Small-vessel Disease in a Patient with Atrial Flutter: Unveiling a Potential Vascular Mechanism of Tachycardia-induced Cardiomyopathy.

A 65-year-old man presented with new-onset exertional dyspnea. The predominant abnormality was a marked concentric thickening of the arteriolar walls with strong smooth muscle actin positivity, consistent with small-vessel disease (SVD). This case illustrates a potential mechanism of tachycardia-induced cardiomyopathy (TIC), in which SVD may contribute to impaired myocardial perfusion and reversible left ventricular dysfunction under persistent tachycardia.