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2. A "Method" of ECG Interpretation

This "method" is recommended when reading all 12-lead ECG's. Like the physical examination, it is desirable to follow a standardized sequence of steps in order to avoid missing subtle abnormalities in the ECG tracing, some of which may have clinical importance. The 6 major sections in the "method" should be considered in the following order:

Topics for study:

  1. Measurements
  2. Rhythm Analysis
  3. Conduction Analysis
  4. Waveform Description
  5. Ecg Interpretation
  6. Comparison with Previous ECG (if any)


Measurements (usually made in frontal plane leads):

image 01-03

Go to: ECG Measurement Abnormalities (Lesson 4) for description of normal and abnormal measurements.

Rhythm Analysis

Go to: ECG Rhythm Abnormalities (Lesson 5) for description of arrhythmias.

Conduction Analysis

"Normal" conduction implies normal sino-atrial (SA), atrio-ventricular (AV), and intraventricular (IV) conduction.

image 01-05

The following conduction abnormalities are to be identified if present:

Go to: ECG Conduction Abnormalities (Lesson 6) for a description of conduction abnormalities.

Waveform Description

Carefully analyze the 12-lead ECG for abnormalities in each of the waveforms in the order in which they appear: P-waves, QRS complexes, ST segments, T waves, and... Don't forget the U waves.

ECG Interpretation

This is the conclusion of the above analyses. Interpret the ECG as "Normal", or "Abnormal." Occasionally the term "borderline" is used if unsure about the significance of certain findings. List all abnormalities. Examples of "abnormal" statements are:

image 08-01

Comparison with Previous ECG (if any)

If there is a previous ECG in the patient's file, the current ECG should be compared with it to see if any significant changes have occurred. These changes may have important implications for clinical management decisions.

Continue reading: "How To Determine Axis"

Test your knowledge on lessons 1 and 2!