Pacing-Induced Transient Severe Mitral Regurgitation during Transcatheter Aortic Valve Implantation.

• Rapid pacing in TAVI can cause transient severe MR via mitral apparatus dysfunction. • Reversible MR should be suspected when severity fluctuates after intraprocedural pacing. • Serial echocardiography discerns functional from structural MR, guiding management.