In patients with severe mitral stenosis, which arrhythmia is most commonly developed due to atrial stretching?

• A. VT
• B. Sinus Rhythm
• C. Afib
• D. Aflutter

Answer: (C)

When the left atrium is chronically stretched by severe mitral stenosis, the atrial tissue undergoes structural and electrical remodeling. This dilation and fibrotic change creates a substrate where multiple small areas of slowed conduction and reentrant circuits can form, leading to chaotic atrial activity. That chaotic, disorganized atrial firing is the hallmark of atrial fibrillation, making it the most common rhythm disturbance in this setting. In atrial fibrillation, the atria quiver rather than contract effectively, producing an irregularly irregular pulse and loss of the atrial kick, which can worsen left-sided filling and symptoms, and it also markedly increases the risk of thromboembolism due to stagnant blood in the enlarged left atrium.

Atrial flutter, while possible, results from a more organized reentrant circuit and is less commonly seen in severe mitral stenosis than atrial fibrillation. Ventricular tachycardia is a ventricular arrhythmia not typically driven by atrial stretching. Sinus rhythm would indicate no arrhythmia, which is unlikely in the setting of significant atrial remodeling from mitral stenosis.