LAUSR

Mitral isthmus block can be assessed with left atrial appendage pacing. Introduction Catheter ablation has become a cornerstone of atrial fibrillation (AF) management. Pulmonary vein isolation is the recommended procedure for paroxysmal AF. For persistent AF and atrial flutters linear lesions in the left atrium are also frequently required. The mitral line generally connects the posterior mitral annulus to the left inferior pulmonary vein. It is, however, challenging to obtain mitral isthmus (MI) block. The vein ofMarshall (VOM) runs along the posterior mitral annulus and is suspected to be implicated in the genesis and maintenance of AF and atrial tachycardias. Ethanol infusion within the VOM has been reported to help in obtaining acute MI block. We present a case where the mitral line was quickly successfully blocked owing to a mechanical bump within the VOM after several conventional endocardial and epicardial ablation attempts.