title: Transthoracic epicardial ablation of mitral isthmus for treatment of recurrent perimitral flutter.
abstract: BACKGROUND
  Perimitral flutter (PMF) is a common form of left atrial tachycardia after atrial fibrillation (AF) ablation. The mitral isthmus (MI) is the standard ablation target. However, in some cases bidirectional block cannot be achieved.
  
  
  OBJECTIVE
  The purpose of this study was to describe the first experience using a transthoracic epicardial (TTE) approach to treat recurrent PMF after prior unsuccessful ablation.
  
  
  METHODS
  This is a case series of four patients with recurrence of highly symptomatic drug-refractory PMF (all male, median age 55 years, 3/4 hypertensive, 2/4 persistent AF, median AF period 24 months). Three patients presented with PMF-related tachymyocardiopathy. TTE ablation of MI was performed after a median of two prior endocardial MI and coronary sinus ablation attempts, using an open-tip 3.5-mm irrigated catheter (40 W, 45ºC). Persistent bidirectional block was assessed by activation mapping and differential pacing and was achieved in all patients.
  
  
  RESULTS
  No PMF recurrence was observed after median follow-up of 18 months (range 15-22 months; two patients without antiarrhythmic drugs and two with previously ineffective amiodarone). Left ventricular function normalized in all three patients with tachycardiomyopathy. There were no complications related to TTE approach.
  
  
  CONCLUSIONS
  The present study is the first to report the feasibility of a TTE approach for highly symptomatic PMF refractory to endocardial and coronary sinus MI ablation.
authors.affiliation: Unitat de Fibril·lació Auricular (UFA), Cardiology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain. Electronic address: berruezo@clinic.ub.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Berruezo
authors.affiliation: Unitat de Fibril·lació Auricular (UFA), Cardiology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Felipe
authors.initials: F
authors.lastname: Bisbal
authors.affiliation: Unitat de Fibril·lació Auricular (UFA), Cardiology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Fernández-Armenta
authors.affiliation: Unitat de Fibril·lació Auricular (UFA), Cardiology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Naiara
authors.initials: N
authors.lastname: Calvo
authors.affiliation: Department of Cardiology, Hospital Universitario Quirón-Madrid, Madrid, Spain.
authors.forename: José Ángel
authors.initials: JÁ
authors.lastname: Cabrera
authors.affiliation: Department of Anatomy and Cell Biology, University of Extremadura, Badajoz, Spain.
authors.forename: Damián
authors.initials: D
authors.lastname: Sanchez-Quintana
authors.affiliation: Unitat de Fibril·lació Auricular (UFA), Cardiology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Andreu
authors.affiliation: Unitat de Fibril·lació Auricular (UFA), Cardiology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Teresa M
authors.initials: TM
authors.lastname: de Caralt
authors.affiliation: Unitat de Fibril·lació Auricular (UFA), Cardiology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Brugada
authors.affiliation: Unitat de Fibril·lació Auricular (UFA), Cardiology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Lluís
authors.initials: L
authors.lastname: Mont
mesh_terms: D000328:Adult; D001282:Atrial Flutter / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D017548:Echocardiography, Transesophageal; D022062:Electrophysiologic Techniques, Cardiac; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve; D010496:Pericardium / Q000601:surgery*; D012008:Recurrence; D013906:Thoracoscopy / Q000379:methods*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: AF; CS; Catheter ablation; IQR; LAT; LMWH; MI; Mitral isthmus line; PMF; PV; PVI; Perimitral flutter; RF; TTE; Transthoracic epicardial approach; atrial fibrillation; coronary sinus; interquartile range; left atrial tachycardia; low-molecular-weight heparin; mitral isthmus; perimitral flutter; pulmonary vein; pulmonary vein isolation; radiofrequency; transthoracic epicardial