Graph Paper - Course # 318-3
- The value of time and voltage just discussed is very important to understand, but it must be combined with an understanding of the grid or graph paper the tracing is printing upon that you are analyzing.
- The grid is broken down in small boxes (1 X 1 millimeter) and heavier darkened lined boxes.
- There are five small boxes going from left to right and bottom to top of each large box (5 X 5 mm).
Each small box has a time value of 0.04 second.
If there are five small boxes going across each large box, then the value of time for each large box equals 0.20 second
(5 small boxes X 0.04 second = 0.20 second)
(5 LARGE BOXES X 0.20 SECOND = 1 SECOND)
- Voltage is important when measuring the height or depth of a waveform.
- The height or depth provides an indication of the amount of electrical activity occurring within the heart.
- Voltage can be affected by a number of different factors to include the amount of viable muscle mass in the heart.
- When analyzing cardiac tracings, the question always comes up “where do I measure from”?
To keep it as clear as possible, it is important to establish the isoelectric line or baseline.
There are times when this can prove to be impossible, but in most cases if you can see the PR segment, ST segment and TP segment, you should have a strong sense that this is where the isoelectric line is located.
However, all three segments are not always on the isoelectric line
Where two out of the three of them are located when analyzing horizontally, this is typically where the isoelectric line is located.
How to use this module.
This module is organized into a series of lessons. These lessons are listed on the right side of the content area. To navigate to a lesson, either
click on the lesson name or use the arrows at the bottom right. Each lesson contains several slides. These slides are lists with tabs
that appear above each slide. To navigate to a slide, either click on the tab or use the gray arrows that appear on the left and right sides of the slides.
Within the lesson are questions. These questions are used to reinforce key concepts, but they are not used for scoring or grading. After
completing this module, we encourage you to use our drills and quizzes to practice what you have learned. Finally, after completing most or all of
the modules, you might try our EKG Graded Quizzes to test your knowledge.
Our affiliated website, Practical Clinical Skills, provides additional drills and quizzes with certifcates of achievement. If you have an account, then your signin name and password will
work on that website as well. Click here for EKG contents and apps at Practical Clinical Skills.
318 Graph Paper - Course # 318-3