Atrial Fibrillation vs Ventricular Fibrillation on ECG: Key Differences

Understanding the differences between atrial fibrillation (AFib) and ventricular fibrillation (VFib) on an electrocardiogram (ECG) is essential for accurate diagnosis and timely treatment. Both are serious cardiac arrhythmias, but they affect different parts of the heart and present distinct characteristics on ECG readings.

Understanding Atrial Fibrillation (AFib)

1. Irregular QRS Complexes: One of the most notable features of AFib on an ECG is the presence of irregularly irregular QRS complexes. The baseline appears chaotic due to rapid, disorganized atrial activity.

2. Hemodynamic Stability: Patients with AFib are often hemodynamically stable, meaning their blood pressure and organ perfusion remain relatively normal. Most individuals remain conscious and alert, although they may experience palpitations, fatigue, or shortness of breath.

Understanding Ventricular Fibrillation (VFib)

1. Absence of Identifiable QRS Complexes: In VFib, the ECG tracing lacks clear QRS complexes. The baseline appears completely disorganized with chaotic, erratic waves, indicating uncoordinated ventricular contractions.

2. Hemodynamic Instability: VFib is a life-threatening condition that leads to immediate hemodynamic collapse. Patients typically lose consciousness rapidly, and if not treated promptly with defibrillation, it can result in sudden cardiac death.

Summary of Key Differences

While both AFib and VFib are types of arrhythmias, the key distinction lies in their origin and severity. AFib originates in the atria and is associated with a more stable clinical presentation, whereas VFib arises from the ventricles and is a medical emergency requiring immediate intervention.