WHAT IS ELECTROCARDIOGRAPHY?
An electrocardiogram — abbreviated as EKG or ECG — is a test that
measures the electrical activity of the heartbeat. With each beat, an
electrical impulse (or “wave”) travels through the heart. This wave causes
the muscle to squeeze and pump blood from the heart. A normal
heartbeat on ECG will show the timing of the top and lower chambers.
The right and left atria, or upper chambers, make the first wave called a
“P wave" — following a flat line when the electrical impulse goes to the
bottom chambers. The right and left bottom chambers, or ventricles, make
the next wave called a “QRS complex." The final wave or “T wave”
represents electrical recovery or return to a resting state for the ventricles.
An ECG gives two major kinds of information. First, by measuring time
intervals on the ECG, a doctor can determine how long the electrical wave
takes to pass through the heart. Finding out how long a wave takes to
travel from one part of the heart to the next shows if the electrical
activity is normal or slow, fast or irregular. Second, by measuring the
amount of electrical activity passing through the heart muscle, a
cardiologist may be able to find out if parts of the heart are too large
or are overworked.