Intraprocedural echocardiographic guidance in transcatheter mitral valve interventions: from procedure-specific workflows to integrated multimodal platforms.

Mitral regurgitation (MR) is the most common left-sided valvular heart disease worldwide and carries significant morbidity and mortality when untreated. The expanding use of transcatheter mitral valve interventions (TMVIs), including mitral transcatheter edge-to-edge repair (M-TEER) and transcatheter mitral valve replacement (TMVR), to anatomically complex, high-risk patient populations has substantially increased the demands on intraprocedural echocardiographic guidance. Yet current consensus documents provide modality-level guidance without explicitly formalizing the divergent imaging requirements inherent to these two mechanistically distinct interventions. This state-of-the-art review synthesizes evidence on intraprocedural echocardiographic guidance for TMVIs, integrating current data on 2D and 3D transesophageal echocardiography, real-time multiplanar reconstruction (MPR), echocardiography-fluoroscopy fusion imaging, 3D intracardiac echocardiography, and artificial intelligence (AI)-assisted decision-support tools. Two fundamentally distinct imaging paradigms are identified and formalized: a leaflet-level, temporally driven framework for M-TEER and an annular-level, spatially driven framework for TMVR. These paradigms reflect divergent anatomical targets and imaging priorities, with concrete implications for workflow design, operator-echocardiographer communication, and complication avoidance. Real-time MPR serves as the geometric backbone bridging 2D temporal precision with 3D spatial clarity. AI-assisted tools provide a computational guidance layer enhancing spatial consistency and procedural reproducibility while preserving, and not replacing, expert echocardiographic judgment. Effective intraprocedural echocardiographic guidance is objective-driven rather than modality-centric. The modalities described in this review function not as interchangeable alternatives but as complementary layers of a coherent, workflow-integrated architecture. The transition toward integrated, platform-based multimodal guidance defines the trajectory of next-generation TMVI echocardiography, requiring rigorous prospective validation, protocol standardization across device platforms, and training frameworks that reflect the multimodal nature of modern structural practice.