Testing Your Heart
Before any diagnosis of heart disease can be made, it's necessary to perform some important tests. Studying the results of these tests helps physicians to make a correct diagnosis—the first step toward treatment.
 A stress test is used to determine how the heart handles its workload. The two basic kinds of stress tests are:
- exercise stress test: The patient walks on a treadmill at gradually increasing speeds while the patient is hooked up to an EKG (ECG) machine which monitors the heart rate.
- pharmacologic stress test: Instead of using a treadmill, the patient is given an injection of a drug that causes the heart to act as it would during exercise. In this test an EKG technician also monitors the heartbeat.
(Pharmacologic stress tests are sometimes needed when the patient has joint pain and cannot walk on a treadmill, or if you have other conditions that would make it difficult for you to exercise. If walking is difficult for you, The Joint Reconstruction Center at Bridgeport Hospital may be able to provide relief.)
Imaging
Both the exercise and pharmacologic stress test can be used with imaging. The two types of imaging are echocardiogram, and tracing substances. These techniques help improve the accuracy of the stress test. Visual images can be taken in one of two ways:
- by echocardiogram
- by injecting tiny amounts of a tracing substance into the circulatory system and using a scanner to see if the arteries are carrying the tracing substance to all parts of the heart. If the substance does not show up in any area, this indicates that blood supply to that area of the heart is blocked.
The cardiologist examines the EKG strips and images to determine if there are areas to be further investigated. If so, the patient may require catheterization to determine how serious the blockages are. Blockages can be treated with medications, angioplasty, or Coronary Artery Bypass Grafts.
Electrocardiogram (EKG)
When someone is having chest pain, the first test performed is an electrocardiogram (EKG). A trained technician conducts this test, which can tell the cardiologist if the patient is having a heart attack. Wires (or leads) are attached to the chest, arms, and legs using pads with gel or tape.
The machine makes an electrocardiogram—a painless recording of the heart's electrical impulses during the heartbeat. It's used especially in diagnosing problems with the heart rate, rhythm, and function. The test results in an EKG strip—like this one of a normal EKG.
Normal EKG |
The reason EKG monitoring is generally started immediately is that heart rhythm problems are the leading cause of death during the first several hours following an acute heart attack. If the EKG is not normal—if it looks like one of these strips—the cardiologist can tell that the patient has had a heart attack and that part of the heart muscle is not working properly. Treatment is then begun to stop the heart attack and treat the patient.
 Echocardiogram
If the EKG results are inconclusive, an echocardiogram may provide more information. An echocardiogram is a painless computerized ultrasound image of the structures of the heart, taken by an echocardiograph technician. External ultrasound images take from 20 to 40 minutes. With the patient lying down, the cardiac echosonographer puts a transducer coated with a warm gel on the chest. The sound waves pass through the chest wall and "echo" off the heart, giving a clear, two-dimensional image of the organ on the computer screen.
An ultrasound machine can produce computerized color images that show the blood going into the heart, through the valves and out again. If the blood is not following its normal smooth path, there may be a problem with the structure of the heart.
Using these images, the technician can measure the thickness of the heart's walls and valves, pinpoint leaky valves, or even check for heart infections. For people who have suffered heart attacks, the procedure can help doctors determine what damage may have been done to the heart.
A transthoracic echocardiogram of the heart is taken internally, the cardiologist performs these procedures. A small transducer is placed down the patient's throat into the esophagus (under sedation). This transesophageal procedure enables the cardiologist to get closer images of the heart.
Blood Pressure Test
Blood pressure is a simple measurement that may be taken by a nurse, technician, clinical care provider, or other healthcare professional.
A blood pressure reading consists of two numbers: systolic pressure (the first, higher number, which indicates pressure when the heart contracts to push blood out to the body) and diastolic pressure (the second, lower number, which indicates pressure as the heart relaxes between beats, allowing blood to flow into the heart). Normal resting blood pressure is below 140/90 mmHg.
The nurse or technician wraps the blood pressure cuff around the patient's upper arm and closes the air valve on the inflating bulb. Then, placing the head of the stethoscope over the artery on the inside of the elbow, the technician inflates the cuff by squeezing the bulb steadily until no sounds are heard through the stethoscope (because the pressure of the cuff has temporarily stopped the blood from pulsing through the artery).
The technician opens the valve slightly, allowing the pressure to fall gradually. As soon as the technician hears the first pulse sound, he or she records the number on the dial or mercury tube. This is the systolic pressure (the highest amount of pressure in the arteries, measured as the heart contracts.)
As the air continues to be let out, the pulse sounds will disappear when the cuff is so loose that it can no longer record the pulse. The point at which the sound disappears is the diastolic pressure (the lowest amount of pressure in the arteries, measured as the heart rests).
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