A Prospective Study Of Mitral Isthmus Anatomy And Its Association With Incomplete Linear Block In Atrial Fibrillation Patient With Mechanical Mitral Valve Replacement

Part1: Anatomical Feature of Mitral Isthmus in AtrialFibrillation Patient with Mechanical Mitral Valve ReplacementObjective: This study was aimed to investigate the anatomical feature of mitralisthmus in patients with mechanical mitral valve replacements (MMVR) whounderwent atrial fibrillation (AF) ablation.Methods: Twenty-nine consecutive patients who developed symptomaticpersistent AF post MMVR and referred for ablation in our center wereenrolled. Twenty-nine patients with NMV who underwent ablation ofpersistent AF during the same period were matched. With pre-proceduralcardiac computed tomographic imaging, MI anatomical features of all theparticipants were analyzed.Results: Pouched MI was observed in19(65.5%) MMVR patients, comparedto6(20.7%) controls (P=0.001). The MI depth was correspondingly deeper inthe MMVR group than the controls (10.0±3.7mm vs6.0±3.8; P<0.001). Noother anatomical parameters measured reached statistical differences.Conclusions: Pouched MI accounts for the majority of AF patients withMMVR. Part2: Association of Mitral Isthmus Feature with IncompleteLinear Block in Atrial Fibrillation Patient with MechanicalMitral Valve ReplacementObjective: This study was aimed to investigate the impact of mitral isthmus(MI) anatomy on the likelihood of achieving MI linear block in patients withmechanical mitral valve replacements (MMVR) who underwent atrialfibrillation (AF) ablation.Methods: Twenty-nine consecutive patients who developed symptomaticpersistent AF post MMVR and referred for ablation in our center wereenrolled. Twenty-nine patients with NMV who underwent ablation ofpersistent AF during the same period were matched. With pre-proceduralcardiac computed tomographic imaging, association of MI anatomy with MIlinear ablation of each participant was analyzed.Results: Bidirectional linear block across MI was achieved in21(72.4%)MMVR patients and22(75.9%) in the controls (P=0.764). In the multivariableanalysis, Pouched MI was an independent predictor of incomplete MI block.Conclusions: Pouched MI accounts for the majority of AF patients withMMVR and may be associated with incomplete bidirectional linear block ofMI.