Both Purkinje cells and left ventricular posteroseptal reentry contribute to the maintenance of ventricular fibrillation in open-chest dogs and swine: effects of catheter ablation and the ventricular cut-and-sew operation.
BACKGROUND
Radiofrequency catheter ablation (RFCA) targeting the left ventricular posteroseptum (LVPS) and posterior papillary muscle (PPM) terminates or prevents ventricular fibrillation (VF) in rabbit and dog hearts. However, whether the mechanism of VF maintenance is reentry or focal Purkinje firing is unclear.


RESULTS
In the present study the effects of RFCA (endocardial ablation of PPM+LVPS in 7 dogs and 7 swine), left ventricular anterolateral wall ablation (LVAL in 7 dogs), and the cut-and-sew operation (CSO: along the left ventricular posterior wall (LVPW) beside PPM in 7 swine) on VF inducibility were compared. (1) VF inducibility was decreased from 100+/-0% to 21.9+/-31.2% (p<0.0001) by PPM+LVPS endocardial ablation, but not by LVAL ablation in dogs. (2) LVPW CSO reduced VF inducibility (100+/-0% to 43.6+/-9.5%, p<0.0001) in swine. (3) In contrast to the canine Purkinje network, which is mostly localized to the subendocardium, the swine Purkinje network extends to the subepicardial layer with a higher density (p<0.001).


CONCLUSIONS
Both PPM+LVPS ablation (Purkinje destruction) in dogs and LVPW CSO (blocking reentry) in swine reduce VF inducibility, suggesting that in both species focal firing from the Purkinje network and reentry around the PPM contributes to the maintenance of VF.
Pak
Hui-Nam
HN
Korea University Cardiovascular Center, Seoul. yhkim@unitel.co.kr
Kim
Gwang Il
GI
Lim
Hong Euy
HE
Fang
Yong Hu
YH
Choi
Jong Il
JI
Kim
Jin Seok
JS
Hwang
Chun
C
Kim
Young-Hoon
YH
D000818:Animals; D017115:Catheter Ablation; D004195:Disease Models, Animal; D004285:Dogs; D004562:Electrocardiography; D004699:Endocardium / Q000166:cytology; D006346:Heart Septum / Q000166:cytology / Q000502:physiology / Q000601:surgery; D006352:Heart Ventricles / Q000166:cytology / Q000601:surgery; D009206:Myocardium / Q000166:cytology; D010210:Papillary Muscles / Q000166:cytology / Q000502:physiology / Q000601:surgery; D011690:Purkinje Fibers / Q000166:cytology / Q000502:physiology* / Q000601:surgery*; D013045:Species Specificity; D013552:Swine; D014693:Ventricular Fibrillation / Q000503:physiopathology* / Q000601:surgery*; D016276:Ventricular Function