title: Left septal atrial flutter: electrophysiology, anatomy, and results of ablation.
abstract: BACKGROUND
  We describe the clinical and electrophysiological characteristics of a novel macroreentrant form of left atrial flutter circuit.
  
  
  RESULTS
  A total of 11 patients were included in the study. The mean tachycardia cycle length was 278+/-41 ms. Nine of the 11 patients were treated with antiarrhythmic drugs at the time of the study for concomitant atrial fibrillation. With the use of entrainment pacing and either the CARTO Biosense mapping system (9 patients) or conventional mapping (2 patients), the flutter circuit was found to rotate around the left septum primum with a critical isthmus located between the pulmonary veins posteriorly and/or mitral annulus anteriorly and the septum primum. In 5 patients, radiofrequency ablation was performed from the septum primum to the right inferior pulmonary vein (group 1), and in 6 patients, a lesion was made from the septum primum to the mitral annulus (group 2). After a follow-up of 13+/-6 months, 2 patients in group 1 and all patients in group 2 remained in sinus rhythm without recurrence.
  
  
  CONCLUSIONS
  Slowing of electric conduction in the left atrial septum due to antiarrhythmic drugs and/or atrial myopathy seems to promote left septal atrial flutter. Radiofrequency ablation of this arrhythmia is usually effective and safe. A line of block between the septum primum and the mitral annulus proved to be effective for cure of tachycardia.
authors.affiliation: Section of Pacing and Electrophysiology, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio, USA.
authors.forename: Nassir F
authors.initials: NF
authors.lastname: Marrouche
authors.forename: Andrea
authors.initials: A
authors.lastname: Natale
authors.forename: Oussama M
authors.initials: OM
authors.lastname: Wazni
authors.forename: Jie
authors.initials: J
authors.lastname: Cheng
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Yang
authors.forename: Harvey
authors.initials: H
authors.lastname: Pollack
authors.forename: Atul
authors.initials: A
authors.lastname: Verma
authors.forename: Phillip
authors.initials: P
authors.lastname: Ursell
authors.forename: Melvin M
authors.initials: MM
authors.lastname: Scheinman
mesh_terms: D000368:Aged; D001282:Atrial Flutter / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D005260:Female; D005500:Follow-Up Studies; D006346:Heart Septum / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome