The Mechanism Of Branch Ventricular Tachycardia, The Long-term Effectiveness Of Catheter Ablation Therapy, And The Influencing Factors Of Recurrence

Part I Long-Term Clinical Outcomes of Catheter Ablation of Fascicular Ventricular Tachycardia and Risk Factor of RecurrenceBackgroundFascicular ventricular tachycardia(FVT)is a common form of idiopathic left ventricular tachycardia.There is rarer date concern the long-term outcomes of catheter ablation of FVT.This study aimed to investigate long-term clinical outcomes of patients undergoing ablation of FVT and identify predictors of arrhythmia recurrence in a large cohort.MethodsConsecutive patients undergoing FVT ablation at our catheter lab from March 2005 to December 2016 were enrolled.Activation mapping was performed to identify the earliest presystolic Purkinje potential during FVT that was targeted by radiofrequency ablation.Pace mapping was also used when detail activation mapping FVT was not available due to uninducibilty or unsustainable of FVT.Patients were followed up with clinic visits.ResultsA total of 234 consecutive patients(mean age,30±13 years;82%men)were enrolled.Detailed mapping during VT was available in 183(78.2%)patients,and acutely successful ablation was achieved in 231(98.7%)patients.With a mean follow-up of 58±42(1-135)months,VT recurred in 35(15.2%)patients,most of which had recurrence VT in the first year after ablation.No detailed mapping was the only significant predictor of FVT recurrence(OR:4.9,95%CI:2.3-10.7,P<0.001).ConclusionsAblation of FVT is associated with a success rate of 84.8%during a mean follow-up of 5years.Most of the recurrence VT occur in the first year after ablation.No detailed mapping is the only significant predictor of FVT recurrence.Part II Mechanism of Fascicular Ventricular Tachycardia and Reason of Recurrence after AblationBackgroundMechanism of fascicular ventricular tachycardia(FVT)has not been well established,although the majority of studies have laid more weight on there being a reentrant basis for FVT.EnSite Array(EA)visualizes beat-to-beat virtual activation of FVT.The aim of the present study was to characterize FVT reentrant reentrant circuit,using EA.We also analyzed the reason of FVT recurrence after ablation.MethodsThe 21 patients with left post FVT(mean age 33 ± 15 years,17 males)undergoing EA-guided primary radiofrequency ablation and 57 patients(mean age 28 ± 12 years,45 males)who had previous radiofrequency ablation for FVT in the other center were included.Mapping and ablation date were annualized.ResultsEA activation of FVT showed that FVT in the 21 patients,undergoing primary radiofrequency ablation,resulted from a microreentry mechanism.FVT foci were distributed in the mid-septal portion.The most common reason(in 91.2%patients)for FVT recurrence was that the target was not accurate in the previous procedure among 57 patients with recurrent FVT.The reason in remain patients(8.8%)was incorrect diagnosis.Conclusions FVT result from a microreentry mechanism,shown by EA virtual activation.Inaccurate target was the most common reason for FVT recurrence.Part III A special type of recurrent fascicle ventricular tachycardia after ablation:incidence,mechanisms and ablationBackgroundIt is not uncommon that changes in QRS morphology of tachycardia during or after the ablation procedure of left posterior fascicular(LPF)ventricular tachycardia(VT).The best ablation strategy of the newest VT has not been well established.We report the incidence of new onset VT in a large cohort,and describe the potential mechanisms and ablation strategy of that VT.MethodsWe analyzed idiopathic fascicular VT patients who underwent electrophysiological study and primary radiofrequency catheter ablation from March 2005 to December 2016 at our catheter lab.ResultsAmong 175 idiopathic fascicular VT patients who were referred for ablation,we identified 11(6.7%)patient(11 men,31 ± 10 years)presenting new onset right bundle branch block and right axis deviation VT,nine of which developed left posterior fascicular block during ablation of LPF-VT.Cycle length of the new onset VT was similar to that of the LPF-VT before primary ablation(403±48 ms vs.399±44 ms,P = 0.06).The earliest ventricular activation was recorded at the anterior septum,but the earliest Purkinje potential was recorded at mid-septal portion during the new onset VT and preceded the onset of the QRS complex of VT by 44±9 ms.Radiofrequency ablation at this site eliminated the new onset VT completely,without recurrence during a median follow-up of 72 months.ConclusionsThe LPF block may lead to exit site to the ventricular myocardium of LPF-VT through the left anterior fascicle where distant from the re-entrant circuit of the VT.The RF current should be target at mid-septal portion to eliminate the new onset VT.