How should an ECG image be analyzed for an adult patient with potential cardiovascular concerns, considering their medical history and current symptoms?

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Last updated: January 21, 2026View editorial policy

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I Cannot Analyze an ECG Image That Has Not Been Provided

You have not uploaded an ECG image for analysis. To provide a systematic interpretation of an ECG, I need you to actually attach or upload the image file to this conversation. 1

What You Need to Do

  • Upload the ECG image using the attachment function in this chat interface
  • Provide relevant clinical context including:
    • Patient's current symptoms (syncope, chest pain, dyspnea, palpitations, fatigue) 1
    • Known cardiovascular disease or risk factors (hypertension, diabetes, prior MI, heart failure) 1
    • Current medications, especially cardioactive drugs 1
    • Reason for obtaining the ECG (baseline evaluation, symptom evaluation, preoperative assessment) 1, 2

Why Clinical Context Matters for ECG Interpretation

ECG interpretation must always be performed in conjunction with clinical assessment, as the same ECG findings can have vastly different implications depending on whether the patient is symptomatic or asymptomatic. 3, 4

  • Active symptoms with ST elevation typically indicate acute coronary occlusion requiring emergent reperfusion therapy 3, 4
  • Asymptomatic ST elevation may represent non-ischemic causes (early repolarization, pericarditis, ventricular aneurysm) 3
  • ST depression patterns require clinical correlation to distinguish subendocardial ischemia from left ventricular hypertrophy or other non-ischemic causes 3, 4

Standard Systematic Approach I Will Use Once You Upload the Image

When you provide the ECG, I will analyze it using this algorithmic framework:

Step 1: Technical Quality Assessment

  • Verify standard calibration (25 mm/sec paper speed, 10 mm/mV amplitude) 5
  • Check for artifacts (muscle tremor, electrode misplacement, poor frequency response) that could create false patterns 5
  • Ensure proper lead placement, as incorrect positioning significantly alters interpretation 5

Step 2: Rate and Rhythm Analysis

  • Calculate heart rate (normal 60-100 bpm) 6, 5
  • Assess rhythm regularity and identify P waves before each QRS 6
  • Evaluate for bradycardia (<60 bpm) or tachycardia (>100 bpm) requiring clinical correlation 6

Step 3: Interval Measurements

  • PR interval: 120-200 ms (3-5 small squares) to assess AV conduction 6, 5
  • QRS duration: <120 ms (<3 small squares); prolongation suggests bundle branch block 6, 5
  • QTc interval: <450 ms (men), <460 ms (women) when corrected for heart rate 6, 5

Step 4: Morphology Analysis

  • ST segments: Should be isoelectric; elevation >1 mm or depression >0.5 mm is abnormal 6
  • Q waves: Pathological if ≥0.04 seconds wide and ≥25% of R-wave amplitude, suggesting prior MI 5
  • T waves: Assess for hyperacute changes, inversions, or flattening 3, 7
  • QRS morphology: Evaluate for left ventricular hypertrophy, bundle branch blocks, or poor R-wave progression 5

Step 5: Clinical Correlation and Risk Stratification

  • Compare with prior ECGs if available to detect interval changes 5
  • Integrate findings with cardiac biomarkers and imaging when available 5
  • Determine need for emergent intervention versus outpatient follow-up 1, 4

Critical Pitfalls to Avoid

  • Do not rely solely on computerized interpretation without physician verification, as automated readings frequently contain errors 5
  • Do not interpret ECG findings in isolation from clinical symptoms, as this leads to misdiagnosis 5, 3
  • Do not miss acute coronary occlusion that presents without classic STEMI criteria—nearly one-third of acute occlusions are missed when relying only on traditional ST elevation thresholds 7
  • Recognize STEMI-equivalents: New LBBB, ST depression in V1-V4 (indicating posterior MI), and hyperacute T waves all require emergent reperfusion consideration 7, 4

Please upload the ECG image now, along with relevant clinical information, and I will provide a detailed systematic analysis.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Guidelines for Optimal ECG Performance

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

The role of the ECG in diagnosis, risk estimation, and catheterization laboratory activation in patients with acute coronary syndromes: a consensus document.

Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc, 2014

Research

ECG diagnosis and classification of acute coronary syndromes.

Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc, 2014

Guideline

ECG Calibration Standards for Accurate Myocardial Infarction Detection

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Guideline

ECG Interpretation Guidelines for Adults

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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