Atrial Fibrillation ECG Interpretation | ECG of Atrial Fibrillation

Atrial Fibrillation ECG Interpretation | ECG of Atrial Fibrillation. Atrial Fibrillation (AF) is the most common cause of cardiac arrhythmias. AF is a complex arrhythmia characterised by both abnormal automatic firing and the presence of multiple interacting re-entry circuits looping around the atria. Episodes of atrial fibrillation are usually initiated by rapid bursts of ectopic beats arising from conducting tissue in the pulmonary veins or from diseased atrial tissue. In a patient of AF some significant changes occurs in the ECG wave. This articles deals with how to interpret an ECG of Atrial Fibrillation.

The above figure shows two examples of atrial fibrillation. The QRS complexes are irregular and there are no P waves.

A) There is usually a fast ventricular rate, e.g. between 120 and 160/min, at the onset of atrial fibrillation.

B) In chronic AF, the ventricular rate may be much slower due to the effects of medication and AV nodal fatigue.

Atrial Fibrillation ECG Interpretation

Read the tracing and write down 3 positive findings?

1) P-wave absent

2) R-R interval is irregular

3) Heart rate is  70 (7X10)

What is the ECG diagnosis?

Atrial fibrillation

Mention the underlying causes of AF?

  • Mitral Stenosis (MS)
  • Ischemic Heart Diseases (IHD)
  • Thyrotoxicosis
  • Hypertension
  • Idiopathic (Lone AF)

What is rhythm of pulse of this patient?

Irregularly irregular

What is heart rate? what is its type on basis of heat rate?

Heart rate is 70. Slow atrial fibrillation (slow when HR<100 and FAST when HR> 100 per min)

Mention the most common complications of Atrial Fibrillation.

  • Thromboembolism
  • Heart failure/ acute pulmonary edema

More ECG Tracing of Atrial Fibrillation


Davidson’s Principles & Practice of Medicine

Dr. Shahidullah Shamol (FCPS in Medicine)

Assistant Professor, Department of Medicine

Mymensingh Medical College

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