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.
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.
Pak
Hui-Nam
HN
Korea University Cardiovascular Center, Seoul, Republic of Korea.
Kim
Young-Hoon
YH
Lim
Hong Euy
HE
Chou
Chung-Chuan
CC
Miyauchi
Yasushi
Y
Fang
Yong Hu
YH
Sun
Kyung
K
Hwang
Chun
C
Chen
Peng-Sheng
PS
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*