ECG Level 1 Tutorial: Analyze the Waveforms
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Tutorial: Analyze the Waveforms
This module will teach the basic waveforms on ECG and a stepwise approach of how to analyze them. Practice each step and get feedback on your performance.
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Tutorial: Analyze the Waveforms Waveform Identification
Lessons
42
Times Practiced
1284
Cases Completed
1h 24m
Total Time spent
1m 24s
Average Time
Progress
Accuracy
Efficiency
Accuracy
Efficiency
1 Anatomy Anatomy
Current lesson 2 Waveform Identification Waveform Identification
3 Waveform Identification #2 Waveform Identification #2
4 Determine the heart rate Determine the heart rate
5 Do you have Rhythm? Do you have Rhythm?
6 P waves! Where are you? P waves! Where are you?
7 How many P waves? How many P waves?
8 P wave Size and Shape P wave Size and Shape
9 PR Interval PR Interval
10 P conducted to QRS? P conducted to QRS?
11 QRS Width QRS Width
Waveform Identification
This lesson will focus on defining the waveforms and intervals. The waveforms and intervals you need to learn at this stage include:
  • Waves:
    • P wave
    • QRS complex
    • T wave
  • Intervals:
    • PR interval
    • Width of QRS complex
    • ST segment
Later, we will introduce more details, such as QT interval, T wave changes, ST segment changes and many others (all of which are details not required for rhythm analysis).

Here is the P wave. It is atrial depolarization. It can sometimes be very difficult to see. Sometimes it is seen in some leads, but not others. A lesson very soon will give you practice with identifying the P waves.
P wave

The QRS complex is ventricular depolarization. A QRS complex does not require a Q wave plus an R wave plus an S wave. In the example below, there are all 3 waveforms (down-up-down = Q + R + S). Sometimes there is only 1 waveform in the QRS complex (and this is ok) and sometimes 2, and sometimes 3 and sometimes > 3. In all instances, we still call it the QRS complex.
QRS complex

The T wave is ventricular repolarization. It is typically much wider than the ventricular depolarization that generates the QRS. Sometimes it is upside down (inverted). Sometimes half of it is upside down and the other half upright; this is called biphasic. We will not analyze those components now (but we will later).
T wave

The PR interval is very very important. We will analyze it in more detail very soon. Please note: it starts at the START of the P wave and stops at the START of the QRS.
PR interval

The QRS duration is a measurement of how wide the QRS is. It starts at the start of the QRS and ends at the end of the QRS. Sometimes, the end of the QRS is ambiguous, so it can sometimes be difficult to know exactly where the end of the QRS is.


The ST segment gets a lot of attention because it can change with a myocardial infarction (heart attack). For rhythm analysis, it is not so important; however, because it is something trainees often think about, it is being included now.


Here is a reminder summary of the electrical events that occur during these waveforms and intervals:
All actions on the ECG

All the details on this image are electrical, with the exception of ventricular contraction, which of course, is a mechanical event. This detail is included to remind you that there is a good reason why there is a space between the QRS and the T wave.

Waveform identification is a skill. You will need to complete many practice cases to develop this skill. Each lesson in this module has many practice cases; make sure you can consistently score the required percent accuracy before moving on the next skill. If you are struggling with waveform identificaiton, please keep practicing because you will struggle with ECG Level 2 cases if your waveform identification skills are not strong.