Catheter Ablation of Premature Ventricular Contractions Arising from the Mitral Annulus after Mitral Valvoplasty TAKUMI YAMADA, M.D., PH.D., H. THOMAS McELDERRY, M.D., HARISH DOPPALAPUDI, M.D., ANDREW E. EPSTEIN, M.D., VANCE J. PLUMB, M.D., and G. NEAL KAY, M.D. From the Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama A 57-year-old man undergoing mitral valvoplasty underwent catheter ablation of symptomatic prema- ture ventricular contractions (PVCs) with a right bundle branch block and right inferior axis QRS mor- phology. Left ventriculography revealed a normal left ventricular function and visualized the anatomical relationships between the left ventricular outflow tract and the mitral annuloplasty ring. Electroanatomic mapping during the PVCs revealed a centrifugal activation pattern arising from the mitral annulus, and the PVCs were likely to be idiopathic. Successful radiofrequency ablation was achieved at the site close to the antero-paraseptal end of the mitral annuloplasty ring, which was located adjacent to the fibrous trigone. (PACE 2009; 32:825–827) premature ventricular contraction, mitral annulus, valvoplasty, radiofrequency catheter ablation Introduction This report describes catheter ablation of fo- cal ventricular arrhythmias (VAs) arising from the mitral annulus (MA) after mitral valvoplasty. This report may provide useful anatomical information for the catheter ablation of VAs in the left ventric- ular outflow tract (LVOT) and MA by illustrating a case presentation. Case Report A 57-year-old man undergoing mitral valvo- plasty was referred for catheter ablation of symptomatic premature ventricular contractions (PVCs). At baseline, monomorphic PVCs were fre- quent and exhibited a right bundle branch block and right inferior axis QRS morphology with an early transition (<V1) and an S wave in lead V 5 and V 6 (Fig. 1). For mapping, multipolar elec- trode catheters were positioned in the coronary sinus and His bundle region. The left ventricu- lography revealed a normal left ventricular func- tion and visualized the anatomical relationships between the LVOT and the mitral annuloplasty ring (Fig. 2). Electroanatomic mapping was per- formed using a 7.5-French, 3.5-mm tip irrigated ablation catheter (NAVI-STAR TM Thermocool TM ; Biosense Webster, Diamond Bar, CA, USA) via the femoral artery during the PVCs, as we re- ported previously. 1 The activation map revealed a centrifugal activation pattern arising from the Disclosure: There was no financial support for this study. Address for reprint: Takumi Yamada, M.D., Ph.D., Division of Cardiovascular Disease, University of Alabama at Birming- ham, VH B147, 1670 University Boulevard, 1530 3rd Avenue S, Birmingham, AL 35294-0019. Fax: 205-975-4720; e-mail: takumi-y@fb4.so-net.ne.jp Received June 2, 2008; revised July 14, 2008; accepted August 12, 2008. antero-paraseptal aspect of the MA where the ear- liest ventricular activation preceding the QRS on- set by 18 ms was recorded (Fig. 1). No prepoten- tials were recorded at that site. Pacing from that site exhibited a pace map with a perfect match to the PVCs. A single radiofrequency application with a target temperature of less than 40 ◦ C and power output titrated up to 40 W was delivered at that site close to the antero-paraseptal end of the mitral annuloplasty ring (Figs. 1 and 2), thus resulting in elimination of the PVCs. Thereafter, no VAs could be induced despite a programmed electrical stimulation as well as an isoproterenol infusion. During more than 1 year of follow-up, the patient has been free of any VA episodes with- out any antiarrhythmic drugs. No complications occurred. Discussion The MA has been demonstrated to be one of the major sources of idiopathic VAs originating from the left ventricle. 2,3 However, to the best of our knowledge, there have been no reports de- scribing focal VAs arising from the MA after valve surgery. In general, the mechanism of the VAs occurring after valve surgery may be scar-related reentry. 4 However, in this case, with a normal left ventricular function, the focal PVCs were likely to be idiopathic. Anatomically, the portion from the antero-septal to the septal aspect of the MA forms the fibrous trigone, which is the border between the LVOT and the MA. Because the mitral annu- loplasty ring had covered the myocardial portion, the deficient portion of the ring should indicate the site of the fibrous trigone. Therefore, in this case, the successful ablation site was located in the antero-paraseptal aspect of the MA. This may be an illustrative case providing useful anatomi- cal information for catheter ablation of VAs in the LVOT and MA. C 2009, The Authors. Journal compilation C 2009 Wiley Periodicals, Inc. PACE, Vol. 32 June 2009 825