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

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.

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

“…These findings were reproducible in our previous study in which there was stable reentry anchored to the PPM with the coexistence of a dominant domain during VF in canines and swine in vivo, particularly after giving propranolol. 7 However, it is still unclear whether a high frequency domain around the PPM represents a true mother rotor or if it is an epi-phenomenon. The PPM is the major anchoring structure of VF reentrant wavelets and is the site harboring the prominent Purkinje potentials.…”

“…7 To evaluate the distribution of the Purkinje cells, we took digital pictures of the tissue slides at ×200 magnification and quantified the percent of the area of Purkinje cells according to the Cx40 staining or cell morphology by Image Pro software (MediaCybernetics Inc, Bethesda, MD, USA). The percent of the area of the Purkinje cells was compared at the subendocardial, mid-myocardial and subepicardial levels in the dogs and swine.…”

“…7 The multi-electrode array catheter was positioned in the left ventricular (LV) and the endocardial geometry was generated. To localize the area of the PPM, we marked its location on the 3D reconstructed endocardial anatomy of the non-contact map using echocardiography (Sonos 1500, Hewlett Packard Inc, Palo Alto, CA, USA) ( Fig 1A).…”

“…7 We also reported that radiofrequency catheter ablation (RFCA) around the papillary muscle reduces VF inducibility in dog and rabbit hearts. 7,8 However, it is unclear whether the high frequency domain around the PPM is a true mother rotor or an epiphenomenon, so we designed this study to elucidate whether the mechanism of VF maintenance is reentry or Circulation Journal Vol.72, July 2008 focal Purkinje firing. The aims of this study were to test the effect of the left ventricular posteroseptal (LVPS) ablation, including PPM ablation (Purkinje destruction), and the LVPW cut-and-sew operation (CSO; blocking reentry) on VF inducibility, and to compare the transmural distribution of Purkinje cells in the LVPS of dogs and swine.…”

“…We previously reported that the posterior papillary muscle (PPM) is the major anchoring structure of VF reentrant wavelets and the site harboring prominent Purkinje potentials and the dominant domain. 7 We also reported that radiofrequency catheter ablation (RFCA) around the papillary muscle reduces VF inducibility in dog and rabbit hearts. 7,8 However, it is unclear whether the high frequency domain around the PPM is a true mother rotor or an epiphenomenon, so we designed this study to elucidate whether the mechanism of VF maintenance is reentry or Circulation Journal Vol.72, July 2008 focal Purkinje firing.…”