An electrical impulse stimulates the muscle fibers in the heart to contract. The impulse spreads through the heart in a very organized manner. The heart's normal electrical impulse has a characteristic pattern. The EKG machine displays the pattern of the electrical impulse.

Abnormal electrical patterns on the EKG can help identify heart disease.

The EKG can identify:

• Heart attack
• Enlargement of the heart
• Cardiac arrhythmias:
• Second degree heart block
• Third degree heart block
• Atrial fibrillation
• Ventricular arrhythmias