Remote magnetic catheter mapping and ablation of permanent junctional reciprocating tachycardia in a seven-year-old child

Background: Mapping and catheter ablation of permanent junctional reciprocating tachycardia (PJRT) in children can be challenging. Remote magnetic navigation may improve precise mapping and catheter stability during ablation, as well as reduce fluoroscopy time, especially in conjunction with a non-fluoroscopic mapping system.
Objective: We report a case of PJRT ablation in a 7-year-old child using remote magnetic navigation.
Methods and Results: Mapping of the right atrium (RA) and the coronary sinus (CS) and catheter ablation were performed using remote magnetic navigation in conjunction with a non-fluoroscopic mapping system (NavX®). We observed excellent catheter steering abilities and constant wall contact during ablation, allowing a short and safe procedure.
Conclusions: Remote magnetic navigation may be used for mapping and ablation of PJRT in children.     

磁导航系统遥控导管消融治疗右心室流出道室性心动过速/室性早搏

目的：探讨应用磁导航遥控导管消融治疗右心室流出道起源的室性心动过速/室性早搏（ RVOT-VT/PVCs）的安全性和有效性。方法2008年11月至2009年11月,在南京医科大学第一附属医院心血管内科行体表心电图检查,诊断为RVOT-VT/PVCs的患者共16例[女12例,男4例,平均年龄（44±15）岁],结合应用非接触标测系统和起搏标测确定靶点,磁导航遥控磁导管实施消融术,消融失败者改为手控导管消融。结果10例（63%）患者使用磁导航消融成功,6例需手控导管消融,1例术后出现动静脉瘘。平均放电（3．9±1．6）次,放电时间（240±33） s,总手术时间为（190±42） min,总X线曝光时间为（4．8±2．6） min,术者X线曝光时间平均为（3．2±2．0） min,磁导航系统遥控导管X线曝光时间为（1．6±1．0） min。结论应用磁导航系统结合非接触标测系统可安全、有效地实施遥控导管消融治疗RVOT-VT/PVCs,并可减少术者和患者的X线曝光时间。     

Remote magnetic navigation for mapping and ablating right ventricular outflow tract tachycardia

BACKGROUND: Navigation, mapping, and ablation in the right ventricular outflow tract (RVOT) can be difficult. Catheter navigation using external magnetic fields may allow more accurate mapping and ablation. OBJECTIVES: The purpose of this study was to assess the feasibility of RVOT tachycardia ablation using remote magnetic navigation. METHODS: Mapping and ablation were performed in eight patients with outflow tract ventricular arrhythmias. Tachycardia mapping was undertaken with a 64-polar basket catheter, followed by remote activation and pace-mapping using a magnetically enabled catheter. The area of interest was localized on the basket catheter in seven patients in whom an RVOT arrhythmia was identified. Remote navigation of the magnetic catheter to this area was followed by pace-mapping. Ablation was performed at the site of perfect pace-mapping, with earliest activation if possible. RESULTS: Acute success was achieved in all patients (median four applications). Median procedural time was 144 minutes, with 13.4 minutes of patient fluoroscopy time and 3.8 minutes of physician fluoroscopy time. No complications occurred. One recurrence occurred during follow-up (mean 366 days). CONCLUSION: RVOT tachycardias can be mapped and ablated using remote magnetic navigation, initially guided by a basket catheter. Precise activation and pace-mapping are possible. Remote magnetic navigation permitted low fluoroscopy exposure for the physician. Long-term results are promising.     

Electrocardiographic Characteristics of Ventricular Arrhythmias Arising from the Aortic Sinuses of Valsalva: A Case Report and Review of the Literature

We describe a patient with frequent, symptomatic, and drug-refractory premature ventricular contractions (PVCs) with a right bundle branch block, inferior axis morphology suggestive of a left ventricular outflow tract (LVOT) origin. Successful ablation of the PVCs was performed from the left coronary cusp of the aortic valve. We discuss our patient and review the literature regarding patients with ventricular arrhythmias arising from the coronary cusps, with special emphasis on the use of the electrocardiogram to aid localization of the focus.     

射频消融治疗起源于左室流出道的非持续性室性心动过速和频发性室性早搏

目的观察左室流出道非持续性室性心动过速（室速）和频发性室性早搏患者的射频消融治疗结果,探讨此类患者的射频消融指证。方法５例患者因非持续性室速和频发性室性早搏而引起明显临床症状,药物治疗无效。采用起搏标测法确定室速和室性早搏的起源部位,并射频消融治疗。结果在升主动脉瓣左窦下方的左室流出道记录到提前（３１±４）ｍｓ的心室激动,起搏心电图１２导联ＱＲＳ波形与室速和室性早搏形态完全相同者４例,１１导联相同者１例,该部位消融后５例患者的室速和室性早搏不被诱发。随访１３±６个月,除１例患者复发,另４例的临床症状明显改善。结论射频消融治疗左室流出道非持续性室速和室性早搏安全有效,但应严格掌握适应证。     

Magnetic Navigation and Catheter Ablation of Right Atrial Ectopic Tachycardia in the Presence of a Hemi-Azygos Continuation: A Magnetic Navigation Case Using 3D Electroanatomical Mapping

Introduction: We report on a 63-year-old female patient in whom an electrophysiologic study discovered a hemi-azygos continuation. Using the magnetic navigation system, remote-controlled ablation was performed in conjunction with the 3D electroanatomical mapping system.
Methods and Results: Failing the attempt to advance a diagnostic catheter from the femoral vein, a diagnostic catheter was advanced via the left subclavian vein into the coronary sinus. The soft magnetic catheter was positioned in the right atrium via the hemi-azygos vein, and 3D mapping demonstrated an ectopic atrial tachycardia. Successful ablation was performed entirely remote controlled. Fluoroscopy time was only 7.1 minutes, of which 45 seconds were required during remote navigation.
Conclusion: Remote-controlled catheter ablation using magnetic navigation in conjunction with the electroanatomical mapping system proved to be a valuable tool to perform successful ablation in the presence of a hemi-azygos continuation.     

How to diagnose,locate, and ablate coronary cusp ventricular tachycardia

INTRODUCTION: Although radiofrequency energy usually is applied to the most favorable endocardial site in patients with outflow tract ventricular tachycardia, there are still some patients in whom the tachycardia can be ablated only from an epicardial site. We established the characteristics and technique of catheter ablation from both the left and right coronary cusps to cure left ventricular outflow tract ventricular tachycardia. METHODS AND RESULTS: We studied 15 patients in whom VT was thought to originate from the coronary cusp by both activation and pace mapping after precise mapping of the right ventricle, left ventricle, pulmonary artery, coronary cusps, and anterior interventricular vein. Twelve-lead ECG analysis revealed an S wave on lead I, tall R wave on leads II, III, and aVF, and no S wave on either lead V5 or V6. Precordial R wave transition occurred on leads V1 and V2. The earliest ventricular electrogram at a successful ablation site was recorded 35+/-12 msec before QRS onset and 19+/-15 msec earlier than the earliest ventricular electrogram recorded from the anterior interventricular vein. Almost identical pace mappings were obtained from the coronary cusp. Catheter tip temperature was maintained at 55 degrees C during energy delivery, and the distance from the tip to the ostium of each left and right coronary artery was > 1.0 cm by coronary angiography. CONCLUSION: Left ventricular outflow tract VT that could not be ablated from an endocardial site could be safely eliminated by radiofrequency application to the left and right coronary cusps.     

射频消融治疗起源于主动脉根部室性早搏的临床观察

目的通过主动脉根部室性早搏（室早）的成功消融,对其机制及复发因素、心电图进行分析。方法10例左心室流出道室早患者,通过激动及起搏标测,准确定位并成功消融,证实起源于主动脉根部。消融术前、术后均行超声心动图检查,术中行腺苷试验及造影,术后随访6个月。结果10例患者中4例起源于主动脉根部左冠状动脉窦,2例起源于右冠状动脉窦,2例起源于左、右冠状动脉窦交界处,1例起源于无冠窦,1例起源于左冠状动脉窦心外膜,均成功消融。应用异丙肾上腺素后有1例诱发出同样室早,成功率90％。消融后有1例复发（10％）。结论主动脉根部室早多起源于左冠状动脉窦,根据体表心电图形态,结合腔内标测能准确定位,成功消融。     

EnSiteNavX三维标测系统指导主动脉窦起源的室性心律失常的消融

目的对主动脉窦起源的室性心律失常进行标测和消融需要准确和安全。本研究尝试采用EnSiteNavX标测技术对起源于主动脉窦的室性心动过速（室速）和／或室性早搏（室早）进行消融。方法运用NavX标测系统构建主动脉窦、升主动脉及冠状动脉开口的三维电解剖及激动顺序图,同时进行冠状动脉造影,以确认NavX导航的准确性。结合传统的电生理标测,射频消融治疗24例主动脉窦起源的室早和／或室速。结果24例均射频消融成功,其中,左冠窦内起源16例,右冠窦内起源4例,左、右冠窦问起源4例,术中和术后无并发症。消融时间及x线曝光时间（包括冠状动脉造影时间）分别为（56．1±18．3）min、（11．2±6．8）min。1例患者消融前发现合并左旋支中段狭窄,消融术后成功行支架术。平均随访（16_＋12）个月,1例室速患者有室早复发,再次消融成功。结论NavX标测技术可以代替冠状动脉造影,指导主动脉窦起源的室早和／或室速的标测和消融。     

应用磁导航技术遥控标测和消融治疗快速性心律失常

目的在数种快速性心律失常中,观察应用磁导航技术行遥控标测和消融治疗的可行性与安全性。方法对复杂程度不同的心律失常患者,采用NiobeII磁导航系统(Stereotaxis,Inc)遥控操作,用HeliosII磁性标测和消融导管行射频温控消融治疗。结果12例入选,男8例,女4例,年龄36.83±13.05岁。4例有晕厥,1例有心脏骤停,5例有器质性心脏病。房室结折返性心动过速3例,左前游离壁房室旁道3例,右游离壁房室旁道1例,左后间隔房室旁道伴心房颤动1例,左中间隔房室旁道伴房室结折返性心动过速1例,心房扑动1例,房性早搏/心房颤动1例,室性早搏/心室颤动1例。采用遥控操作,12例均完成电生理检查,11例可准确到达靶点部位,行射频消融,10例成功。操作时间149.17±68.95min,未见并发症。结论对复杂程度不同的心律失常,不管患者有无器质性心脏病,采用磁导航技术均可安全与可靠地实施遥控标测和消融治疗。     

射频导管消融治疗左心室流出道室性期前收缩的临床观察

目的 探讨左心室流出道室性期前收缩射频导管消融治疗的方法 及可行性. 方法 选择左心室流出道室性期前收缩 24例,采用温控消融导管经主动脉途径对主动脉瓣上或瓣下（左纤维三角）进行常规标测与消融. 结果 消融成功21例,成功率87.5%,其中2例常规标测未能标测到理想靶点,在EnSite3000-NavX指导下经冠状静脉窦途径采用盐水灌注导管消融成功.21例有效靶点心室电位领先室性期前收缩体表心电图QRS波群起始点（38.04±7.95） ms,放电时间 （214.88±73.68） s.消融失败3例,其中2例在冠状动脉左主干标测到最早心室电位,放弃消融,1例在左冠状动脉窦前下方（距左冠状动脉窦约0.5cm）消融无效.随访（12.9±10.4）个月,复发2例.所有患者无严重并发症. 结论 多数左心室流出道室性期前收缩经主动脉途径采用温控消融导管进行常规标测与消融安全有效,少数患者需经冠状静脉途径采用盐水灌注导管进行标测与消融.     

Initial experience with a novel remote-guided magnetic catheter navigation system for left ventricular scar mapping and ablation in a porcine model of healed myocardial infarction

Objective: This study examined the feasibility of using a remote magnetic catheter navigation system (MNS) in concert with an EAM system to perform detailed left ventricular scar mapping and ablation in a porcine model of healed myocardial infarction.
Background : Substrate-based catheter ablation of ventricular tachycardia (VT) involves detailed electroanatomical mapping (EAM) of the ventricles. While a safe and effective procedure, VT ablation is nonetheless uncommonly performed, due in part to the technical challenges related to ventricular mapping.
Methods: Using a prototype EAM system (CARTO-RMT), seven chronically infarcted swine were mapped using either: (i) a standard manually manipulated catheter or (ii) a magnetic remotely manipulated (Niobe) catheter. A total of 191 ± 54 and 221 ± 64 points were acquired to map the chamber either manually or remotely, respectively.
Results: Procedure times were longer remotely (94 ± 22 vs. 59 ± 19 minute, P = 0.004; and 27 ± 8 vs. 18 ± 3 sec/point, P = 0.04), but this became less apparent with increased operator experience. However, the fluoroscopy time was significantly shorter with remote mapping (56 ± 56 vs. 244 ± 67 sec/map, P = 0.03). The calculated scar size was comparable between the two methods (16.3 ± 4.9 vs. 16.4 ± 4.8 cm², P = 0.37). Pathologic examination confirmed that the MNS was able to precisely deliver radiofrequency lesions to the scar borders. Using the MNS, the error to reach an evenly distributed set of endocardial targets was 6.6 ± 3.6 mm and 4.6 ± 2.0 mm, using transseptal and retrograde approaches, respectively.
Conclusions: Ventricular mapping using this remote navigation paradigm is technically possible and requires minimal fluoroscopy exposure, potentially facilitating ventricular substrate mapping and ablation.     

冠状动脉窦内射频消融治疗频发室性期前收缩和短暂阵发性室性心动过速

目的分析在左冠状动脉窦及无冠状动脉窦内射频消融治疗频发性室性期前收缩和短暂阵发性室性心动过速的心电图特点和射频消融结果。方法对12例室性期前收缩、室性心动过速的病人进行心内电生理标测和射频消融治疗。结果室性期前收缩或室性心动过速均呈左束支传导阻滞图形,胸导联 V3R／S超过1有11例,V2R／S超过1有1例。I导联均为qs波有9例,Ⅱ、Ⅲ、aVF导联均为高大R波, 无切迹,标测确定成功消融靶点在左冠状动脉窦内9例、在无冠状动脉窦内3例,术中无并发症;随访1— 34个月,2例有偶发室性期前收缩。结论在左冠状动脉窦及无冠状动脉窦内射频消融是可行的、安全的。     

起源于主动脉窦内的房性心动过速、频发室性早搏的射频消融治疗

目的报道4例局灶性房性心动过速（房速）,3例频发室性早搏（室早）经主动脉途径在左冠窦和无冠窦内标测和射频消融的结果。方法对4例房速、3例频发室早进行常规心电图、心内电生理检查和射频消融治疗。结果4例阵发性房速患者的标测靶点位于主动脉窦内,在无冠窦成功消融;3例频发室早在左冠窦内标测及消融成功。术中无并发症,随访3～31个月,无1例复发。结论在主动脉无冠窦、左冠窦内射频消融是可行的且能达到安全、有效的治疗目的。尤其适用于在常规、经典部位消融失败的患者。     

Initial Clinical Experience with the New Irrigated Tip Magnetic Catheter for Ablation of Scar-Related Sustained Ventricular Tachycardia: A Small Case Series

Background: A remote magnetic navigation system (MNS) has been used with a nonirrigated magnetic catheter for ablation of some supraventricular and ventricular arrhythmias. However, the irrigated tip catheter has not been evaluated.
Objective: To evaluate the feasibility and efficiency of the newly available irrigated tip magnetic catheter for radiofrequency ablation (RF) of electrical storm due to scar-related ventricular tachycardia (VT) in patients with ischemic heart disease.
Methods: Between January and March 2008, a total of 4 consecutive patients (4 men, mean age 67.7 years) with electrical storm who had an implantable cardioverter defibrillator underwent radiofrequency ablation using a remote MNS and the new magnetic irrigated catheter.
Results: Five ablation procedures were performed in study patients. Acute success, defined as noninducibility of any monomorphic VT, was obtained in 3 patients. In 1 patient, a nonclinical VT remained inducible. A monomorphic VT corresponding to clinical VT with the median (range) cycle length of 485 (440–580) ms was induced in all patients. The duration of ablation was 2,273 (985–3087) seconds, with median total procedure and fluoroscopy times of 135 (100–150) minutes and 6.5 (5–9) minutes, respectively. One recurrence occurred 1 week after ablation, which was ablated successfully in the second session. No complication was observed after ablation. During mean follow-up of 4.2 months, all patients were in sinus rhythm, they received no ICD therapy, and no mortality occurred.
Conclusions: Irrigated ablation of scar-related ventricular tachycardia guided by remote MNS is a feasible and effective modality for management of the electrical storm in patients with ischemic cardiomyopathy with minimal radiation exposure.     

Successful ablition of aortic cusp tachycardia from right ventricle outflow tract using a superior approach

We report a case of successful radiofrequency catheter ablation of idiopathic aortic cusp tachycardia arising close to right coronary artery ostium performed safely from the right ventricular outflow tract (RVOT) by unconventional superior approach. As both activation mapping and pace mapping of the tachycardia were suboptimal from transfemoral RV endocardial approach, retrograde aortic mapping was performed. This revealed that the site of ventricular tachycardia (VT) origin to be on the right coronary sinus. Due to close proximity of VT site of origin and the right coronary ostium, an alternate approach to ablation was considered. We approached this area easily and successfully ablated the VT with an ablation catheter introduced from a right-sided superior approach (jugular vein). The patient has remained free from recurrences over an 18 month follow-up period.     

导管消融治疗起源于主动脉根部附近室性期前收缩7例

目的：分析主动脉根部（AR）附近起源的室性期前收缩（室性早搏,室早）心电图特征和导管消融体会。方法：回顾性分析2010年6月～2012年8月在我院成功行导管射频消融治疗的AR附近起源的7例室早患者资料。结果：7例室早起源于主动脉窦上3例：右冠状动脉窦（RCC）起源1例,左冠状动脉窦（LCC）1例,LCC与RCC交界处1例;主动脉窦下4例：LCC下近RCC1例,主动脉瓣与二尖瓣连接处1例,LCC下左小叶三角1例,二尖瓣环12点1例。所有患者靶点腔内激动标测提示双极靶点电图领先体表心电图QRS波起点20～58（34±12）ms,4例（4／7）靶点部位可见室早时局部电位极性逆转。无消融相关并发症发生。结论：导管消融AR附近起源室早安全、有效,室早体表心电图可初步判断起源部位,标测和消融时注意局部电位特征。     

Tachycardia-Induced Cardiomyopathy Secondary to Right Ventricular Outflow Tract Ventricular Tachycardia: Improvement of Left Ventricular Systolic Function After Radiofrequency Catheter Ablation of the Arrhythmia

Cardiomyopathy Secondary to RVOT VT. Introduction : Several reports describe development of cardiomyopathics secondary to supraventricular tachycardia. Few reports have described cardiomyopathies secondary to ventricular tachycardia.
Methods and Results : We describe a patient who presented with dilated cardiomyopathy and repetitive nonsustained monomorphic ventricular tachycardia. Cardiac cathcterization showed hemodynamically insignificant coronary artery disease. Radiofrequency ablation of a right ventricular outflow tract ventricular tachycardia resulted in improvement of the left ventricular systolic function and resolution of heart failure symptoms.
Conclusions : This report suggests that right ventricular outflow tract ventricular tachycardia may cause reversible tachycardia-induced cardiomyopathy.     

Mapping and Ablation of Frequent Post‐Infarction Premature Ventricular Complexes

Mapping of Post‐Infarction PVCs . Introduction: Premature ventricular complexes (PVCs) occur frequently in patients with heart disease. The sites of origin of PVCs in patients with prior myocardial infarction and the response to catheter ablation have not been systematically assessed. Methods and Results: In 28 consecutive patients (24 men, age 60 ± 10, ejection fraction [EF] 0.37 ± 0.14) with remote myocardial infarction referred for catheter ablation of symptomatic refractory PVCs, the PVCs were mapped by activation mapping or pace mapping using an irrigated‐tip catheter in conjunction with an electroanatomic mapping system. The site of origin (SOO) was classified as being within low‐voltage (scar) tissue (amplitude ≤1.5 mV) or tissue with preserved voltage (>1.5 mV). The SOO was confined to endocardial scar tissue in 24/28 patients (86%). The SOO was outside of scar in 3 patients and could not be identified in 1 patient. At the SOO, local endocardial activation preceded the PVC by 46 ± 19 ms, and the electrogram amplitude during sinus rhythm was 0.48 ± 0.34 mV. The PVCs were effectively ablated in 25/28 patients (89%), resulting in a decrease in PVC burden on a 24‐hour Holter monitor from 15.6 ± 12.3% to 2.4 ± 4.2% (P < 0.001). The SOO most often was confined to scar tissue located in the left ventricular septum and the papillary muscles. Conclusion: Similar to post‐infarction ventricular tachycardia, PVCs after remote myocardial infarction most often originate within scar tissue. Catheter ablation of these PVCs has a high‐success rate. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1002‐1008, September 2010)     

Retrograde Coronary Venous Infusion of Ethanol for Ablation of Canine Ventricular Myocardium

Retrograde Coronary Venous Ethanol Infusion for Ablation. Introduction : Permanent cure of reentrant ventricular tachycardia (VT) associated with coronary artery disease is difficult to achieve. Retrograde coronary venous infusion of ethanol for ablation of ventricular myocardium associated with reentrant tachyarrhythmias has several potential advantages, including use of physiologic mapping techniques and production of deeper, wider necrotic zones.
Methods and Results: Nine anesthetized dogs had baseline hemodynamic measurement, left ventriculography, coronary arteriography, occlusive coronary venography, and programmed electrical stimulation of the right ventricular apex and outflow tract. A balloon-tipped infusion catheter was advanced into a distal coronary venous branch, the balloon slowly inflated, and pure ethanol infused at volumes of 1.5, 3, or 5 cc. Hemodynamic measurements, angiography, ventriculography, and programmed electrical stimulation were repeated immediately and 1 week following ablation. Formalin-perfused hearts were serially sectioned and lesion volumes determined. Histologic examination of ablation beds then was performed. No significant difference was found in any hemodynamic measurement before or after ablation. Coronary arteriograms and left ventriculograms were unchanged after ablation. Nonsustained VT occurred in eight dogs during ethanol infusion; however, VT was not inducible in any dog before or after ablation. Infusion volumes of 3 cc or more were required to produce transmural lesions.
Conclusion : Retrograde coronary venous infusions of ethanol using a balloon-tipped infusion catheter were effective in ablating ventricular myocardium. Retrograde chemical ablation did not itself result in inducible VT or adversely affect hemodynamic measurements or coronary arteries. Transmural myocardial necrosis, necessary in the ablation of VT associated with coronary artery disease, can be produced by higher infusion volumes.