What is the interpretation of this electrocardiogram (ECG)?

ECG Interpretation: A Systematic Approach

I cannot interpret a specific ECG without seeing the actual electrocardiogram image. To properly interpret an ECG, a qualified physician must visually examine the tracing according to established guidelines 1.

Importance of Proper ECG Interpretation

• ECG remains one of the most widely employed procedures for evaluating cardiovascular function, providing a painless, reproducible, and relatively inexpensive method to assess cardiac electrical activity 1
• Computer interpretations of ECGs should never replace qualified physician interpretation, as errors in computer interpretation are still common 1
• The ECG is the only practical, noninvasive method of recording and analyzing cardiac rhythm abnormalities 1

Systematic Approach to ECG Interpretation

A qualified physician should follow these steps when interpreting an ECG:

1. Rate assessment: Normal heart rate is 60-100 beats per minute 2
2. Rhythm analysis: Determine if the rhythm is regular or irregular 1
3. PR interval measurement: Normal PR interval is 120-200 ms (3-5 small squares) 2
4. QRS duration evaluation: Normal QRS duration is <120 ms (<3 small squares) 2
5. QT interval calculation: Should be corrected for heart rate (QTc, normal <450 ms for men, <460 ms for women) 2
6. Axis determination: Assess the electrical axis of the heart 1
7. Hypertrophy assessment: Look for evidence of chamber enlargement using validated criteria 1
8. ST-T wave abnormality detection: Evaluate for ischemia, injury, or other repolarization abnormalities 1

Technical Considerations

• Minimum frequency response for adults should be 150 Hz to preserve diagnostic accuracy 2
• Inadequate high-frequency response leads to underestimation of signal amplitude and smoothing of important features 2
• Proper electrode placement is critical, as incorrect placement can significantly alter ECG interpretation 2

Clinical Context

• Always interpret ECGs in the context of the patient's clinical presentation 1, 2
• The same ECG pattern may be recorded in patients with different structural and pathophysiologic states 1
• Both cardiac and non-cardiac conditions can produce ECG changes that mimic acute myocardial infarction 3

Common Pitfalls to Avoid

• Over-reliance on computer interpretation without physician verification 1, 4
• Failure to compare with previous ECGs when available 1
• Interpreting ECGs in isolation without considering clinical context 2
• Misidentification of normal variants as pathological findings 5

Maintaining Competency

• Ongoing medical education through workshops or self-assessment programs is recommended to maintain ECG interpretation skills 2
• Physicians who rarely interpret ECGs should be particularly vigilant about maintaining their skills 1
• No consensus exists on the minimum number of ECGs needed to maintain competency, but periodic objective assessment of interpretation skills is recommended 1