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How heart disease is diagnosed

Heart disease is our number-one killer so it’s important that you and your doctor know as much about the condition of your heart as possible. Understanding your own personal heart health can help you decide how to live, eat and exercise. It can also help your doctor keep minor heart problems from becoming major by initiating treatment sooner rather than later. There are several non-invasive tests that doctors use to determine the condition of the heart.

Resting electrocardiogram

Also known as EKG, ECG and cardiogram, the resting electrocardiogram measures and records the electrical impulses that stimulate your heart to contract. These electrical impulses travel, in an orderly fashion, through the various parts of the heart. Without these impulses the heart wouldn’t contract or “beat.” Because the electrical activity of all human hearts follows certain predictable, normal patterns, it is easy to detect a pattern that looks different.

During this procedure, which is often performed in your doctor’s office, electrodes or “leads” are attached to the arms, legs and chest. These leads detect the electrical impulses as they move through the heart. A “gel” is placed beneath each lead to help the transfer of electric current from the skin. The leads are connected to a machine that converts the electrical impulses into sharp, zig-zag lines on a strip of paper.

By looking at this strip of paper, a doctor can see abnormalities in the rate and regularity of the heartbeat. The size and shape of these zig-zag patterns can tell whether the person is suffering from, or has already suffered, a heart attack or damage to the heart muscle.

A resting EKG can give doctors a good baseline with which to compare later EKGs. It can show rhythm disturbances, old damage to the heart and whether the person is having a heart attack at that moment. But it doesn’t provide much information about how the heart behaves under stress or exertion.

Stress electrocardiogram or stress test

The stress electrocardiogram records the heart’s electrical activity while physical stress is placed on it. Stress tests are recommended if there is a history of premature coronary heart disease in your family, if you have one or more additional risk factors for coronary artery disease, or if other diagnostic tests or symptoms indicate that one is needed.

A stress test may be given in a doctor’s office, but often a special exercise laboratory is needed. Electrodes or “leads” are hooked up to your arms, legs and chest, and a blood pressure cuff is placed on one arm. Instead of lying on a table, you step onto a treadmill and begin to walk. As you walk, the speed increases and the incline becomes more steep, so that the heart must work harder and harder. The electrical activity of your heart is observed on a screen and recorded, along with the blood pressure, every three minutes. The stress EKG can help your doctor determine whether you have blockages in your coronary arteries. It also can be used to advise a patient with heart disease how much physical activity can be tolerated with safety.

Although both resting and stress EKGs yield valuable information, false or incorrect readings occasionally occur. But although they have limitations, EKGs are a valuable diagnostic tool when used in conjunction with the patient’s symptoms, physical examination and other laboratory tests.


The echocardiogram gives information about the physical structure and condition of the heart by using sound waves to create a black and white, moving picture of the heart. For this procedure, which usually takes place in a laboratory or cardiologist’s office, the patient lies on his or her back while a microphone-shaped instrument called a transducer is placed on the chest. This transducer sends sound waves into the chest, where they bounce off the different parts of the heart muscle. These resulting sound wave echoes are then transmitted into an ultrasound machine and converted into a moving image that you see on a screen.

Echocardiograms allow doctors to determine the size of the heart chambers, the thickness and strength of the heart muscle, the quantity of blood pumped, whether fluid is present in the sac surrounding the heart and whether the heart valves are abnormal or leaking.

Diagnosis and detection

The three procedures described above all are completely painless and yield an enormous amount of information about the heart. If you have symptoms such as shortness of breath or occasional chest pain or pressure, ask your physician whether these tests might be useful.

The most important thing to remember about heart problems is that the sooner you detect and diagnose them, the easier they are to manage and treat. Rather than assume anything about the health of your heart, always ask your doctor.