Coronary sinus mapping to differentiate left versus right ventricular outflow tract tachycardias.

Outflow tract ventricular tachycardia (OT-VT) can originate from several different segments of the outflow tract. Various ECG criteria have been proposed for localization of OT-VTs. We present two patients, one with left and one with right OT-VT. We used local ventricular electrograms in the coronary sinus to localize the focus of the OT-VT. Mapping of local ventricular electrograms in the coronary sinus may be a simple and effective method for differentiating right versus left ventricular outflow tract tachycardias. However, the diagnostic value and precision of this method should be evaluated in a series of patients before its implementation in the OT-VT ablation decision algorithm.     

Coexistence of 2 types of atrial tachycardias and right ventricular outflow tract tachycardia

Double tachycardia is a relatively uncommon type of tachycardia. In this report, we discuss a 68-year-old woman with history of frequent palpitations. Electrophysiologic study revealed that narrow QRS tachycardias from 2 origins and 1 wide QRS tachycardia were induced and each of the tachycardias was induced by the other. We found that 2 focal atrial tachycardias and 1 ventricular tachycardia originated from right ventricular outflow tract. All of these tachycardias were successfully ablated during one session, and no recurrence appeared during 10 months of follow-up.     

Left ventricular outflow tract tachycardia originating from the right coronary cusp: identification of location of origin by endocardial noncontact activation mapping from the right ventricular outflow tract

Idiopathic left ventricular outflow tract (LVOT) tachycardia has been shown to originate from a supravalvular site in some patients. Considerable attention recently has focused on identifying this variant of LVOT tachycardia on 12-lead ECG. We report the case of 15-year-old boy in whom a noncontact three-dimensional mapping electrode deployed in the right ventricular outflow tract (RVOT) assisted in identifying a supravalvular LVOT tachycardia. Observation of two early breakthrough sites in the RVOT and right ventricular septum suggested a right aortic cusp origin of the tachycardia. Pace mapping in the right aortic cusp identified a successful ablation site.     

Automatic activation mapping and origin identification of idiopathic outflow tract ventricular arrhythmias

Purpose

Activation mapping is used to guide ablation of idiopathic outflow tract ventricular arrhythmias (OTVAs). Isochronal activation maps help to predict the site of origin (SOO): left vs right outflow tract (OT). We evaluate an algorithm for automatic activation mapping based on the onset of the bipolar electrogram (EGM) signal for predicting the SOO and the effective ablation site in OTVAs.

Spatial resolution of pacemapping and activation mapping in patients with idiopathic right ventricular outflow tract tachycardia

BACKGROUND: The purpose of this study was to compare the spatial resolution of activation mapping and pacemapping in patients undergoing ablation of idiopathic ventricular tachycardia (VT) arising from the right ventricular outflow tract (RVOT). A direct comparison of the two techniques has not been undertaken. METHODS AND RESULTS: Electroanatomical activation maps of the RVOT were obtained during VT in 15 patients. Pacemaps were obtained from multiple sites, tagged on the activation map, and scored according the degree of concordance between the paced QRS configuration and that of VT. The site of successful ablation was considered the VT site of origin. Initial endocardial activation away from the site of origin was rapid; the mean area of myocardium activated within the first 10 msec (early activation area, EAA) was 3.0 +/- 1.6 cm(2) (range: 1.3-6.4 cm(2)). Best pacemap scores were always obtained adjacent to the site of origin. Pacemap concordance, and the probability of an exact pacemap match significantly decreased with increasing distance of the pacing site from the site of origin (P < 0.01). All patients had more than one pacing site yielding a best pacemap score. The greatest distance between such sites in an individual patient ranged from 11 to 26 mm (mean: 18 +/- 5 mm), and was strongly correlated with the size of the EAA (r = 0.77, P < 0.001). CONCLUSIONS: Pacemapping and activation mapping provide similar localizing information. The spatial resolution of each technique is modest, varies between patients, and may be optimized by three-dimensional data display.     

Long-term follow-up of right ventricular outflow tract septal pacing

Objective Right ventricular outflow tract septum has become widely used us an electrode placement site. However, data concerning lead performances and complications for lead repositioning with this technique were scant. The purpose of this study was to observe long- term lead performances and complications of right ventricular outflow tract septal pacing and provide evidences for choosing an optimal electrode implantation site. Methods Thirty-six patients with septal active electrode implantation and 39 with apical passive electrode implantation were enrolled in this study. Pacing threshold, R-wave sensing, lead impedance, pacing QRS width and pacing-related compli- cations for two groups at implantation and follow-up were compared. Results There were higher pacing threshold and shorter pacing QRS width at implantation in the septal group compared with the apical group. There were no differences between the septal and the apical groups in pacing threshold, R-wave sensitivity, lead impedance and pace-related complication during a follow-up. Conclusions Right ventricular outflow tract septum could be used as a first choice for implantation site because it had long-term stable lead performances and no serious complications compared with the traditional apical site.     

Evaluation and management of ventricular outflow tract tachycardias

Ventricular tachycardia (VT) arising from the right or left ventricular outflow tract (OT) is a recognized arrhythmia in individuals with structurally normal hearts. Treatment options for OTVT include medications, ablation and, rarely, an implantable cardioverter defibrillator (ICD). In the past few years ablation techniques have developed to the point where most OTVTs can be successfully ablated. However, a percentage of cases have remained where ablation is unsuccessful. Some of these cases may represent an epicardial focus of the VT. Several approaches to epicardial VT ablation have been described. We recently described a LVOT-VT variant, which may be epicardial in nature, in a group of patients in whom prior ablation attempts had failed. A trans-aortic ablation approach to outflow tract VT was successful in these patients.     

右心室流出道间隔部起搏与心尖部起搏的血流动力学对比研究

目的比较右心室流出道间隔部(RVOTS)与右心室心尖部(RVA)起搏对血流动力学的影响,评价RVOTS起搏的可行性。方法 53例需植入永久起搏器患者,均采用抑制型按需心室起搏模式(VVI),其中RVA起搏28例,RVOTS 25例。随访3～10个月,采用超声心动图检查方法检测血流动力学参数,包括LVEF、左室内径缩短分数(FS)、心输出量(CO)、心脏指数(CI),研究RVOTS与RVA起搏的术前、术后血流动力学差异。结果所有患者心室起搏保证在80%以上,与手术前比较,RVOTS起搏时,LVEF、FS、CO、CI分别下降了3.46%±3.89%、1.20%±2.47%、(0.19±1.32)L/min、(0.09±0.52)L·min~(-1)·m~(-2),差异无统计学意义(均为P>0.5)。与手术前比较,RVA起搏时LVEF、FS、CO、CI分别下降了14.27%±5.83%、8.10%±3.79%、(1.56±1.11)L/min、(1.13±0.52)L·min~(-1)·m~(-2)(均为P<0.01),RVOTS起搏与RVA起搏相比LVEF、Fs、CO、CI明显改善(均为P<0.05),且临床症状明显减轻。结论 RVOTS起搏对血流动力学无明显不良影响。     

电极导线在右室心尖部和右室流出道起搏的随访观察

目的评价螺旋电极导线行右室流出道(RVOT)间隔部起搏的可行性。方法连续入组195例具有植入起搏器适应证患者,术前随机分为螺旋主动固定电极导线的RVOT间隔起搏组(A组)和翼状被动固定电极导线的右室心尖部(RVA)起搏组(B组),两组中每例入选患者均分别行RVA和RVOT两个部位起搏测试,最后固定于相应的位置。比较两组术中手术时间、起搏参数、起搏QRS波宽度、手术成功率及起搏3个月、1年和2年后电极导线参数的变化。结果 A组99例,B组96例。两组起搏后QRS波宽度明显大于起搏前,B组起搏QRS波时限长于A组(176.46±24.54 ms vs 165.45±22.78 ms,P=0.001)。用于固定RVOT间隔部的曝光时间长于RVA。两组术中及术后并发症相似,R波振幅术后2年内及两组间无差别。术中A组起搏阈值高于B组(0.71±0.30 V vs0.56±0.19 V),术后2年内起搏阈值两组内及组间无差异。术后3个月时阻抗下降,A组的阻抗低于B组并持续整个随访期间。术后2年内超声心动图参数组内及组间无差别。结论采用螺旋主动固定电极导线进行RVOT起搏是安全可行的。     

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.     

Endocardial mapping of right ventricular outflow tract tachycardia using noncontact activation mapping

INTRODUCTION: Activation mapping and pace mapping identify successful ablation sites for catheter ablation of right ventricular outflow tract (RVOT) tachycardia. These methods are limited in patients with nonsustained tachycardia or isolated ventricular ectopic beats. We investigated the feasibility of using noncontact mapping to guide the ablation of RVOT arrhythmias. METHODS AND RESULTS: Nine patients with RVOT tachycardia and three patients with ectopic beats were studied using noncontact mapping. A multielectrode array catheter was introduced into the RVOT and tachycardia was analyzed using a virtual geometry. The earliest endocardial activation estimated by virtual electrograms was displayed on an isopotential color map and measured 33 +/- 13 msec before onset of QRS. Virtual unipolar electrograms at this site demonstrated QS morphology. Guided by a locator signal, ablation was performed with a mean of 6.9 +/- 2.2 radiofrequency deliveries. Acute success was achieved in all patients. During follow-up, one patient had a recurrence of RVOT tachycardia. Compared with patients (n = 21) who underwent catheter ablation using a conventional approach, a higher success rate was achieved by noncontact mapping. Procedure time was significantly longer in the noncontact mapping group. Fluoroscopy time was not significantly different in the two groups. CONCLUSION: Noncontact mapping can be used as a reliable tool to identify the site of earliest endocardial activation and to guide the ablation procedure in patients with RVOT tachycardia and in patients with ectopic beats originating from the RVOT.     

Arrhythmogenic right ventricular dysplasia presenting as right ventricular outflow tract tachycardia.

A case of a 51-year old male is presented. A left bundle branch block inferior axis tachycardia was manifest. At electrophysiological study this tachycardia was inducible and was ablated in the septal right ventricular outflow tract (RVOT). Two other tachycardias were identified both with right bundle branch block (RBBB) morphology raising the suspicion of diffuse pathology. Arrythmogenic right ventricular dysplasia (ARVD) was confirmed by right ventricular angiography and magnetic resonance imaging (MRI). An implantable cardioverter defibrillator (ICD) was implanted and an appropriate shock was later delivered.     

Electrocardiographic features of failed and recurrent right ventricular outflow tract catheter ablation of idiopathic ventricular arrhythmias

1 Introduction

Various ECG algorithms have been proposed to identify the origin of idiopathic outflow tract (OT)‐ventricular arrhythmia (VA). However, electrocardiographic features of failed and recurrent right ventricular outflow tract (RVOT) ablation of idiopathic OT‐VAs have not been clearly elucidated.

2 Methods and results

A total of 264 consecutive patients (mean age: 44.0 ± 13.0 years, 96 male) undergoing RVOT ablation for OT‐VAs with a transition ≥V₃, including 241 patients (91.6%) with initially successful procedures and 23 patients (8.4%) with failed ablation. Detailed clinical characteristics and ECG features were analyzed and compared between the two groups. VAs with failed RVOT ablation had larger peak deflection index (PDI), longer V₂ R wave duration (V₂Rd), smaller V₂ S wave amplitude, higher R/S ratio in V₂, higher V₃ R wave amplitude, and larger V₂ transition ratio than those with successful ablation. Multivariate analysis demonstrated that PDI, V₂Rd, V₂ transition ratio, and pacemapping score acquired during mapping independently predicted failed ablation (P  =  0.01, P  =  0.01, P  =  0.01, and P < 0.001, respectively). In 31 recurrent cases (12.8%) after initially successful ablation, multivariate Cox regression analysis showed that only the earliest activation time acquired during mapping predicted the recurrences after successful ablation (P  =  0.001). The recurrent cases displayed different ECG features comparing with those with failed ablation.

3 Conclusion

The electrocardiographic features of failed RVOT ablation of idiopathic OT‐VAs with a transition ≥V₃ were characterized by PDI, V₂Rd, V₂ transition ratio, and pacemapping score acquired during mapping, unlike the recurrent RVOT ablation.     

体表心电图特征对特发性右心室流出道室性心动过速和室性早搏起源点的定位价值

目的 起源于右心室流出道(RVOT)不同位点的室性心动过速(VT)具有相应的心电图表现,本研究旨在摸索一种相对简单的根据体表心电图进行定位的方法 .方法 将RVOT分为游离壁和间隔而两大区,其中间隔面又分为9个区域.共320例RVOT-VT患者中,对213例既往消融成功患者的靶点与体表12导联心电图中QRS波形态之间的关系进行分析,并在消融前前瞻性地对另外107例患者的消融靶点进行预测,以检验其定位价值.结果 I导联对RVOT起源的VT有特殊的定位价值.在间隔面前部起源时,I导联以负向波为主,多为QS、Qr及rS型,随着起源点从前向后、从上向下,R波逐渐升高,其中起源于间隔侧中带(2、5、8区)时,以"M"型居多,在后壁时则表现为R波且有切迹.游离壁起源者的QRS时限明显延长,I和aVL导联的R波较间隔起源者高,而下壁导联的R波均较间隔的低(P<0.05).在前瞻性分析中,这些参数的敏感度、特异度、阳性和阴性预测值均较高.结论 RV-OT不同部位起源的VT有相应的心电图特征,其中I导联形态尤其具有定位价值,为RVOT心律失常起源提供了简便的定位标准.     

低能量放电下标测无室性早搏的流出道室性心动过速

目的 本文报道11例非频发室性早搏(室早)的流出道室性心动过速(室速)伴反复晕厥病例经导管射频消融成功的体会,并由此介绍一种新的针对这类患者的标测方法.方法 11例患者,全部为女性,年龄(39.9±13.7)岁,全部曾使用2种以上抗心律失常药物治疗,治疗期间均有晕厥或黑矇病史1～3年.结果 (1)所有11例患者在术中经过各种方法均可记录到至少1次室早、室速发作心电图,其中6例经程序刺激不能诱发的通过静脉滴注异丙肾上腺素能诱发室早、室速.(2)所有患者先在右心室流出道预测起源区以15～20 W低能量放电下微调消融电极导管位置和方向,在诱发出与所记录、冻结的室早完全一致的位点时,加大能量至35～50 W,反复巩固2～3次,直至室早、室速不再出现.然后以此点为中心,向周围微移动电极导管约5 mm,最终消融出大约1 cm2的面积.所有11例患者,采用这种方法全部都诱发出与记录室早12/12导联完全一致的室速.(3)11例患者中有10例达到消融终点,其中9例在右心室流出道间隔部及后壁,1例在右冠窦基底部.另1例未达到消融终点的患者,在消融开始时用异丙肾上腺素仅可诱发极少的室早,但在低能量消融后诱发频发的短阵室速,激动标测提示最早激动点位于左冠窦中下部,该处放电诱发出与自发室早一致的图,但反复放电室早、室速不能完全消除,考虑为靠外膜区室早而放弃.(4)术后所有患者经电话、预约门诊随访3～14个月,没有1例主诉再发黑矇和晕厥者.结论 低能量放电标测完全可作为一种新的标测手段在实际工作中配合使用,尤其对那些反复黑矇、晕厥但室早、室速发作较少的患者,常规标测方法几乎无用,此时低能量放电标测就显得更加实用.     

Cryocatheter ablation of right ventricular outflow tract tachycardia

INTRODUCTION: Cryocatheter techniques have been successfully applied to treat supraventricular tachycardia but there are no reports on their value in treating ventricular tachycardia (VT). We present our initial experience with cryocatheter ablation of right ventricular outflow tract (RVOT) tachycardia. METHODS AND RESULTS: Cryocatheter ablation was attempted in 14 patients (13 females, age 45.9 +/- 12.7 years) who were highly symptomatic due to frequent monomorphic ventricular extrasystole (VES) or nonsustained VT originating within the RVOT. A 9-Fr, 8-mm-tip cryocatheter was used for both mapping and ablation. Cryoablation was started after localizing the arrhythmic focus by pace and activation mapping. Ablation success, defined by complete disappearance of target VES/VT acutely and during a follow-up of 9.3 +/- 1.4 weeks, was achieved in 13 of 14 patients. Ablation was successful with local activation times of 35 +/- 4 ms, 5.8 +/- 3.3 applications, 18.8 +/- 7.5 minutes total cryo time, 9.4 +/- 4.2 minutes fluoroscopy time, and 66.9 +/- 26.1 minutes total procedure time, the latter two measures showing a reduction with number of patients treated. Three patients reported slight pain related to local pressure of the catheter on the RVOT wall. No pain was described related to delivery of cryothermal energy. CONCLUSIONS: Initial experience shows that focal VES/VT originating in the RVOT can be successfully treated using cryocatheter ablation. Acute and short term success rates, fluoroscopy times, and duration of procedure are comparable to conventional ablation techniques. A major advantage seems to be the virtual absence of ablation related pain.