Successful Catheter Ablation of Mitral Isthmus Related Multiple and Unstable Ventricular Tachycardias after Myocardial Infarction

概要

論文の詳細を見る
Catheter ablation in patients with multiple and unstable postinfarction ventricular tachycardias (VTs) by placing lines of radiofrequency lesions with using 3D electroanatomical mapping is still challenging. We report a case of 69-years-old male with such VTs in which a linear lesion across the mitral isthmus successfully eliminated tachycardias. Four distinct unstable VTs were induced: three with a left bundle (LB) and one with a right bundle (RB) morphology. The analysis of the ventricular activation sequence along the posterior aspect of the mitral annulus (coronary sinus) revealed that the direction of wavefront propagation during the LB-VTs was opposite to that during the RB-VT. Electroanatonical mapping demonstrated a wide inferior infarct region. Then pace mapping was performed along the infarct border to assume the putative exit sites of the induced VTs. Each pacemaps performed along the septal and lateral aspects of the infarct border reproduced the QRS morphology of LB- and RB-VT, respectively. Based on these data, all four VTs were considered to be "mitral isthmus related". Placement of a linear lesion across the isthmus rendered all VTs noninducible. Mitral isthmus plays a role in the genesis of unstable VT. Even when treating patients with multiple and unstable postinfarction VTs, catheter ablation can be feasible if a critical isthmus is identified in the mitral isthmus.