Can you provide a step‑by‑step interpretation of a 12‑lead ECG if I upload a clear image, given the patient’s age, gender, symptoms (chest pain or dyspnea), relevant history (heart disease, diabetes, hypertension) and current medications?

Yes, I Can Provide Step-by-Step 12-Lead ECG Interpretation

I can systematically interpret a 12-lead ECG if you upload a clear image and provide essential clinical context including age, gender, presenting symptoms (chest pain, dyspnea, syncope, palpitations), relevant cardiac history, and current medications. 1

Required Information for Accurate Interpretation

Before uploading your ECG, gather these critical details:

• Patient demographics: Age and gender (affects normal values for QTc and axis) 1
• Presenting symptoms: Chest pain character, dyspnea, syncope, palpitations, or fatigue 2, 3
• Cardiac history: Known coronary disease, cardiomyopathy, hypertension, diabetes 4, 3
• Current medications: Antiarrhythmics, beta-blockers, calcium channel blockers, diuretics, psychotropics, or QT-prolonging drugs 2
• Previous ECGs: Any prior tracings for comparison (new changes are far more significant than chronic findings) 1, 2

Systematic Interpretation Framework I Will Use

I will apply the following structured approach when you upload the image:

1. Technical Quality Assessment

• Verify electrode placement accuracy and identify artifacts that could lead to misinterpretation 1
• Check for baseline wander, electrical interference, or muscle tremor 1
• Confirm all 12 leads are clearly visible and properly labeled 1

2. Rate and Rhythm Analysis

• Calculate heart rate using the 300-divided-by-large-boxes method or 6-second strip method 1
• Identify underlying rhythm: sinus (P before each QRS with consistent PR interval) versus non-sinus 1
• Note any irregularities suggesting atrial fibrillation, premature beats, or pauses 1

3. Interval Measurements

• PR interval (normal 120-200 ms): Assess for AV blocks 1
• QRS duration (normal <120 ms): Identify bundle branch blocks or ventricular conduction delays 1
• QTc interval (normal <450 ms men, <460 ms women using Bazett's formula): Screen for long-QT syndrome risk 1

4. Axis Determination

• Examine leads I and aVF to determine electrical axis 1:
  • Normal axis: Both positive (+90° to -30°)
  • Left axis deviation: Lead I positive, aVF negative (-30° to -90°)
  • Right axis deviation: Lead I negative, aVF positive (+90° to +180°)

5. Chamber Enlargement

• Apply Sokolow-Lyon criteria for left ventricular hypertrophy: S in V1 + R in V5 or V6 >3.5 mV 1
• Assess for atrial enlargement patterns 1

6. Ischemia, Injury, and Infarction

• ST-segment deviations: Elevation >0.1 mV (limb) or >0.15-0.2 mV (precordial) suggests acute injury 1
• T-wave abnormalities: Inversion, hyperacute changes, or flattening 1
• Pathological Q waves: Duration >0.04 seconds or >25% of R wave amplitude indicates prior infarction 1
• Determine coronary territory based on lead distribution 1

7. Special Pattern Recognition

• Brugada pattern: Coved ST elevation in V1-V2 with downsloping morphology 4
• Early repolarization: J-point elevation with upward concavity (common in athletes) 4
• Pre-excitation (WPW): Short PR with delta wave 4
• Hypertrophic cardiomyopathy: Deep Q waves, giant T-wave inversions, extreme voltage 4

Critical Pitfalls I Will Avoid

• Never accept computer interpretation alone: Automated systems produce frequent errors requiring physician verification 4, 1
• Always interpret in clinical context: The same ECG pattern has different implications depending on symptoms 4, 1
• Compare with previous tracings: New changes are exponentially more significant than chronic findings 1, 2
• Consider age-specific variants: T-wave inversions in V1-V3 are normal in children; sinus bradycardia ≥30 bpm is normal in athletes 4, 1
• Verify lead placement: Misplaced precordial leads cause false diagnoses 1

When to Recommend Urgent Referral

Based on my interpretation, I will flag these high-risk scenarios requiring immediate action:

• ST-elevation patterns suggesting acute MI 2
• Syncope with any ECG abnormality 2
• New T-wave changes suggesting lateral ischemia 2
• QT prolongation with medications known to cause torsades 2
• Complete heart block or high-grade AV block 2
• Ventricular tachycardia or frequent PVCs with symptoms 2

Upload your ECG image now with the clinical context outlined above, and I will provide a detailed, systematic interpretation prioritizing patient safety and clinical decision-making.