The Clinical Electrophysiology Study Of Arrhythmogenic Right Ventricular Cardiomyopathy

PartⅠ:inducting ventricular tachycardia in patient with Arrhythmogenic right ventricular cardiomyopathyObjective:This study was aimed to compare the high-frequency stimulation to the conventional stimulation in patients with ARVC and VT, and evaluate ventricular tachycardia induction characters whether can be used to diagnose ARVC.Background:Ventricular tachycardia is a big puzzle for treatment in arrhythmia, especially for ARVC patients. Although we get great progress in idiopathic ventricular tachycardia about the mechanism and catheter ablation, however, the further stuy in catheter ablation for the structural ventricular tachycardia is limited, that is because the study about VT substrate, VT mechanism and ablation strategy are still in early stage, there are different argues about VT induction and ablation end point, so it is necessary to do further study how to improve the VT induction rate, which is the basis for VT mechanism study. This study was to evaluate the effect of the high-frequency stimulation and conventional stimulation in ARVC patients and the value of the VT rate, the VT morphology and the VT last time to diagnosis for ARVC.Methods Sixty two consecutive ARVC patients (46 males and 16 females) were enrolled in the study (ARVC group), the mean age was 39±13.7 years. They were assigned in a random fashion to two groups. The conventional stimulation (CS, up to 3 extrastimuli in 2 right ventricular sites, as well as incremental stimulation up to 240 bpm) was applied in group A (n=29), and the high-frequency stimulation (HS) was applied in group B (n=33). HS was started from 250 bpm with 1 to 1 capture for at least 4 seconds with a step of 10 bpm till the VT was induced or the 1 to 1 capture was lost. This procedure was repeated after the ablation of induced VT was completed in ARVC Isoproterenol was infused when it was needed.86 consecutive PSVT patients (51 males and 35 females) without structural disease were enrolled in control group (PSVT group). They were assigned in a random fashion to two groups to induce VT (group A and group B). And then compare the two stimulations in the PSVT group, the VT last time and the effect.Results The study indicated that the rate of VT induction was much higher in group A than group B. VT was easier to be induced in ARVC group than PSVT group. And the VT morphology, last time and rate had obviously difference (P<0.001) between ARVC and PSVT group, but there is no difference in PSVT group between these two different stimulations.Conclusion It is more effect for high-frequency stimulation than conventional stimulation in ARVC-VT patients. The VT morphology and last time and yield of ARVC-VT had obviously difference between the ARVC group and the PSVT group, so they can used to diagnose ARVC in early stage, and used for screening ARVC patients.PartⅡ:Dynamic substrate mapping ventricular tachycardias in arrhythmogenic right ventricular cardiomyopathyBackground:ventricular tachycardia (VT) is the major reason for sudden cardiac death in arrhythmogenic right ventricular cardiomyopathy (ARVC) patients. Most VTs originate from the abnormal substrate, so mapping the arrhythmogenic substrate can contribute to locate the target and choose the best ablation strategy. Non-contact endocardial activation mapping system (EnSite 3000) can perform dynamic substrate mapping for ARVC-VT, which is useful to find the critical isthmus, after that giving the best ablation strategy.Methods:Sixty two consecutive ARVC patients (46 males and 16 females) were enrolled in the study, the mean age is 39±13.7 years.20 patients had a history of syncope/presyncope,7 patients had an implantable ICD previously implanted. A multiple electrode array (MEA) catheter was positioned in the right ventricular (RV) through the left subclavian or femoral vein approach, after the geometry of RV was completed, pacing at right ventricular apex, right ventricular outflow tract, right ventricular free wall and right ventricular septum, and then performed DSM with these paced QRS and sinus rhthm QRS, VT induced after DSM.There were 3 kinds of mechanisms for ARVC-VT:focal, microreentrant, macroreentrant. Focal and microreent VT most located in low voltage area, macroreent most conduct through peritricuspid annulus and right ventricular outflow tract. Ablation strategy was determined by mapping result, such as ablation at origination, regional ablation abnormal substrate or linear ablation the peritricuspid annulus or right ventricular outflow tract.Results:One hundred and thirty eight VTs were induced in 62 ARVC patients, the mean VT rate was 226±32.2 bpm (130～310 bpm), there were 92 episodes of VT that had a heart rate≥200 bpm and 44 of 62 ARVC patients had≥2 morphologies of VT. Ablation the VT under the guidance of non-contact mapping with DSM, acute success was achieved in 89% (55/62) patients.While the rest patients achieved a modified success.Conclusions:under the guidance of non-contact mapping with DSM, the earliest activation of VT can be easily found, and it is clear to see the activation conduction, which help us to choose the best ablation strategy.Part III:Ablation ventricular tachycardia of arrhythmogenic right ventricular cardiomyopathyObjective:This study was aimed to estimate the safety and effective of ablation the ventricular tachycardia of arrhythmogenic right ventricular cardiomyopathy.Background:Intracardiac non-contact mapping provides a rapid and accurate isopotential mapping that facilitates catheter ablation of the ventricular tachyarrhythmias in arrhythmogenic right ventricular cardiomyopathy (ARVC).Methods:Thirty-two consecutive patients (26 men and 6 women, mean 37.2±13.8 years) were treated with ablation. Fourteen patients had a history of syncope/pre-syncope. Two patients had an implantable cardiac defibrillator (ICD) previously implanted.Results:There were 67 ventricular tachycardias (VTs) induced in the 32 patients. The average VT rate was 210±32.2 (130-310) bpm. There were 42 episodes of VT that had a heart rate≥200 bpm and 24 of the 32 patients (75%) had≥2 morphologies of VT. Regional ablation was applied by targeting the earliest VT activation sites under the guidance of non-contact mapping. Acute success was achieved in 84.4% (27/32) patients, and significant improvement was seen in 15, 6%(5/32) patients as evidenced by a slower rate of VT. None of the patients experienced syncope/pre-syncope or sudden death during the 28.6±16 (9-72) month follow-up。There were no complications of the procedure. At the end of follow-up, 81.3% of the patients were free of VT without medication while the rest of the patients achieved a modified success.Conclusions:The rapid ventricular tachyarrhythmias in ARVC patients can be abolished or improved significantly by regional RF catheter ablation under the guidance of non-contact mapping. There was no sudden cardiac arrest or death in those patients without ICD implantation. Delayed efficacy may occur in some patients after ablation.