Electrocardiographic characteristics of repetitive monomorphic right ventricular tachycardia originating near the His-bundle

INTRODUCTION: Most idiopathic nonreentrant ventricular tachycardia (VT) and ventricular premature contractions (VPCs) arise from the right or left ventricular outflow tract (OT). However, some right ventricular (RV) VT/VPCs originate near the His-bundle region. The aim of this study was to investigate ECG characteristics of VT/VPCs originating near the His-bundle in comparison with right ventricular outflow tract (RVOT)-VT/VPCs. METHODS AND RESULTS: Ninety RV-VT/VPC patients underwent catheter mapping and radiofrequency ablation. ECG variables were compared between VT/VPCs originating from the RVOT and near the His-bundle. Ten patients had foci near the His-bundle (HIS group), with the His-bundle local ventricular electrogram preceding the QRS onset by 15-35 msec (mean: 22 msec) and His-bundle pacing produced a nearly identical ECG to clinical VT/VPCs. The HIS group R wave amplitude in the inferior leads (lead III: 1.0 +/- 0.6 mV) was significantly lower than that of the RVOT group (1.7 +/- 0.4 mV, P < 0.05). An R wave in aVL was present in 6 of 10 HIS group patients, while almost all RVOT group patients had a QS pattern in aVL. Lead I in HIS group exhibited significantly taller R wave amplitudes than RVOT group. HIS group QRS duration in the inferior leads was shorter than that of the RVOT group. Eight of 10 HIS group patients exhibited a QS pattern in lead V1 compared to 14 of 81 RVOT group patients. HIS group had larger R wave amplitudes in leads V5 and V6 than RVOT group. CONCLUSION: VT/VPCs originating near the His-bundle have distinctive ECG characteristics. Knowledge of the characteristic QRS morphology may facilitate catheter mapping and successful ablation.     

环形标测电极指导下射频导管消融右心室流出道室性心动过速

探讨环形电极对右室流出道室性心动过速(RVOTVT)的标测指导作用及射频消融方法。6例特发性RVOTVT患者,男4例、女2例,年龄35.0±6.3(18～42)岁。行常规电生理检查,应用环形电极标测右室流出道,以最早激动点结合窦性心律下起搏标测确定靶点。结果:4例起源于右室流出道间隔前部,1例起源于间隔后部,1例起源于游离壁,6例均成功进行了射频消融,成功率100%。平均手术时间78±22min。结论:环形标测电极可以指导快速寻找室性心动过速起源点,缩短标测及消融时间。     

起源于主动脉窦内反复单形室性心动过速和/或频发室性早搏的心电图特征及射频消融治疗

探讨起源于主动脉窦内的反复单形室性心动过速(简称室速)和/或频发室性早搏(简称室早)的心电图特点和射频消融治疗。分析35例该类患者的室速和频发室早的心电图、心内电生理检查和射频消融治疗情况。结果:室性心律失常起源于左冠状动脉窦(简称左冠窦)的30例、无冠状动脉窦3例和主动脉根部左冠窦下2例。左冠窦的心电图特点:Ⅰ和aVL导联为rs、rS或QS波形,Ⅱ、Ⅲ和aVF导联为R波形,胸导联R波移行区在V2或V3导联,V5、V6导联为高振幅R波,无S波;V2导联R高度/S高度比值1.29±0.36。主动脉根部左冠窦下起源的心电图特点:和左冠窦起源室性心律失常的心电图特点基本相同,但V5、V6导联有S波。无冠状动脉窦起源的心电图特点:Ⅰ和aVL导联为Rs或R波形,Ⅱ、Ⅲ和aVF导联为R波形,胸导联R波移行区在V3导联。34例消融成功,手术操作时间65~120min,X光曝露时间12~30min。1例出现冠状动脉前降支急性闭塞。随访2~53个月,无复发病例。结论:起源于主动脉窦内的室速和/或频发室早有其独特的心电图表现,射频消融能安全、有效地根治此类心律失常。     

Left Ventricular Outflow Tract Tachycardia Including Ventricular Tachycardia from the Aortic Cusps and Epicardial Ventricular Tachycardia

Idiopathic outflow tract ventricular tachycardia (VT) can arise from the right (RVOT) or left ventricular outflow tract (LVOT). The electrocardiographic (ECG) pattern of RVOT VT is typical in most patients, showing a monomorphic left bundle branch block (LBBB) QRS morphology with an inferior axis. Radiofrequency catheter ablation can be performed with a high success rate and provides a curative therapeutic approach. However, not all VTs with LBBB and inferior axis can be ablated from the RVOT. It has become apparent that LVOT VTs including VT originating from the aortic sinus of Valsalva or epicardium represent underrecognized VT entities which are also amenable to successful catheter ablation. Twelve-lead ECG criteria can contribute to distinguish between sites of VT origin.LVOT arrhythmias represent an increasingly recognized VT entity which can be safely and successfully treated by catheter ablation. Identification of VT origin using ECG criteria and differentiation of LVOT versus RVOT origin is essential in the careful planning of the ablation strategy.     

Ventricular tachycardias mimicking those arising from the right ventricular outflow tract

INTRODUCTION: Ablation of ventricular tachycardia (VT) arising from the right ventricular outflow tract (RVOT) has proven highly successful, yet VTs with similar ECG features may originate outside the RVOT. METHODS AND RESULTS: We reviewed the clinical, echocardiographic, and ECG findings of 29 consecutive patients referred for ablation of monomorphic VT having a left bundle branch block pattern in lead V1 and tall monophasic R waves inferiorly. Nineteen patients (group A) had VTs ablated from the RVOT, and 10 patients (group B) had VTs that could not be ablated from the RVOT. The QRS morphology during VT or frequent ventricular premature complexes was the only variable that distinguished the two groups. During the target arrhythmia, ECGs of group B patients displayed earlier precordial transition zones (median V3 vs V5; P < 0.001), more rightward axes (90 +/- 4 vs 83 +/- 5; P = 0.002), taller R waves inferiorly (aVF: 1.9 +/- 1.0 vs 2.4 +/- 0.5; P = 0.020) and small R waves in lead V1 (10/10 vs 9/19; P = 0.011). Radiofrequency catheter ablation from the RVOT failed to eliminate VT in any group B patient, but ablation from the left ventricular outflow tract (LVOT) eliminated VT in 2 of 6 patients in whom left ventricular ablation was attempted. CONCLUSION: The absence of an R wave in lead V1 and a late precordial transition zone suggest an RVOT origin of VT, whereas an early precordial transition zone characterizes VTs that mimic an RVOT origin. The latter VTs occasionally can be ablated from the LVOT. Recognition of these ECG features may help the physician advise patients and direct one's approach to ablation.     

Substrate in the interventricular septum for left ventricular and right ventricular outflow tract tachycardia: ablation from the right side of the septum

Simultaneous epicardial and endocardial mapping demonstrated that in a substantial number of ventricular tachycardias (VTs) endocardial, intramural, and epicardial structures are involved in the substrate of the reentrant circuits. Both right and left ventricular breakthrough has also been described during VT originating in the interventricular septum. We report the case of a patient with a nonischemic left ventricular aneurysm presenting with a left ventricular outflow tract (LVOT) tachycardia and a right ventricular outflow tract (RVOT) tachycardia. Mapping from the anterior interventricular vein and the endocardium of the RVOT revealed mid-diastolic potentials at the epicardium of the LVOT and the endocardium of RVOT, where the criteria of central isthmus sites could be demonstrated. Ablation targeting an isolated late potential during sinus rhythm in RVOT eliminated both the LVOT tachycardia and the RVOT tachycardia. In this patient with a nonischemic left ventricular aneurysm, the substrate of a LVOT tachycardia and RVOT tachycardia is described, and successful catheter ablation of the right and left ventricular tachycardia from the septal wall of RVOT is reported.     

右室流出道室性心律失常的射频导管消融体会

目的报道右室流出道(RVOT)室性心律失常的射频导管消融(RFCA)体会。方法43例RVOT室性心律失常患者男18例、女25例,年龄39.2±15.1(13～67)岁。经血液生化、胸片、心脏彩超等检查证实无器质性心脏病证据。其中室性心动过速(VT)8例,室性早搏(PVC)35例。38例采用传统的起搏与激动标测。5例VT是在非接触标测系统EnSite3000指导下进行消融治疗的。结果①间隔部起源40例,游离壁起源3例。42例成功,1例失败,成功率97.7%,9例复发,再次标测消融后成功。②RVOT起源的VT和PVC具有典型的心电图特征,表现为典型的左束支传导阻滞型伴电轴右偏。RVOT的起源点不同,其12导联心电图特征不同,Ⅰ、Ⅱ、Ⅲ和aVF导联呈RR′型,V1～V3具有深S波是游离壁起源的特征。③1例术中出现急性心包压塞,其心电图虽具有RVOT起源的特征,但Ⅱ、Ⅲ和aVF导联R波振幅异常增高。结论RVOT室性心律失常具有典型的心电图和电生理特征,RFCA是一种安全、有效的治疗方法。EnSite3000非接触标测系统定位快速准确,适用于血流动力学不稳定的复杂性心律失常的标测。     

起源于左右心室流出道心动过速和早搏的射频导管消融治疗

目的 探讨射频导管消融（RFCA）治疗心室流出道特发性室性心动过速（室速）和室性早搏（室早）的临床效果、心电图及电生理特征。方法 58例患者中室速10例,室早48例。起源于右室流出道（RVOT）43例,左室流出道（LVOT）15例,其中起源于主动脉瓣上Valsalva左冠窦（LSV）12例。5例RVOT室速是在非接触标测系统Ensite3000指导下进行消融的。结果 （1）58例患者中55例成功,3例失败,9例复发。（2）其中1例患者术中出现急性心包压塞。（3）起源心室流出道的室速和室早具有典型的心电图特征,其中Ⅱ、Ⅲ、aVF导联单向R波是流出道室性心律失常的共同特点。（4）V1或V2导联的R波时限指数与R／S波幅指数可作为区别LSV与RVOT室速和室早的有效指标。结论 射频导管消融治疗心室流出道特发性室性心律失常是一种安全、有效的方法。非接触标测系统对于血流动力学不稳定的复杂性室性心律失常的标测与治疗具有重要的意义。     

Clinical usefulness of a multielectrode basket catheter for idiopathic ventricular tachycardia originating from right ventricular outflow tract

INTRODUCTION: It often is difficult to determine the optimal ablation site for idiopathic ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT) when the VT or premature ventricular complex (PVC) does not occur frequently. The aim of our study was to evaluate the usefulness of a multielectrode basket catheter for ablation of idiopathic VT originating from the RVOT. METHODS AND RESULTS: Radiofrequency (RF) catheter ablation was performed using a 4-mm tip, quadripolar catheter in 50 consecutive patients with 81 VTs originating from the RVOT with (basket group = 25 patients with 45 VTs) or without (control group = 25 patients with 36 VTs) predeployment of a multielectrode basket catheter composed of 64 electrodes. Deployment of the multielectrode basket catheter was possible and safe in all 25 patients in the basket group. Ablation was successful in 25 (100%) of 25 patients in the basket group and in 22 (88%) of 25 patients in the control group. The total number of RF applications and the number of RF applications per PVC morphology did not differ between the two groups. However, both the fluoroscopic and ablation procedure times per PVC morphology were shorter in the basket group than in the control group (36.8+/-14.1 min vs 52.0+/-32.5 min, P = 0.04; 60.0+/-14.6 vs 81.5+/-51.2 min, P = 0.05). This difference was more pronounced in the 29 patients in whom VT or PVC was not frequently observed. CONCLUSION: The multielectrode basket catheter is safe and useful for determining the optimal ablation site in patients with idiopathic VT originating from the RVOT, especially in those without frequent VT or PVC.     

Acute coronary artery occlusion and ischemia-related ventricular tachycardia during catheter ablation in the right ventricular outflow tract

Coronary artery injury is a rare complication of catheter ablation in the right ventricular outflow tract (RVOT). Furthermore, acute myocardial ischemia usually causes polymorphic ventricular tachycardia (VT) or ventricular fibrillation. We herein describe a case in which catheter ablation for VT originating from the RVOT provoked ischemia-related VTs due to acute occlusion of the left anterior descending artery.     

右心室间隔部希氏束附近室性期前收缩心电图与射频消融

目的 报道右心室流入道间隔部希氏束附近起源室性期前收缩体表心电图特征及射频消融效果。方法 无器质性心脏病频发性室性期前收缩5例,分析其12导联体表心电图室性期前收缩特点;病人接受心内电生理检查,于右心室流入道行激动与起搏标测,以心室激动较体表QRS波提早、消融导管远端起搏图形与体表心电图室性期前收缩相似部位为消融靶点。结果 室性期前收缩QRS波形态：5例病人Ⅰ导联和Ⅱ导联QRS波均呈R型,Ⅲ导联、aVF导联以低振幅波为主,V1导联均呈QS型,胸导联较早转变成qR或R型（发生于V2或V3）,V5、V6均呈高R型;室性期前收缩QRS波时限为110～120ms。5例病人分别于前间隔（2例）、中间隔（1例）、后间隔（2例）标测到消融靶点,放电后前间隔部、后间隔部病人室性期前收缩均消失,中间隔病人消融失败。无房室传导阻滞并发症。随访8～30个月,成功病例未应用抗心律失常药物,无室性期前收缩发作。结论 右心室流入道间隔部希氏束附近起源室性期前收缩体表心电图具有明显的特征,认识这些特征有助于导管标测与射频消融,消融此部位室性期前收缩安全、有效。     

Electrocardiographic predictors of failure and recurrence in patients with idiopathic right ventricular outflow tract tachycardia and ectopy who underwent radiofrequency catheter ablation

This study reports new electrocardiographic (ECG) predictors of radiofrequency catheter ablation failure and recurrence in idiopathic right ventricular outflow tract (RVOT) ventricular tachycardia (VT) or ectopy based on 91 consecutive patients. Procedural success and failure rates were 85% (77/91) and 15% (14/91), respectively. Twenty three percent (18/77) had recurrence during the follow-up period of 1 to 120 months (mean 56 +/- 31 months). Baseline RVOT VT/ectopy on 12-lead ECG taken prior to ablation from 91 patients were retrospectively analyzed. Ablation performed with RVOT ectopy (isolated ectopies, bigeminy, trigeminy, or couplets) as template arrhythmia was more likely to fail (30% vs. 8%, P =.02) as opposed to RVOT VT (sustained or nonsustained). VT/ectopy-QRS morphology variation was more observed in failed ablations (36% vs. 7%, P =.001). Significantly wider mean VT/ectopy QRS in leads I, II, AVR, V2, V3, V5, and V6 were noted in failed ablation group. Mean R wave amplitude reached statistical significance only in lead II (22.0 +/- 5.1 mV for failed vs. 17.8 +/- 5.2 mV for successful outcomes; P =.009). QRS morphologic variation (47% vs. 16%; P =.009) was the only statistically significant ECG to be more common in patients with arrhythmia recurrence. In conclusion, ablation with ectopy over VT as template arrhythmia, presence of QRS morphologic variation, wider mean QRS width, and taller mean R-wave amplitude in lead II were identified ECG predictors of failed RVOT VT/Ectopy ablation. The only ECG predictor of recurrence was the presence of RVOT VT or ectopy QRS morphologic variation.     

Electroanatomic mapping characteristics of ventricular tachycardia in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia.

BACKGROUND: Ventricular tachycardia (VT) in arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVD) has been previously explored using entrainment mapping techniques but little is know about VT mechanisms and the characteristics of their circuits using an electroanatomical mapping system. METHODS AND RESULTS: Three-dimensional electroanatomical mapping was performed in 11 patients with well tolerated sustained VT and ARVD. Sinus rhythm mapping of the right ventricle was performed in eight patients showing areas of low bipolar electrogram voltage (<1.2 mV). In total 12 tachycardias (mean cycle length 382+/-62 ms) were induced and mapped. Complete maps demonstrated a reentry mechanism in eight VTs and a focal activation pattern in four VTs. The reentrant circuits were localized around the tricuspid annulus (five VTs), around the right ventricular outflow tract (one VT) and on the RV free lateral wall (two VTs). The critical isthmus of each peritricuspid circuit was bounded by the tricuspid annulus with a low voltage area close to it. The isthmus of tachycardia originating from the right ventricular outflow tract (RVOT) was delineated by the tricuspid annulus with a low voltage area localized on the posterior wall of the RVOT. Each right ventricular free wall circuit showed an isthmus delineated by two parallel lines of block. Focal tachycardias originated on the right ventricular free wall. Linear radiofrequency ablation performed across the critical isthmus was successful in seven of eight reentrant tachycardias. The focal VTs were successfully ablated in 50% of cases. During a follow-up of 9-50 months VT recurred in four of eight initially successfully ablated VTs. CONCLUSIONS: Peritricuspid ventricular reentry is a frequent mechanism of VT in patients with ARVD which can be identified by detailed 3D electroanatomical mapping. This novel form of mapping is valuable in identifying VT mechanisms and in guiding RF ablation in patients with ARVD.     

起源点邻近房室瓣环的特发性室性心律失常体表心电图特点及射频消融治疗

目的 评估起源点邻近房室瓣环附近的室性心动过速和室性早搏(室速/室早)的体表心电图特点及射频消融治疗效果.方法 共19例特发性室速/室早患者接受常规电生理检查及射频消融治疗,对所有病例12导联体表心电图进行分析.结果 19例室速/室早术中均消融成功.10例起源于二尖瓣环附近,包括前侧壁(5例)、后侧壁(3例)、后间隔(2例).9例起源于三尖瓣环附近,包括游离壁侧5例、间隔侧4例.对各组瓣环室速/室早心电图做进一步分析,可概括出系列心电图判断指标用以估计消融靶点的部位.结论 起源点邻近房窜瓣环附近的室速/窒早是特发件室速/室早的一个亚组,射频消融治疗可取得良好效果,掌握其体表心电图特点有助于判定室速/室早的起源部位.     

左束支阻滞型特发性室性心动过速的心电图特征对射频消融成功的影响初探

对心电图呈左束支阻滞型的特发性室性心动过速 (简称室速 )的临床特点和心电图进行分析 ,以了解哪些因素可以预测此类患者从右室流出道行射频消融的成功率。对 2 6例特发性室速的患者进行电生理检查和射频消融手术 ,全部患者室速时的心电图呈左束支阻滞。结果 :2 6例中 ,2 2例于右室流出道进行了成功消融 ,成功和未成功消融的患者临床特征和电生理无明显区别 ,成功消融的患者中胸前V1 导联心电图呈rS型 (1 2例 )和QS型 (1 0例 ) ,而 4例未成功者 ,V1 导联均呈rS型 ,其中 2例经主动脉于左冠状窦消融成功。在成功与未成功消融患者中 ,V1 导联有无R波无明显区别 ,但V1 导联无R波预示室速可以从右室流出道成功消融 ,成功消融的室速患者胸前导联的平均移行区在V4导联 ,而未成功患者胸前导联的移行区在V3 或V2 导联。结论 :某些心电图呈左束支阻滞 ,且额面电轴正常或右偏的特发性室速患者不能成功从右室流出道消融 ,V1 导联有r波且移行区在V3 导联或之前者提示此类心电图特征的室速可能非起源于右室流出道 ,部分可能起源于左室流出道     

非接触球囊标测指导血流动力学不稳定性或非持续性室性心动过速的射频消融

目的探讨非接触球囊标测在指导血流动力学不稳定性或非持续性室性心动过速(室速)射频消融中的作用。方法17例室速患者,年龄50岁±9岁,经心室刺激诱发血流动力学不稳定性或非持续性室速后,使用非接触标测系统ENSITE3000标测室速的出口和(或)慢传导区,然后使用温控大头导管在室速出口作环形消融或横跨慢传导区进行线性消融。结果17例患者共诱发18次室速,周长为336MS±58MS。15例患者可确定室速的出口,为QRS波前10MS±16MS;其中5例是心肌梗死后室速,9例为右室流出道室速。5例心肌梗死后室速均可确定舒张期慢传导区,最早的心内膜舒张期电活动在QRS波前60·1MS±42·6MS。3例非持续性室速均可确定最早的心室激动点。18次室速中15次消融成功,1例没有进行消融,2例消融失败。结论非接触球囊心内膜标测能成功指导血流动力学不稳定性或非持续性室速的射频消融。     

Localization of breakthrough site of canine monomorphic ventricular tachycardia by pacemapping. A vectorial approach

BACKGROUND. The precision and limitations of ventricular pacemapping as a method to localize the site of earliest breakthrough of ventricular tachycardia (VT) were investigated in a canine model of experimental myocardial infarction. METHODS AND RESULTS. Forty-one episodes of VT induced in 10 animals were mapped using a standard grid of 64 endocardial and epicardial bipolar electrodes to determine the site of earliest endocardial or epicardial breakthrough of activation during VT. Each of these 64 recording sites was also used for ventricular pacing during sinus rhythm at cycle lengths comparable to those of the VTs. Orthogonal X, Y, and Z Frank electrocardiographic (ECG) leads were recorded during all episodes of VT and ventricular pacing from all sites after the chest was closed in all animals. Surface ECG waveforms corresponding to each VT and each ventricular pacing were compared pairwise by measuring the Euclidean metric difference between the VT and ventricular pacing vectors with the orthogonal ECG leads as their X, Y, and Z components. The pacing site that generated the vector most similar to VT vector (smallest vectorial difference) was defined as the predicted breakthrough site. This predicted site of breakthrough was identical to the actual site of breakthrough determined by activation sequence mapping during VT for only nine VTs (22%). However, for an additional 27 VTs (66%), the observed and predicted breakthrough locations were at adjacent (1 cm or less apart) recording sites. For five VTs (12%), the two sites were remote, the distance between them exceeding 1 cm. CONCLUSIONS. In this model, locating the breakthrough site by pacemapping is exact in only a small minority of VTs. However, when orthogonal surface ECG leads are used for comparison, pacemapping can predict the site of earliest breakthrough during VT with a 1-cm resolution in the majority of VTs.     

Multiple macroreentrant ventricular tachycardias exhibiting centrifugal endocardial activations from the scar border zone after myocardial infarction

A 53-year-old man with a ventricular tachycardia (VT) electrical storm during the chronic phase of an extensive anteroseptal myocardial infarction underwent electrophysiologic testing and catheter ablation. An electroanatomical map during 7 induced macroreentrant VTs demonstrated multiple centrifugal endocardial activations from sites that were located at the circumferential border zone of a large scar area. Interestingly, during the radiofrequency catheter ablation of 4 of the VTs, the elimination of the substrate of the previous VTs converted one VT to another probably because those VTs might have shared a central common pathway of the macroreentrant circuit with different exits.     

射频消融治疗特发性室性心动过速疗效观察

目的 :评价射频消融术治疗特发性室性心动过速 (室速 )临床疗效。方法 :5 6例特发性室速患者中 ,34例左室特发性室速采用EPT小、中弯大头导管 (或Webstr小弯大头 ) ,在左室行激动顺序标测和消融 ,以P电位较QRS起点提前 2 0ms以上作为消融靶点。 2 2例右室流出道室速采用Webster加硬导管在右室流出道行起搏标测 ,以起搏时与心动过速时体表 12导联QRS形态完全相同或最接近处为消融靶点 ,成功标准为放电过程中心动过速终止且不能诱发。结果 :5 1例患者消融成功 ,成功率 91.1%。 34例左室特发性室速中 30例靶点位于左室间隔中下部 ,2例近左室心尖 ,1例左室流出道 ,1例位于间隔高位。 31例消融成功 ,1例失败 ,2例因导管到达间隔处机械刺激终止室速而不能再诱发 ,于终止室速处作为靶点射频消融 ,1例于术后第 2天、另 1例半年后室速复发。 2 2例右室流出道室速 ,16例位于流出道间隔侧 ,6例位于流出道游离侧壁。 19例起搏标测到与心动过速 12导联QRS形态完全相同靶点 ,1例形态接近 ,消融获成功。 2例未能诱发室速 ,射频消融 1个月心动过速重新出现 ,所有患者无并发症出现。结论 :射频消融术对特发性室速是一种安全有效的治疗方法 ,可作为首选治疗。电生理未诱发室速或机械刺激终止室速不宜尝试射频消融治疗。     

Radiofrequency catheter ablation of ventricular tachycardia in a patient with dermatomyositis

Dermatomyositis is an idiopathic systemic inflammatory disorder that rarely affects the cardiac muscles. It has shown to be associated with various arrhythmias frequently manifesting as conduction disturbances. There are few case reports regarding dermatomyositis and ventricular tachyarrhythmias. Moreover, data regarding clinical experiences and outcome of radiofrequency catheter ablation (RFCA) for ventricular tachycardia (VT) in dermatomyositis is limited. We report a 51-year old male patient with dermatomyositis presented at our hospital for recurrent palpitation caused by VT.The VT was isoproterenol-triggered, adenosine-suppressed, and focally originating from the posteroinferior right ventricular septal area. The most likely mechanism is abnormal automaticity. A successful 3D-electroanatomical mapping-guided RFCA at the earliest activation sites cured VTs with no recurrence. It suggests that RFCA is safe and effective for focal VTs in dermatomyositis patients.