title: Ventricular arrhythmias originating from papillary muscles in the right ventricle.
abstract: BACKGROUND
  Premature ventricular complexes (PVCs) and ventricular tachycardia (VT) with origin in the left ventricular papillary muscle have recently been described. There are no prior studies describing the characteristics of the ventricular arrhythmias (VAs) arising from the right ventricular papillary muscles (RV PAPs).
  
  
  METHODS
  Among 169 consecutive patients who underwent a catheter ablation of a VA, eight patients with RV PAPs were identified (seven men, mean PVC burden 17.0% +/- 20%). A control group consisted of 10 consecutive patients with arrhythmias originating from the right ventricle (10 women, mean PVC burden 13.9% +/- 12.8%). All patients underwent cardiac magnetic resonance imaging (MRI). Intracardiac echocardiography was used to identify the site of origin of the RV PAP arrhythmias. The site of origin of a total of 15 distinct PAP arrhythmias was mapped to the following papillary muscles: posterior (n = 3), anterior (n = 4), or septal (n = 8).
  
  
  RESULTS
  Postablation echocardiograms did not reveal new tricuspid regurgitation. During a mean follow-up of 8 +/- 9 months, there were no adverse outcomes. The PVC burden was reduced from 17% +/- 20% preablation to 0.6% +/- 0.8% postablation in the RV PAP group and from 13.9% +/- 12.8% to 0.3% +/- 0.4% in the control group. The QRS complex was broader in the RV PAP group compared with in the control group (163 +/- 21 ms vs. 141 +/- 22 ms; P = .02). RV PAP arrhythmias originating from the posterior or anterior RV PAPs more often had a superior axis with late R-wave transition (>V4) compared with septal RV RAP arrhythmias, which more often had an inferior axis with an earlier R-wave transition in the precordial leads (<or=V4; P <.05).
  
  
  CONCLUSIONS
  PVCs and VT may originate in the RV PAPs. Radiofrequency ablation is effective in eliminating these arrhythmias.
authors.affiliation: University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Crawford
authors.forename: Giesela
authors.initials: G
authors.lastname: Mueller
authors.forename: Eric
authors.initials: E
authors.lastname: Good
authors.forename: Krit
authors.initials: K
authors.lastname: Jongnarangsin
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Matthew
authors.initials: M
authors.lastname: Ebinger
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; D018780:Body Surface Potential Mapping; D002037:Bundle-Branch Block / Q000503:physiopathology; D016022:Case-Control Studies; D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D010210:Papillary Muscles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013318:Stroke Volume; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging / Q000209:etiology*; D013997:Time Factors; D014463:Ultrasonography; D016277:Ventricular Function, Left; D018879:Ventricular Premature Complexes / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology