Electrocardiogram (EKG)

An electrocardiogram (EKG) is one of the simplest and fastest procedures used to evaluate the heart. Electrodes (small, plastic patches) are placed at certain locations on the chest, arms, and legs. When the electrodes are connected to an EKG machine by lead wires, the electrical activity of the heart is measured, and then printed for the physician's interpretation. An EKG does not send electricity into the body.

An EKG is done to:

• find the cause of unexplained chest pain, such as a heart attack, inflammation of the sac surrounding the heart, or reduced blood flow to the heart muscle
• determine the cause of symptoms of heart disease, such as unexplained chest pain, shortness of breath, dizziness, fainting, or rapid, irregular heartbeats (palpitations)
• check the heart's electrical activity
• find out if the walls of the heart chambers are too thick
• check how well medicines are working and whether they are causing side effects that affect the heart
• check how well devices implanted in the heart are working to control a normal heartbeat, such as pacemakers or implantable cardioverter-defibrillators
• check the health of the heart when other diseases or conditions are present, such as high blood pressure, high cholesterol, cigarette smoking, diabetes or a family history of early heart disease

Holter Monitoring

A holter monitor is a portable device that continuously monitors your heart rhythm. The device is a small, portable recorder that is worn on a strap over your shoulder or at your waist. Sticky patches (electrodes) are placed on your chest and connected to the recorder by thin wires. The electrodes pick up the electrical activity of your heart and transmit the information to the monitor for the information to be stored.

Many times an arrhythmia (irregular heart beat) will not occur during the brief period of an actual EKG test. If a doctor suspects an irregular heartbeat, he or she will want to record your heart rhythm over a longer period of time. A holter monitor keeps a record of the heart rhythm, typically over a 24-48 hour period, while the patient keeps a diary recording their daily activities and any symptoms they may feel. Upon completion of the monitoring period, the doctor will compare your heart rhythm recording to your activity and symptom diary.

Holter monitoring is done to:

• identify irregular heart beats
• determine if the heart rate is beating too slow or fast
• identify if an individual's symptoms, such as light-headedness, fainting spell, chest pain or shortness of breath, is associated with an irregular heart beat
• monitor the effectiveness of how well medications or pacemakers are working

Event Monitoring

A physician may choose to order an event monitor if your symptoms, such as light-headedness, fainting spell, chest pain or shortness of breath, occur less often. Event recorders are worn over a period of 30 days to allow the monitor to record you heart rhythm when you are having symptoms, or an "event".

Like a holter monitor, an event monitor also uses a recording device to monitor your heart rhythm when you are having symptoms, or an "event". Unlike the holter monitor, it does not continuously monitor your heart over a 24-48 hour period. When you feel a symptom such as dizziness, palpitations, fainting spell, you activate the device to record the event. After recording the event, you telephone the monitoring station, where a record is made of your event. Or, if you cannot get to a phone, you can save the information in memory, which can later be sent to a monitoring station. Your event stays recorded on the event monitor until it is transmitted to a monitoring station.

Event monitoring is done to:

• determine whether symptoms such as dizziness, palpitations, fainting spells, or chest pain are caused by rhythm disturbances

Tilt Table Test

A tilt table test is a diagnostic test used to help a physician determine why a patient has been experiencing dizziness, lightheadedness or fainting spells (syncope). There are a number of different factors that may cause fainting spells, and the tilt table test is used to assess one in particular – a sudden drop in blood pressure (due to a widening of the blood vessels), often with a drop in heart rate as well. Fainting that results from this change in blood pressure and blood vessels is now called neurocardiogenic syncope, although many people still refer to the syndrome as vasovagal syncope.

The tilt table test is conducted on a special table. By securing the patient on his or her back to the tilt table, and then tilting the table upright (head up and feet down), the factors leading to neurocardiogenic syncope may be simulated. This test is designed to detect orthostatic hypotension, one of the most common causes of fainting.

Medications may also be given to the patient to try to re-create the abnormal reflex. The patient's heart rate and blood pressure are monitored carefully throughout the test. Results from the test are available immediately, and a specific course of treatment can be prescribed at that time. There are very few risks associated with this test and it provides valuable information to help physicians diagnose a number of heart-related conditions.

A Tilt Table Test is done to:

• Assess the causes of vasovagal or neurocardiogenic syncope (fainting). Vasovagal or neurocardiogenic syncope is when the heart rate slows and the blood pressure decreases because the blood vessels dilate (open) as a result of an abnormal reflex of the nervous system.

A stress test, sometimes called a treadmill test or exercise test, helps a doctor find out how well your heart reacts to the demands of physical activity. During the exercise stress test you will walk on a treadmill. As your body works harder during the test, it requires more oxygen, so the heart must pump more blood. Even if your heart works well at rest, it may not get enough blood supply when it has to work harder. The stress test can help detect heart problems that may not be apparent while you are at rest.

During the stress test an electrocardiogram (EKG) records the electrical activity of your heart. Your blood pressure and any symptoms that you may experience will be monitored during the test.

A Stress Test is done to:

• diagnose the case of unexplained chest pain
• determine the hearts exercise capacity
• detect reduced blood flow to the heart muscle, which may indicate heart disease
• evaluate how well your medications or cardiac procedure is working
• observe for abnormal heart rhythm disturbances that may occur during exercise

Exercise Cardiac Perfusion Imaging Stress Test

Cardiac perfusion imaging is a medical test that involves an injection of a small amount of radioactive substance (tracer) while walking on a treadmill, which circulates in the bloodstream to show if the heart is receiving adequate blood supply under stress and/or resting conditions.

The tracer gives off a small amount of radiation that is detected with a scanning camera. A computer processes the information and produces pictures that show how the tracer is distributed to the heart. If an area of the heart receives less blood than the rest of the heart (because of a narrowed or blocked artery), it will pick up less radioactivity. This will show up as a lighter image and is referred to as a defect.

The radioactive tracer is injected at rest and again at exercise. Pictures (images) are taken while you are at rest and again after you exercise. This allows the physician to compare how much blood is flowing to the heart at rest and with exercise.

Exercise Cardiac Perfusion Imaging Stress Test is done to:

• identify areas of the heart muscle that have an inadequate blood supply
• quantify the extent of the heart muscle with a limited blood flow
• provide information about the heart’s pumping function
• determine the amount of scarring from a heart attack
• evaluate the success of coronary (heart) bypass surgery or angioplasty

Pharmacological (Chemical) Cardiac Perfusion Imaging Stress Test

Usually cardiac perfusion imaging is completed after an exercise (stress) test. If you are not able to adequately exercise, you may receive a pharmacological "chemical" stress test. A "chemical" stress test involves an injection of a drug that mimics the effect of exercise on the heart.

Regadenoson Cardiac Perfusion Imaging Stress Test

The medication most often used for pharmacological stress testing is Regadenoson. Regadenoson is injected into the vein during the test, causing the coronary arteries to dilate (widen), which increases blood flow to the heart muscle. Arteries that are diseased cannot dilate as much as healthy arteries. Once the dilating medication has been given, a small amount of radioactive substance (tracer) is injected into a vein. The tracer collects in the areas of the heart muscle with good blood flow.

The tracer gives off a small amount of radiation that is detected with a scanning camera. A computer processes the information and produces pictures that show how the tracer is distributed to the heart. If an area of the heart receives less blood than the rest of the heart (because of a narrowed or blocked artery), it will pick up less radioactivity. This will show up as a lighter image and is referred to as a defect.

The radioactive tracer is injected at rest and again after the Regadenoson injection. Pictures (images) are taken while you are at rest and after the chemical stress test. The physician is able to identify areas of the heart muscle with reduced blood flow as well as areas that are scarred from a previous heart attack by comparing the stress and resting images.

Dobutamine Cardiac Perfusion Imaging Stress Test

Another medication, Dobutamine, is used for patients who cannot take Regadenoson because they have severe asthma or chronic lung disease. If Dobutamine is the medication of choice, it is injected into a vein during the test. Dobutamine makes the heart beat faster and harder, as if you were exercising. As a result, it increases the flow of the blood to the heart muscle. Once the Dobutamine has been given, a small amount of the radioactive substance (tracer) is injected into the vein. The tracer collects in the areas of the heart muscle with good blood flow.

The tracer gives off a small amount of radiation that is detected with a camera. A computer processes the information and produces pictures that show how the tracer is distributed to the heart. If an area of the heart receives less blood than the rest of the heart (because of a narrowed or blocked artery), it will pick up less radioactivity. This will show up as a lighter image and is referred to as a defect.

The radioactive tracer is injected at rest and again after the Dobutamine infusion. Pictures (images) are taken while you are at rest and after the chemical stress test. The physician is able to identify areas of the heart muscle with reduced blood flow as well as areas that are scarred from a previous heart attack by comparing the stress and resting images.

Pharmacological (Chemical) Cardiac Perfusion Imaging Stress Test is done to:

• identify areas of the heart muscle that have an inadequate blood supply
• quantify the extent of the heart muscle with a limited blood flow
• provide information about the heart’s pumping function
• determine the amount of scarring from a heart attack
• evaluate the success of coronary (heart) bypass surgery or angioplasty

Echocardiogram

Echocardiogram is a test that uses ultrasound (sound waves) to create a moving picture of the heart. This common test allows a doctor to see your heart in motion — ventricles squeezing and relaxing, and valves opening and closing in rhythm with your heartbeat. Your doctor can use these images to identify various abnormalities in the heart muscle and valves.

Various types of echocardiograms are available, including:

Transthoracic echocardiogram (Echo)

This is a standard, noninvasive echocardiogram. A technician (sonographer) spreads gel on your chest and then presses a device known as a transducer firmly against your skin, aiming an ultrasound beam through your chest to your heart. The transducer records the sound wave echoes as they reflect off internal structures. A computer converts the echoes into moving pictures on a monitor. When sound waves bounce off blood cells moving through your heart and blood vessels, they change pitch. These characteristic changes (Doppler signals) help the doctor measure the speed and direction of the blood flow in your heart.

Transthoracic echocardiogram is done to:

• assess the size of the heart chambers and the thickness of the walls
• determine the heart's pumping strength
• evaluate the heart's valve function
• detect other heart conditions (fluid around the heart, blood clots or tumors inside the heart, and abnormal holes between the heart chambers)
• detect congenital heart defects in babies

Transesophageal echocardiogram (TEE)

If it is difficult to get a clear picture of your heart with a standard echocardiogram, your doctor may recommend a transesophageal echocardiogram. In this procedure, a flexible tube containing a transducer is guided down your throat and into your esophagus (food pipe) after medication is given to put you in a light sleep. Because the esophagus lies just behind the heart, the TEE provides much clearer images of the heart than a standard echocardiogram.

The transducer records the sound wave echoes as they reflect off internal structures. A computer converts the echoes into moving pictures on a monitor. When sound waves bounce off blood cells moving through your heart and blood vessels, they change pitch. These characteristic changes (Doppler signals) help the doctor measure the speed and direction of the blood flow in your heart.

Transesophageal echocardiogram is done to:

• detect blood clots or masses inside the heart
• assess the severity of some valve defects
• examine prosthetic (artificial valves)
• evaluate holes between heart chambers
• detect infection of the heart valves
• diagnose a tear in the lining of the aorta (the body's main artery.
• obtain clearer images (pictures) that a standard echo provides

Stress echocardiogram

A stress echocardiogram (echo) can also be called an exercise stress echo. This test combines an echocardiogram with an exercise stress test. It allows the doctor to see how well the heart works when it is made to beat faster and harder with exercise.

For a stress echocardiogram, ultrasound images of your heart are taken before and immediately after walking on a treadmill. If you are not able to exercise, a medication can be injected into your bloodstream to make your heart work as hard as if you were exercising. Some heart problems, particularly those involving the coronary (heart) arteries that feed your heart muscle, occur only during exercise.

Stress echo is done to:

• measure the severity of coronary heart disease
• assess the results of coronary procedures
• diagnose certain types of heart muscle or heart valve disease