Preliminary Stydies On Catheter Ablation Of Refractory Ventricular Arrhythmia

Catheter ablation of ventricular tachycardia(VT)in patients with structural heart disease is currently indicated mostly as an adjunctive treatment when therapies from implantable cardioverter defibrillator occur,frequently in the setting of electrical storm.As for scar-mediated VT,epicardial reentrant circuits may exist.Thus,an epicardial access(EA)may be needed.Although catheter ablation has been proven as an effective treatment for prevention of arrhythmia recurrences in this population,the risk of major procedure-related complications is not negligible and the benefit of the procedure should be always weighed against potential risks.As for patients with contraindications for a retrograde transaortic approach,a transseptal approach as an alternative should be recommended.This study consists of two parts,one is to assess the outcomes of a novel pericardial puncture set with Tuohy needle for EA in canines;the other is to assess the feasibility and safety of a transseptal approach for left ventricular aneurysm(LVA)related ventricular tachycardia mapping and ablation.These modified technique and strategy could be considered for improve the outcomes.Part One:The use of a novel pericardial puncture set to facilitate epicardial access in caninesObjective:To assess the outcomes of a novel pericardial puncture set with Tuohy needle for epicardial access(EA)in canines.Methods:The pericardial puncture was performed in ten anesthetized dogs that were randomly divided to use the novel puncture set or the Tuohy needle.The procedures were conducted by three independent investigators who were in different levels in electrophysiology and with no experience of using the novel set.Each operator was given four attempts through the anterior and the posterior approaches on each animal via the subxiphoid access.All successful EAs were confirmed with the guidewire or contrast injections.Results:There was a significantly larger angle of needle insertion through the posterior approach compared with the anterior approach(68.0±7.26°vs.27.2±5.52°,P<0.01).There was no significant difference in the depth of needle insertion between the anterior and the posterior approach(69.3± 11.87mm vs.74.3±10.89mm,P=0.094).The Tuohy needle group had a relatively higher rate of complications compared with the novel puncture set group(inadvertent puncturing on the myocardium[10.0%versus 5.0%,P=0.491],injure to lung[1 vs.0],coagulated coronary vessel injure[0 vs.1]).Conclusions:In this canine study,we demonstrated that the novel pericardial puncture set has a low rate of complications,and can be used as an effective and safe tool in epicardial access.Part Two:Feasibility of the transseptal approach for mapping and ablation in patients with ventricular aneurysm related ventricular tachycardiaObjective:To assess the feasibility and safety of a transseptal approach for left ventricular aneurysm(LVA)related ventricular tachycardia mapping and ablation.Methods:Five patients with LVA related VT were selected for mapping and ablation.After a routine transaortic LV-mapping approach was failed,catheter ablation was performed via the transseptal approach with a steerable sheath in all these cases.Results:In these five patients,four had LV aneurysms located in the LV apical area,one in the septum.Acute ablation successes were all failed to achieve via the transaortic route.Two were due to aortic stenosis and tortuous peripheral arteries and the others due to failed to target the effective sites.All ablation procedures succeeded via the sequent transseptal approach with a steerable/non-steerable sheath,and no major complications related to the transseptal approach were reported.During the 12-month(6-16 months)follow-up,no electrical storm or episode of VT was documented.One VT recurrence occurred,yet acute success was obtained again through the transseptal approach.Conclusion:Transseptal approach is a feasible,safe and effective method of mapping/ablation in patients with LVA related VT and could be considered as an elective method to the transaortic route.