How do I convert ECG (Electrocardiogram) data into a cardiac clinician report?

Converting ECG Data into a Cardiac Clinician Report

A systematic, structured approach to ECG interpretation should be followed to generate a comprehensive cardiac clinician report, incorporating rate, rhythm, axis, intervals, waveform morphology, and clinical correlation—all verified by a qualified physician rather than relying solely on computerized interpretation. 1, 2

Essential Components of the ECG Report

1. Technical Quality Assessment

• Document electrode placement accuracy and signal quality, as improper placement (especially precordial leads) can significantly alter interpretation and lead to false diagnoses 2
• Note any artifacts, baseline wander, or technical limitations that may affect interpretation 1
• Verify adequate frequency response (150 Hz minimum for adults, 250 Hz for children) to preserve diagnostic accuracy 2

2. Rate and Rhythm Analysis

• Calculate heart rate using either the large square method (count squares between R waves) or the 6-second strip method (count QRS complexes × 10), with normal range 60-100 bpm 2
• Identify the underlying rhythm (sinus, atrial, junctional, or ventricular) based on P wave morphology and relationship to QRS complexes 2
• Assess R-R interval regularity to determine rhythm consistency 2

3. Interval Measurements

• PR interval: Measure and report (normal 120-200 ms or 3-5 small squares) to assess AV conduction 2
• QRS duration: Document (normal <120 ms or <3 small squares) to evaluate ventricular conduction 2
• QT/QTc interval: Calculate and correct for heart rate (normal QTc <450 ms for men, <460 ms for women) 1, 2

4. Axis Determination

• Quickly determine quadrant by examining leads I and aVF (normal axis: -30° to +90°) 2
• Report any axis deviation (left axis: positive in I, negative in aVF; right axis: negative in I, positive in aVF) 2

5. Waveform Morphology Analysis

P Waves

• Describe morphology (normal: upright in I, II, aVF; biphasic in V1) 2
• Assess duration (<120 ms) and amplitude (<2.5 mm) 2

QRS Complexes

• Analyze for pathologic Q waves (>1 mm wide and >1/3 height of R wave) suggesting myocardial infarction 2
• Evaluate R wave progression across precordial leads (V1 to V4, then decreasing toward V6) 2
• Document any conduction abnormalities or bundle branch blocks 1

ST Segments

• Provide qualitative description with consideration of patient age and gender 1
• Measure ST elevation/depression at the J point, using appropriate thresholds: men <40 years (≥0.25 mV in V2-V3), men ≥40 years (≥0.2 mV in V2-V3), women (≥0.15 mV in V2-V3), all other leads (≥0.1 mV) 1
• Note if ST depression is ≥0.1 mV 1
• Include one or more possible causes based on other ECG abnormalities and clinical information 1

T Waves

• Document morphology (normally upright in I, II, V3-V6; inverted in aVR; variable in III, aVL, aVF, V1, V2) 1, 2
• Describe T-wave abnormalities and identify associated ST-segment changes if present 1
• State whether changes are indeterminate or likely associated with a specific cause 1

U Waves

• Note presence (most evident in V2-V3, heart rate dependent, rarely present >95 bpm) 1
• Document any abnormal amplitude increases that may indicate drug effects or electrolyte abnormalities 1

6. Additional Diagnostic Features

• Assess for chamber enlargement using P wave abnormalities and QRS voltage criteria 2
• Identify any signs of hypertrophy, ischemia, or infarction 1
• Note conduction abnormalities (PR prolongation, QRS widening, AV blocks) 1, 2

7. Clinical Correlation and Interpretation

• Always correlate ECG findings with the clinical picture and other laboratory results, as isolated findings (e.g., T wave abnormalities) have low specificity for any single cause 1
• Compare with previous ECGs when available to identify new or evolving changes 1, 2
• Consider patient-specific factors: age, gender (affects QT intervals and ST thresholds), medications (antiarrhythmics, psychotropics can alter findings) 1, 2

8. Computer Interpretation Verification

All computer-generated interpretations must be verified and appropriately corrected by an experienced electrocardiographer, as automated systems frequently contain significant errors and lack reproducibility 1

Critical Pitfalls to Avoid

• Never equate a single finding with a specific diagnosis (e.g., abnormal T wave = ischemia) without clinical context, as specificity is low 1
• Avoid over-reliance on computerized interpretation without physician verification, as errors remain common 1, 2
• Do not interpret ECG findings in isolation—always integrate with patient symptoms, history, and other diagnostic data 1, 3
• Recognize that the same ECG pattern may occur in different pathophysiologic states, explaining frequent low specificity for determining disease etiology 2

Report Structure Format

The final report should be algorithmically organized:

1. Technical quality statement
2. Rate and rhythm
3. Intervals (PR, QRS, QT/QTc)
4. Axis
5. P wave analysis
6. QRS complex analysis
7. ST segment description with possible causes
8. T wave description with interpretation
9. Additional findings (U waves, chamber enlargement, conduction abnormalities)
10. Clinical correlation and diagnostic impression
11. Comparison with previous ECGs (if available)
12. Physician signature confirming verification 1