Performing and Interpreting a 12-Lead ECG

Introduction

The 12-lead electrocardiogram (ECG) is a fundamental tool in diagnosing and monitoring cardiac conditions. By analyzing the electrical activity of the heart, physicians can detect common arrhythmias and their manifestations.

Understanding the 12-Lead ECG

The 12-lead ECG provides a comprehensive view of the heart's electrical activity from different angles. The leads include:

• Limb leads (I, II, III)
• Augmented leads (aVR, aVL, aVF)
• Precordial leads (V1-V6)

Common Arrhythmias and Their ECG Manifestations

1. Atrial Fibrillation (AF)

Characterized by irregular R-R intervals and absence of distinct P waves.

2. Atrial Flutter

Displays sawtooth-shaped flutter waves in leads II, III, and aVF.

3. Ventricular Tachycardia (VT)

Wide QRS complexes with a rate exceeding 100 bpm, often leading to hemodynamic instability.

4. Ventricular Fibrillation (VF)

Chaotic electrical activity without identifiable QRS complexes, requiring immediate defibrillation.

Interpreting ECG Findings

• Analyze heart rate and rhythm.
• Evaluate QRS morphology and P wave characteristics.
• Look for ST segment deviations, indicating ischemia or infarction.

Conclusion

Proficiency in ECG interpretation is crucial for timely identification and management of arrhythmias. Regular practice and familiarity with standard patterns enhance diagnostic accuracy.