PPM and LVPS ablation in dogs reduced VF inducibility from 100% to 21.9% (p<0.0001), and LVPW cut-and-sew operation in swine reduced it to 43.6% (p<0.0001), suggesting both Purkinje firing and reentry maintain VF.
Does targeted ablation or cut-and-sew operation reduce ventricular fibrillation inducibility in open-chest dogs and swine?
Both focal firing from the Purkinje network and reentry around the posterior papillary muscle contribute to the maintenance of ventricular fibrillation in large animal models.
Absolute Event Rate: 21.9% vs 100%
p-value: p=<0.0001
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. METHODS AND 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). CONCLUSION: 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 et al. (Tue,) conducted a other in Ventricular Fibrillation (n=28). Radiofrequency catheter ablation of PPM+LVPS (dogs) or LVPW cut-and-sew operation (swine) vs. Baseline (pre-intervention) was evaluated on Ventricular fibrillation inducibility in dogs after PPM+LVPS ablation (p=<0.0001). PPM and LVPS ablation in dogs reduced VF inducibility from 100% to 21.9% (p<0.0001), and LVPW cut-and-sew operation in swine reduced it to 43.6% (p<0.0001), suggesting both Purkinje firing and reentry maintain VF.
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