Long-Term Efficacy of Mitral Valve Transcatheter Edge-to-Edge Repair (M-TEER) for Exercise-Induced Mitral Regurgitation in a Cardiac Resynchronization Therapy (CRT) Non-responder: A Three-Year Follow-Up.

Mitral valve transcatheter edge-to-edge repair (M-TEER), a minimally invasive procedure that uses a clip to join the mitral valve leaflets, has emerged as an established treatment for severe mitral regurgitation (MR) in drug-refractory heart failure (HF). This case report presents an 80-year-old cardiac resynchronization therapy (CRT) non-responder with a complex cardiac history who underwent successful M-TEER. Despite optimal therapy, including CRT, she experienced recurrent HF symptoms. While resting echocardiography showed mild MR, exercise stress echocardiography (ESE) revealed severe MR. The M-TEER procedure resulted in trivial residual MR and significant symptom improvement. The patient's New York Heart Association (NYHA) functional class improved from III to I, with sustained benefits for three years post procedure. This case highlights the importance of comprehensive MR assessment, including ESE, in complex scenarios. It also underscores the potential long-term benefits of M-TEER in carefully selected CRT non-responders, even with borderline right ventricular function, when supported by thorough multidisciplinary evaluation.