Objective To investigate the electrocardiographic characteristics ofpremature ventricular contractions (PVCs) and ventricular tachycardia (VT) originating from the different parts of great cardiac vein (GCV) and to evaluate the efficacy and safety of radio frequency catheter ablation (RFCA).Methods Four patients with PVCs/VTs, including 2 cases of PVC, 1 sustained VT and 1 non- sustained VT, underwent electrophysiologic study using conventional mapping techniques and also received catheter ablation for the arrhythmias via GCV.Mapping and RF energy application at endocardial sites of left and right ventricular outflow tract (LVOT, RVOT) or mitral annulus did not eliminate the arrhythmias in all the patients.The arrhythmias were finally mapped and ablated from coronary venous system.Electrocardiographic characteristics were analyzed in cases with successful ablation via the distalpart (located proximal to the origin of anterior interventricular vein) or the most distal part (located distal to the origin of anterior interventricular vein) of GCV.Results Only 1 case succeeded in the first procedure of catheter ablation using the common temperature- controlled catheter, other 3 cases failed due to unable to delivered RF energy with high impedance within coronary sinus.The arrhythmias in 2 of 3 cases were successfully ablated using irrigated- tip catheter under the guide of Ensite3000 NavXin the second procedure, with the overall success rate of 75 ％ (3/4).The successful ablation site was located in the distalpart of GCV in 1 patient, the most distal part of GCV in 2 cases.The earliest epicardial activation was preceding the onset of the QRS complex by (36.00± 2.65) ms, and there were atrialand ventricular potentias in sinus rhythm at the successful ablation sites.Pacing reproduced QRS morphology that was similar to the clinical PVCs/VTs in all patients (2 patients with 11/12- lead and 2 patients with 12/12- lead concordance of major and minor deflections).The electrophysiological characteristics were different among the PVCs/VTs originating from the distal part and most distal part of GCV.The pseudo delta wave (PdW) was ≥ 75ms in the distal part of GCV, and ＜75ms in the most distal part of GCV.For PVCs/VT originating from the distal part of GCV, their QRS complex morphology was R in lead V1 and Rs in leads V4～V6.For PVCs/VT originating from the most distal part of GCV, their QRS complex morphology was Rs in lead V1 and R in leads V4～V6.Conclusion When the ECG features suggest PVCs/VTs originating from LVOT or anterior mitral annular, and the PVCs/VTs can not be eliminated by RF application from the endocardium, access via the GCV for mapping and ablation ofthe arrhythmias may be an effective and safe route.%目的 探讨心大静脉(GCV)不同部位室性期前收缩(PVCs)和室性心动过速(VT)的心电图特征及射频导管消融治疗的疗效与安全性.方法 4例经GCV标测和消融患者,其中持续及短阵性VT各1例,PVCs2例.经左、右心室流出道(LVOT、RVOT)及二尖瓣环心内膜标测与试消融无效各2例,最后均经GCV标测与消融,并对GCV远端(前室间静脉分支前-二尖瓣环前壁心外膜)及最远端(前室间静脉分支后-LVOT)消融成功者的心电图特征进行分析.结果 首次均采用普通温控导管仅1例消融成功,因阻抗太高无法放电失败3例,其中2例再次经三维标测系统EnSite3000-NavX指导下,采用盐水灌注导管标测与消融均成功,1例放弃再次消融,成功率75.00%.经GCV远端及最远端消融成功各1及2例.激动顺序标测有效靶点心内电图较体表心电图QRS波群起始点提早(36.00±2.65)ms,可见A波及V波(V＞A);起搏标测的QRS波群与自发PVCs/VT形态12及11导联相同各2例.GCV远端及最远端消融成功者体表12导联心电图特征不同:(1)前者假性"δ"波时间≥75ms而后者＜75ms;(2)前者V1呈R型无S波群而V4～V6有S波(呈Rs型),后者则相反.结论 部分体表心电图特征符合LVOT或二尖瓣环前壁起源的PVCs/VT,经上述部位标测与消融无效者,应考虑经GCV采用盐水灌注导管进行标测与消融,且安全有效.
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