pictures of the heart’s valves and chambers. This allows the technician, called a sonographer, to evaluate the pumping action of the heart.
Transthoracic echocardiogram: This is the standard echocardiogram. Using a device called a transducer, high frequency sound waves (ultrasound) are bounced off the heart structures, producing images and sounds that can be used by the doctor to detect heart damage and disease. Echo is often combined with Doppler ultrasound and color Doppler to evaluate blood flow across the heart’s valves.
An electrocardiogram (also called EKG or ECG) is a test that records the electrical activity of your heart through 10 small electrode patches attached to the skin of your chest, arms, and legs. An EKG may be part of a complete physical exam or it may be used to further investigate symptoms related to heart problems.
Your doctor uses the EKG to:
- Assess your heart rhythm
- Diagnose poor blood flow to the heart muscle (ischemia)
- Diagnose a heart attack
- Evaluate certain abnormalities of your heart, such as an enlarged heart
Specific blood tests can be performed to see if there is a problem with your heart or blood vessels, including cholesterol profile to measure levels of HDL (good cholesterol), LDL (bad cholesterol) and triglycerides; cardiac enzyme tests; blood clotting tests and more.
A cardiovascular physical examination includes visually inspecting your physical appearance for symptoms, monitoring your heart rate, and checking your pulse and blood pressure.
In addition to checking your pulse and blood pressure and listening to your heart, your doctor can tell about your heart’s function by examining other parts of your body such as your eyes, arms, legs, and skin.
Heart Rate Monitoring, Pulse and Blood Pressure Check
Your doctor listens to your heart with the aid of a stethoscope. The opening and closing of your valves make a “lub dub” sound known as the heart sounds. The doctor can evaluate your heart and valve function and hear your heart’s rate and rhythm by listening to your heart sounds.
Your doctor will also feel your pulse and measure your blood pressure to check your heart’s rate, rhythm, and regularity. Each pulse matches up with a heartbeat that pumps blood into the arteries. The force of the pulse also helps evaluate the amount (strength) of blood flow to different areas of your body. Blood pressure is the force or pressure exerted in the arteries by the blood as it is pumped around the body by the heart.