title: Ventricular tachycardia originating from the septal papillary muscle of the right ventricle: electrocardiographic and electrophysiological characteristics.
abstract: BACKGROUND
  Premature ventricular complexes (PVCs) and ventricular tachycardia (VT) arising from papillary muscles of both ventricles have recently been described. There is a lack of data on VT originating from the right ventricular papillary (RV PAP) muscles. There have been no prior studies focused on the electrocardiogram (ECG) features and ablation of PVC/VT arising from the septal papillary muscle of the right ventricle.
  
  
  METHODS
  Among 155 consecutive patients with normal structural heart who underwent catheter ablation of PVC/VT, 8 patients with PVC/VT from the septal RV PAP muscle were identified. The site of origin of the arrhythmias was identified through activation/pace mapping and intracardiac echocardiography. All patients underwent radiofrequency ablation of the arrhythmia.
  
  
  RESULTS
  Data on 8 consecutive patients (2 men, age 42 ± 13 years old) were collected. All patients had a preserved ejection fraction (60 ± 4%). Septal RV PAP arrhythmias had a left superior axis and negative concordance or late R-wave transition in precordial leads. PVCs were spontaneous in 5 cases, were induced by isoprotenerol in 2 cases and by isoproterenol plus phenylephrine in another one. PVCs were never induced with calcium bolus and only rarely with burst pacing. Adenosine never terminated VT or suppressed the VT/PVCs. Radiofrequency, fluoroscopic, and procedural time were, respectively, 10.3 ± 3, 36.4 ±11.3, and 76.3 ± 27.5 minutes. During a mean follow-up of 8 ± 4 months, mean PVC burden was reduced from 14 ± 3% preablation to 0.1 ± 0.2% postablation.
  
  
  CONCLUSIONS
  PVCs and VT originating from septal RV papillary muscle could have a typical ECG pattern due to the site of the muscle involved. Radiofrequency ablation of this anatomic area is feasible and effective.
authors.affiliation: Department of Cardiology, University of Foggia, Foggia, Italy; Texas Cardiac Arrhythmia Institute - St. David's Medical Center, Austin, Texas, USA.
authors.forename: Francesco
authors.initials: F
authors.lastname: Santoro
authors.forename: Luigi
authors.initials: L
authors.lastname: DI Biase
authors.forename: Patrick
authors.initials: P
authors.lastname: Hranitzky
authors.forename: Javier E
authors.initials: JE
authors.lastname: Sanchez
authors.forename: Pasquale
authors.initials: P
authors.lastname: Santangeli
authors.forename: Alessandro Paoletti
authors.initials: AP
authors.lastname: Perini
authors.forename: John David
authors.initials: JD
authors.lastname: Burkhardt
authors.forename: Andrea
authors.initials: A
authors.lastname: Natale
mesh_terms: D000322:Adrenergic Agonists; D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation; D004452:Echocardiography; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005240:Feasibility Studies; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D010210:Papillary Muscles / Q000503:physiopathology* / Q000601:surgery; D011237:Predictive Value of Tests; D012074:Remission Induction; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D013997:Time Factors; D016896:Treatment Outcome; D016278:Ventricular Function, Right; D018879:Ventricular Premature Complexes / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology / Q000601:surgery
chemical_list: D000322:Adrenergic Agonists
keywords: papillary muscle; premature ventricular complexes; radiofrequency ablation; right ventricle; ventricular arrhythmia; ventricular tachycardia