title: Mapping and ablation of epicardial idiopathic ventricular arrhythmias from within the coronary venous system.
abstract: BACKGROUND
  The prevalence of epicardial idiopathic ventricular arrhythmias that can be ablated from within the coronary venous system (CVS) has not been described.
  
  
  RESULTS
  In a consecutive group of 189 patients with idiopathic ventricular arrhythmias referred for ablation, the site of origin (SOO) of ventricular tachycardia and/or premature ventricular contractions was determined by activation mapping and pace mapping. Mapping was performed within the CVS if endocardial mapping did not reveal an SOO. Venography of the CVS and coronary angiography were performed before ablation in the CVS. In 27 of 189 patients (14%+/-5%; 95% confidence interval), the SOO of the ventricular arrhythmia was identified from within the coronary venous system, either in the great cardiac vein (n=26) or the middle cardiac vein (n=1). The mean activation time at the SOO was -29+/-8 ms. Twenty of 27 patients (74%) underwent successful ablation within the CVS. Epicardial ventricular arrhythmias displayed a broader R wave in V(1) compared with arrhythmias in the control group (85 ms [interquartile range, 40] versus 65 ms [interquartile range, 95]; P<0.01). Two patients had recurrent premature ventricular contractions within 2 weeks after ablation, and no recurrences occurred in the remaining patients during a median follow-up of 13 months (range, 25). In the 7 patients with unsuccessful ablation, failure was because the ablation catheter could not be advanced to the SOO within the great cardiac vein (n=4), inadequate power delivery at the SOO (n=1), proximity to the phrenic nerve (n=1), or proximity of the SOO to a major coronary artery (n=1). Transcutaneous epicardial ablation was effective in 1 of 2 patients in whom it was attempted.
  
  
  CONCLUSIONS
  Almost 15% of idiopathic ventricular arrhythmias have an epicardial origin. ECG characteristics help to differentiate epicardial arrhythmias from endocardial ventricular arrhythmias. The SOO of epicardial arrhythmias can be ablated from within the CVS in approximately 70% of patients.
authors.affiliation: University of Michigan Health System, Ann Arbor, MI 48109-5853, USA.
authors.forename: Timir S
authors.initials: TS
authors.lastname: Baman
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Ilg
authors.forename: Sanjaya K
authors.initials: SK
authors.lastname: Gupta
authors.forename: Eric
authors.initials: E
authors.lastname: Good
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
authors.forename: Krit
authors.initials: K
authors.lastname: Jongnarangsin
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Matthew
authors.initials: M
authors.lastname: Ebinger
authors.forename: Thomas
authors.initials: T
authors.lastname: Crawford
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
authors.forename: Frank
authors.initials: F
authors.lastname: Bogun
mesh_terms: D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation / Q000009:adverse effects; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000503:physiopathology / Q000601:surgery*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000503:physiopathology / Q000601:surgery*; D010690:Phlebography; D012008:Recurrence; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D014680:Veins / Q000601:surgery; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*