Tricuspid Annular Remodeling in Tachycardia Induced Cardiomyopathy With Functional Tricuspid Regurgitation

This novel study examined tricuspid annular (TA) remodeling in conscious, awake sheep with functional tricuspid regurgitation (FTR) using tachycardia-induced cardiomyopathy. Fifteen sheep underwent thoracotomy with sonomicrometry crystal implantation around the TA and right ventricular epicardium. Eight surviving animals had baseline measurements acquired while awake, then underwent pacing (180-240 bpm for 18±2 days) until developing FTR. The model produced moderate-severe FTR, with a 48 percent increase in right ventricular (RV) volume, a 57 percent enlargement of the TA area, and a 24 percent perimeter expansion. Critically, all annular segments dilated significantly: the anterior perimeter increased by 27 percent, the posterior perimeter increased by 17 percent, and the septal perimeter by 25 percent (all p