title: Role of the posterior papillary muscle and purkinje potentials in the mechanism of ventricular fibrillation in open chest dogs and Swine: effects of catheter ablation.
abstract: BACKGROUND
  Papillary muscle (PM) ablation may terminate ventricular fibrillation (VF) in rabbit hearts. Whether or not PM ablation prevents ventricular fibrillation (VF) induction in large animals is unknown.
  
  
  METHODS
  We performed noncontact endocardial mapping and/or high-density epicardial mapping during VF in 12 dogs and 16 swine and tested the effects of posterior PM (PPM) ablation on VF inducibility.
  
  
  RESULTS
  During VF in progressive global ischemia (3 swine and 2 dogs), the highest dominant frequency (DF) was near PPM. The majority of the reentrant wavefronts during a propranolol infusion (swine) were anchored to the PPM. Purkinje potentials onset were recorded on the PPM both during sinus rhythm and during VF. Radiofrequency (RF) ablation of the endocardium on the PPM with a linear extension of the ablation line from the PPM to the mitral valve annulus and then the left ventricular apex in 7 dogs reduced the VF inducibility from 100% at baseline to 22% after ablation (P < 0.0001). RF applications to the anterolateral wall of dogs (n = 3) did not prevent VF induction. The application of RF energy near the PPM frequently initiated VF in swine (n = 7), preventing subsequent testing of VF inducibility.
  
  
  CONCLUSIONS
  In dogs and swine, the highest DF and majority of reentrant wavefronts during VF with acute global ischemia or during a propranolol infusion were located on the PPM. RF ablation targeted at the PPM reduced the inducibility of VF in normal dogs. However, the same ablation provoked incessant VF in swine, preventing subsequent testing of VF inducibility.
authors.affiliation: Korea University Cardiovascular Center, Seoul, Republic of Korea.
authors.forename: Hui-Nam
authors.initials: HN
authors.lastname: Pak
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Kim
authors.forename: Hong Euy
authors.initials: HE
authors.lastname: Lim
authors.forename: Chung-Chuan
authors.initials: CC
authors.lastname: Chou
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyauchi
authors.forename: Yong Hu
authors.initials: YH
authors.lastname: Fang
authors.forename: Kyung
authors.initials: K
authors.lastname: Sun
authors.forename: Chun
authors.initials: C
authors.lastname: Hwang
authors.forename: Peng-Sheng
authors.initials: PS
authors.lastname: Chen
mesh_terms: D000818:Animals; D017115:Catheter Ablation; D004285:Dogs; D004594:Electrophysiology; D010210:Papillary Muscles / Q000502:physiology / Q000601:surgery*; D011690:Purkinje Fibers / Q000502:physiology / Q000601:surgery*; D013552:Swine; D014693:Ventricular Fibrillation / Q000209:etiology / Q000601:surgery*