How to Understand a Basic EKG

If you have ever watched an electrocardiogram (EKG--or ECG) monitor or looked at an EKG strip, you might have wondered how some healthcare professionals understand what they are observing. Though the patterns may seem mysterious, with some information about the heart, its normal electrical activity (Sinus rhythm), and how this activity is often displayed in an EKG, upon careful observation you can get a general idea of what is taking place within a heart. (see Reference 1; the remaining facts in this article are based on that reference as well)

Things You'll Need

• EKG monitor or strip

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Instructions

• 1

  Know the parts of the heart. The human heart has four chambers, two at the top called atria and two at its bottom named ventricles. Throughout the heart, there are both electrical cells and muscle cells that contract upon electrical stimulus.

• 2

  Know some basics of normal electrical cardiac activity. In a healthy heart, electrical cells near the top of the right atrium called the Sinoatrial (SA) node initiate an electrical impulse, sending it to the left atrium and downward through the center of the heart in what is called the Atrioventricular (AV) junction. From there it branches out into the right and left ventricles through bundle branches that end with the Purkinje fibers. This electrical impulse triggers depolarization of the atria and then of the ventricles, causing a contraction of muscle cells in their respective areas.

• 3

  Locate the first wave. Under usual monitoring conditions, you will see that the EKG displays, from left to right, a small upward hump before the appearance of some angled lines.This small hump is called the P wave and indicates the atria have received an impulse to contract.

• 4

  Find the QRS complex. Just after the P wave you will see a short generally straight line in the middle. After this there will be angled lines, usually dipping downward first, then shooting upward, then back down, and finally reaching back up to the middle. These are three waves, named Q, R, and S, which together are referred to as the QRS complex. This shows that the ventricles have received an impulse to contract. There are times, though, that only one or two of these waves can be seen.

• 5

  Locate the last visible wave. Soon after the QRS complex you will see another upward hump, usually larger than the P wave. This is the T wave and indicates ventricular repolarization. Atrial repolarization has already occurred, but the wave is usually buried in the QRS complex.