AF

Atrial fibrillation

Atrial fibrillation (AFib) is the most common type of sustained cardiac arrhythmia, characterized by rapid and irregular electrical activity in the atria. Instead of coordinated contractions, the atria quiver or “fibrillate,” which disrupts the normal flow of blood into the ventricles.

1. Normal conduction: In a healthy heart, the sinoatrial (SA) node initiates an electrical impulse that travels through the atria to the atrioventricular (AV) node, causing a coordinated contraction of the atria, followed by the ventricles.
2. AFib conduction: In AFib, multiple ectopic foci in the atria generate erratic, disorganized impulses, causing the atria to quiver. The AV node receives an irregular influx of impulses, leading to an irregular ventricular response, typically rapid.

Clinical manifestations can range from asymptomatic to symptoms like palpitations, dizziness, fatigue, dyspnea, and in severe cases, syncope. The irregular, ineffective contraction of the atria increases the risk of thrombus formation, particularly in the left atrial appendage, which can lead to embolic strokes.