Ventricular tachycardia in the era of ventricular assist devices

Sustained ventricular tachycardia (VT) in patients with advanced cardiomyopathy is a potentially life-threatening arrhythmia. Newer treatment strategies have evolved that combine the use of catheter ablation to target the substrate for VT and ventricular assist devices (VADs) to hemodynamically support the failing ventricle. This editorial is targeted to the practicing clinician caring for these difficult patients. The current article reviews the use of percutaneous VADs to support catheter ablation of VT, the use of durable VADs to support the failing heart in patients with recurrent VT, ventricular arrhythmias in patients with durable VADs, and the use of catheter ablation to treat VT in patients with durable VADs.     

His-Purkinje system re-entry in patients with clustering ventricular tachycardia episodes

Aims: Multiple arrhythmia re-inductions were recently shown in His-Purkinjesystem (HPS) ventricular tachycardia (VT). We hypothesized thatHPS VT was a frequent mechanism of repetitive or incessant VTand assessed diagnostic criteria to select patients likely tohave HPS VT. Methods and results: Consecutive patients with clustering VT episodes (>3 sustainedmonomorphic VT within 2 weeks) were included in the analysis.HPS VT was considered plausible in patients with (i) impairedleft ventricular function associated with dilated cardiomyopathyor valvular heart disease; or (ii) ECG during VT similar tosinus rhythm QRS or to bundle-branch block QRS. HPS VT was plausiblein 12 of 48 patients and HPS VT was demonstrated in 6 of 12patients (50%, or 13% of the whole study group). Median VT cyclelength was 318 ms (250–550). Catheter ablation was successfulin all six patients. Conclusion: His-Purkinje system VT is found in a significant number of patientswith repetitive or incessant VT episodes, and in a large proportionof patients with predefined clinical or electrocardiographiccharacteristics. Since it is easily amenable to catheter ablation,our data support the screening of all patients with repetitiveVT in this regard and an invasive approach in a selected groupof patients.     

Significance of catheter ablation as emergency intervention in patients with sustained monomorphic ventricular tachycardia]

Treatment of incessant ventricular tachycardia (VT) refractory to antiarrhythmic drugs and DC cardioversion is difficult and still debated. We performed catheter ablation (CA) of sustained monomorphic ventricular tachycardias (VT) with high-energy DC shock (360-400 Joule) in 11 patients (pts) with incessant VT (duration greater than 24 h), refractory to antiarrhythmic drugs and DC cardioversion. Ten pts suffered from coronary disease and one pt from dilated cardiomyopathy. DC energy was delivered either at the site of the earliest endocardial activation (EEA) (six pts) or at the area of slow conduction (ASC) (five pts). In nine pts incessant VT could be terminated by DC ablation; two pts had to undergo emergency endocardial resection. During the mean follow-up of 31 +/- 26 (1-66) months nonfatal VT recurrences occurred in five pts with CA at the EEA and in one pt with CA at the ASC. We conclude that CA of incessant VT is an effective approach to terminate VT. However, there is a high incidence of nonfatal recurrence after CA, particularly when DC energy is delivered at the earliest site of endocardial activation.     

Nonsurgical transthoracic epicardial radiofrequency ablation: an alternative in incessant ventricular tachycardia

OBJECTIVES: The purpose of this study was to analyze the feasibility, efficacy, and safety of epicardial radiofrequency (RF) ablation in patients with incessant ventricular tachycardia (VT). BACKGROUND: Management of patients with incessant VT is a difficult clinical problem. Drugs and RF catheter ablation are not always effective. A nonsurgical transthoracic epicardial RF ablation can be an alternative in patients refractory to conventional therapy. METHODS: Epicardial RF ablation was performed in 10 patients who presented with incessant VT despite the use of two or more intravenous antiarrhythmic drugs. RESULTS: In eight patients, endocardial ablation (EdA) failed to control the tachycardia. In the remaining two patients, epicardial ablation (EpA) was first attempted because of left ventricular thrombus and severe artery disease, respectively. Eight patients had a diagnosis of coronary artery disease with healed myocardial infarction. One patient had dilated cardiomyopathy, and one patient had idiopathic, incessant VT. In patients with structural heart disease, the mean ejection fraction was 0.28 +/- 0.10%. Four patients previously received an implantable defibrillator. The EpA effectively terminated the incessant tachycardia in eight patients, which represents a success rate of 80%. In them, after a follow-up of 18 +/- 18 months, a single episode of a different VT was documented in one patient. No significant complications occurred related to the procedure. CONCLUSIONS: In patients with incessant VT despite the use of drugs or standard EdA, the epicardial approach was very effective and should be considered as an alternative in this life-threatening situation.     

Ablation of incessant ventricular tachycardia with the use of epicardial approach in a patient after CABG - a case report

Percutaneous epicardial catheter ablation of ventricular tachycardia (VT) is used when ablation by a conventional endocardial access has been unsuccessful. In patients after cardiac surgery operations, due to high risk, an open chest approach for ablation is usually used. We report a case of 66 year-old man after bypass surgery operation admitted to the hospital with incessant VT, which was successfully ablated from the epicardial aspect achieved by subxyphoidal approach.     

Ablación de taquicardia ventricular asistida con ECMO. Primera experiencia en nuestra institución

Catheter ablation is useful for reducing drug refractory ventricular tachycardia (VT) episodes and can be life-saving when VT is incessant or arrhythmic storm. Left ventricular hemodynamic support may be required in patients with VT and hemodynamic instability. Extracorporeal membrane oxygenation (ECMO) support is an alternative to achieve ventricular tachycardia mapping and ablation over long periods of time. We present a case of successful catheter ablation of substrate in a patient with ischemic heart disease and ventricular tachycardia with hemodynamic instability performed using venous- arterial ECMO support. There were not episodes of ventricular tachycardia after 2 years of follow-up.     

Successful radiofrequency catheter ablation of incessant ventricular tachycardia with a delta wave-like beginning of the QRS complex

Ventricular tachycardia with a delta wave-like beginning of the QRS complex is considered to be refractory to endocardial catheter ablation because it originates from the epicardial region. A 45-year-old woman had incessant ventricular tachycardia with a delta wave-like beginning of the QRS complex which was resistant to several antiarrhythmic drugs. The origin of the arrhythmia was at the mitral annulus on the antero-lateral left ventricular wall. The earliest endocardial activation preceded the QRS complex by 18 msec. After 7 sec of endocardial radiofrequency application ventricular tachycardia was terminated. During a 2 year follow-up ventricular tachycardia did not recur and only small numbers of premature ventricular contractions (< 100/day) were noted. VT with delta wave-like QRS morphology which originates from the basal region of the ventricle may be treated successfully with radiofrequency catheter ablation using an endocardial approach.     

Use of a closed loop irrigated catheter in epicardial ablation of ventricular tachycardia

Purpose

Catheter ablation of ventricular tachycardia (VT) often requires a combined epicardial and endocardial approach. An open irrigated catheter for epicardial ablation of ventricular tachycardia is commonly used. However, this can be associated with problems of fluid accumulation in the pericardial space necessitating repeated aspirations and interfering with catheter–tissue contact. A closed loop irrigated catheter can be a viable alternative to overcome these problems. We report our first three cases of epicardial VT ablation using a closed loop irrigated ablation catheter (Chilli II, Boston Scientific).

Methods

Catheter ablation of ventricular tachycardia was performed via epicardial and endocardial approaches using a closed loop irrigated ablation catheter (Chilli II, Boston Scientific) and using 3-D mapping with EnSite/NavX system. Patients were routinely followed up after the catheter ablation procedure in clinic for any recurrence of ventricular arrhythmia.

Results

We report our first three cases of epicardial VT ablation using a closed loop irrigated ablation catheter. Power delivery was adequate with mean power of 15.2?±?2.8, 31.1?±?3.8, and 25.0?±?3.3 W, respectively, in the three patients. No impedance rises were noted during the lesion formation. There was no recurrence of VT in any of the patients after 3 months of follow-up.

Conclusions

To our knowledge, we report the first case series of epicardial VT ablation using a closed loop irrigated catheter and the EnSite/NavX mapping system. The advantages of closed irrigation, especially in conjunction with impedance-based anatomical mapping, warrant further study of its efficacy in catheter ablation from the pericardial space.     

Nonsurgical transthoracic epicardial catheter ablation to treat recurrent ventricular tachycardia occurring late after myocardial infarction

OBJECTIVES: We sought to evaluate feasibility, safety and results of transthoracic epicardial catheter ablation in patients with ventricular tachycardia occurring late after an inferior wall myocardial infarction. BACKGROUND: Transthoracic epicardial catheter ablation effectively controls recurrent ventricular tachycardia (VT) in patients with Chagas' disease in whom epicardial circuits predominate. Epicardial circuits also occur in postinfarction VT. METHODS: Fourteen consecutive patients aged 53.6 +/- 14.5 years with postinfarction VT related to the inferior wall were studied. The VT cycle length was 412 +/- 51 ms. Two patients had previously undergone unsuccessful standard endocardial radiofrequency energy (RF) ablation. The VT was incessant in one patient. Left ventricular angiography showed inferior akinesia in 13 patients and an inferior aneurysm in 1 patient. Ablation was performed with a regular steerable catheter placed into the pericardial sac by pericardial puncture. RESULTS: The pericardial space was reached in all patients. Electrophysiologic evidence of an epicardial circuit was present in 7 of 30 VTs. Due to a high stimulation threshold, empirical thermal mapping was the only criterion used to select the site for ablation. Three VTs were interrupted during the first RF pulse. Two pulses were necessary to render it noninducible in 3 patients (1 VT per patient). In the remaining 4 VTs, 3, 3, 4 and 5 RF pulses, respectively, were used. The overall success was 37.14% (95% confidence interval, 11.83% to 62.45%). Patients are asymptomatic for 14 +/- 2 months. CONCLUSIONS: Postinfarction pericardial adherence does not preclude epicardial mapping and ablation to control VT related to an epicardial circuit in postinferior wall myocardial infarction.     

三维标测指导致心律失常性右心室心肌病室性心动过速的射频消融

目的介绍致心律失常性右心室心肌病（ARVC）室性心动过速（室速）的三维标测方法及其消融策略。方法21例ARVC室速患者,因1—4种抗心律失常药物治疗无效,临床上呈反复发作、无休止发作或植入型心律转复除颤器（ICD）植入后频繁放电治疗,接受导管消融治疗。其中,男性19例,女性2例,平均年龄（32±12）岁。9例患者接受电解剖（Carto）标测,12例患者接受非接触标测（EnSite—Array）。在首先明确病变基质的基础上,通过激动标测、拖带标测及起搏标测,分析心动过速的起源、可能的传导径路及其出口以及它们与病变基质的关系。通常于心动过速的出口处及其周边行局灶消融,术中病变基质周边的延迟激动电位应一并消融。结果21例患者,2例呈无休止发作,1例患者表现为频繁室性早搏及加速性室性自主心律,余18例患者消融中共诱发出34种心动过速。所有心动过速均呈左束支阻滞形,平均心动过速周长为（289±68）ms。16例患者（28种室速）消融治疗即刻成功,3例患者（7种室速）部分成功,2例患者（2种室速）消融失败,即刻消融成功率76．2％。所有患者消融术后继续服用抗心律失常药物。平均随访6～30（1d±7）个月,成功患者中2例复发,其中1例再次消融成功;未达即刻成功的5例患者,经抗心律失常药物治疗后,均无室性心律失常事件发生,其中包括1例消融后植入ICD者。结论三维标测系统可首先明确ARVC患者的病变基质,在此基础上结合激动标测和心内各种电刺激技术,可直观显示心动过速的起源、缓慢传导区出口及折返环路,以此制定消融策略可成功治疗ARVC室速。心动过速起源于心肌深部或ARVC病变进展,是消融失败和复发的常见原因。     

Transcoronary ethanol ventricular tachycardia ablation in the modern electrophysiology era.

BACKGROUND: Radiofrequency catheter ablation for ventricular tachycardia (VT) may be unsuccessful when critical portions of the circuit cannot be interrupted with either endocardial or epicardial radiofrequency application. OBJECTIVE: We sought to investigate whether transcoronary ethanol ablation (TCEA) can be used as a therapy for patients with VT who have failed medications and radiofrequency ablation in the modern era. METHODS: Nine patients (7 men, 55 +/- 9 years old, left ventricular ejection fraction 23% +/- 8%, 2.2 +/- 0.8 failed VT ablations) with at least 1 unsuccessful attempt at radiofrequency catheter ablation for symptomatic VT at our institution between 2000 and May 2007 underwent TCEA. The majority of patients had an ischemic cardiomyopathy (67%), and all patients had VT due to scar-related reentry. In the 7 patients with VT involving a septal scar, a septal perforator artery was a suitable target in 5 patients, whereas in the remaining patients, a distal branch of the circumflex and the conus branch of the right coronary artery were targeted. In the 2 patients in whom VT involved an inferior scar, a branch of the posterior descending artery was targeted. RESULTS: Acute success was obtained in 56% of patients (89% for clinical targeted VT). During a mean follow-up of 29 +/- 23 months, 3 deaths occurred and 67% of the patients were free of recurrence. CONCLUSION: TCEA may represent an option in patients with refractory VT in whom radiofrequency ablation fails, especially in cases of septal scar in which failure is thought to be caused by inability to provide adequate lesion depth.     

Value of high-density endocardial and epicardial mapping for catheter ablation of hemodynamically unstable ventricular tachycardia

BACKGROUND: Percutaneous epicardial mapping has been used for ablation of recurrent ventricular tachycardia (VT). OBJECTIVES: The purpose of this study was to use a combined epicardial and endocardial mapping strategy to delineate the myocardial substrate for recurrent VT in both ischemic (n = 12) and nonischemic cardiomyopathy (n = 8), and to define the role of epicardial ablation. METHODS: Electroanatomic mapping was performed in 20 patients. High-density voltage maps were obtained by acquiring both endocardial and epicardial electrograms. Electrograms derived from six patients with structurally normal hearts were used as controls. A total of 26 VTs were targeted in the 20 patients. RESULTS: Most VTs (23/26 [88.5%]) were hemodynamically unstable. In patients with ischemic cardiomyopathy, the extent of endocardial scar was greater than epicardial scar. A definable pattern of scar could not be demonstrated in nonischemic cardiomyopathy. Pathologic examination of explanted hearts in two patients with nonischemic cardiomyopathy demonstrated that low-voltage areas were not always predictive of scarred myocardium. A substrate-based approach was used for catheter ablation. Catheter ablation was performed on the endocardium in all patients; additional epicardial delivery of radiofrequency energy was required in 8 (40%) of 20 patients for successful ablation. During follow-up (12 +/- 4 months), 15 (75%) of 20 patients have been arrhythmia-free. CONCLUSION: Patients with ischemic cardiomyopathy tend to have a larger endocardial than epicardial scar. Use of epicardial and endocardial electroanatomic mapping to define the full extent of myocardial scars allows successful catheter ablation in patients with hemodynamically unstable VTs.     

特发性束支折返性室性心动过速的临床特点(附二例报道)

通过对两例特发性束支折返性室性心动过速 (BBR VT)的临床、心电图及电生理特性进行分析 ,提出该类病人的临床特点。两例病人均无器质性心脏病的证据。例 1男性 ,VT发作最长持续达 2 7h ,体表心电图呈近似心室扑动的图形 ,心内电生理检查证实为类左束支阻滞图形 ,QRS波宽 2 6 0ms。平时体表心电图QRS波正常 ,心内电图提示HV间期延长 ,VT可稳定诱发和终止 ,存在V3 现象 ,右束支消融成功。例 2女性 ,VT发作病史 7年 ,呈无休止性VT发作 ,平时体表心电图为完全性右束支传导阻滞伴左前分支阻滞图形 ,VT可稳定诱发和终止 ,发作时其QRS波宽为 14 0ms ,呈类完全性右束支传导阻滞伴左前分支阻滞图形 ,V波前有稳定的H波 ,消融左后分支后可导致Ⅲ度房室阻滞而终止VT。结论 :束支折返性VT可见于无器质性心脏病病人 ,有独特的电生理特性 ;是一种特殊类型的特发性VT     

Nonsurgical transthoracic mapping and ablation in a child with incessant ventricular tachycardia

We report the case of an 11-month-old child with incessant ventricular tachycardia who underwent two unsuccessful endocardial ablations with standard catheters and in whom the ventricular tachycardia was interrupted only during transthoracic epicardial catheter ablation. This report outlines the usefulness and safety of this novel approach in pediatric patients before surgery when endocardial ablation fails.     

Catheter ablation of electrical storm in a patient with left ventricular assist device

Catheter ablation is an effective treatment for ventricular tachycardia (VT) in structural heart disease to reduce VT recurrence and implantable cardioverter defibrillator shocks.Current guidelines recommend ablation in patients with recurrent or incessant VT. In patients with left ventricular assist device (LVAD), VTs may be well tolerated hemodynamically and catheter ablation has been performed rarely, until now. We present a case of successful VT ablation in a patient with LVAD and electrical storm. Effective ablation after a transseptal LV access was achieved using electroanatomic mapping and a substrate-based approach. On the basis of this case, we discuss the pros and cons of VT ablation in these patients.     

Percutaneous epicardial ablation reverses ventricular tachycardia mediated cardiomyopathy

We report on the case of an 18-year-old girl with asymptomatic incessant ventricular tachycardia. Initial attempts at endocardial ablation failed and she was monitored until her cardiac function deteriorated. A percutaneous epicardial approach with electroanatomical mapping was then used which successfully terminated the tachycardia. Left ventricular size and function subsequently returned to normal. This case demonstrates that percutaneous epicardial ablation of ventricular tachycardia is safe and feasible in young patients and highlights the importance of recognising this at an early stage.     

Radiofrequency catheter ablation of idiopathic left ventricular outflow tract tachycardia: utility of intracardiac echocardiography

INTRODUCTION: The site of origin of idiopathic ventricular tachycardia (VT) arising from the left ventricular outflow tract (LVOT) may be closely related to the aortic valve leaflets, and radiofrequency (RF) delivery potentially can damage them. Intracardiac echocardiography (ICE) can identify accurately the ablation electrode and anatomic landmarks, and contact with the endocardium can be easily assessed. The aim of this study was to define the utility and the accuracy of ICE in guiding RF ablation of idiopathic VT of the LVOT. METHODS AND RESULTS: Five consecutive patients (all men; mean age 20.4 years, range 16 to 25) symptomatic for idiopathic VT underwent RF ablation. A 9-French, in-sheath catheter with a 9-MHz ultrasound transducer was inserted through the femoral vein and positioned in the His-bundle region or right ventricular outflow tract to provide a clear view of the aortic root. Local earliest ventricular activation during tachycardia and pace mapping were used to identify the ablation site. Idiopathic VT was ablated successfully in all patients using a median of two RF pulses, delivered during tachycardia. High-resolution images of the aortic valve and ablation electrode were achievable in all cases. Direct vision of ablation electrode-endocardial contact in the outflow tract was assessed easily in all patients. CONCLUSION: Idiopathic VT of the LVOT can be treated successfully with RF ablation. ICE can accurately guide catheter ablation and identify anatomic landmarks, endocardial contact, and ablation electrode movement.     

Mechanical interruption of postinfarction ventricular tachycardia as a guide for catheter ablation

BACKGROUND: Mechanical trauma has been described as a helpful guide for ablation of atrial tachycardias and accessory pathways. In postinfarction ventricular tachycardia (VT), the reentrant circuit is partly endocardial and therefore may be susceptible to catheter trauma. OBJECTIVES: The purpose of this study was to determine the prevalence and significance of VT termination resulting from catheter trauma. METHODS: A consecutive series of 39 patients (mean age 68 +/- 7 years, ejection fraction 0.25 +/- 0.02) underwent left ventricular mapping for postinfarction VT. Mapping was performed during 62 hemodynamically tolerated VTs (mean cycle length 451 +/- 88 ms). Only hemodynamically tolerated VTs that did not terminate spontaneously and VTs that were reproducibly inducible were included in the study. VT termination was considered mechanical only if it was not caused by a premature depolarization. RESULTS: In 13 of 62 VTs (21%) in 8 of 39 patients (21%), either VT terminated during catheter placement at a particular site (n = 7) or a previously reproducibly inducible VT became no longer inducible with the mapping catheter located at a particular site (n = 6). The stimulus-QRS interval was significantly shorter at sites where mechanical trauma affected the reentrant circuit compared with sites having concealed entrainment (102 +/- 56 ms vs 253 +/- 134 ms, P = .003). At the site that was susceptible to mechanical trauma, the pace map was identical or highly similar in 13 of 13 VTs. After radiofrequency ablation at these sites, the targeted VTs were no longer inducible. No patient had recurrence of the targeted VT during a mean follow-up of 15 +/- 11 months. CONCLUSIONS: Catheter contact at a critical endocardial site can interrupt postinfarction VT or prevent its induction. Radiofrequency ablation at sites of mechanical termination of VT has a high probability of success.     

射频消融特发性室性心动过速的标测方法初探（附五例分析）

５例特发性室性心动过速（ＶＴ）经射频电流导管消融（ＲＦＣＡ）而获治愈。本文从成功的ＲＦＣＡ结果着重探讨特发性ＶＴ兴奋灶的标测方法。心内膜激动时间标测，以局部电图较体表导联ＱＲＳ波时间提前≥１０ｍｓ处定为心室最早激动点（ＥＶＡ），５例平均心室最早激动至ＱＲＳ波起始时间为１８±１１．７ｍｓ，在ＥＶＡ处放电消融仅１例成功。采用起搏标测法定位以略低于自发ＶＴ的频率沿ＥＶＡ上下左右逐点标测，寻找起搏电图至少１１个导联的ＱＲＳ波形态、振幅、极性与自发ＶＴ相同的标测点放电消融，４例均获成功。消融成功的局部电图较ＱＲＳ波平均提前２６±１２．８ｍｓ。结果提示联合应用心内膜激动时间标测和起搏标测并侧重于后者，可能是提高ＲＦＣＡ特发性ＶＴ成功率的一种有效方法。     

Mapping and ablation of ventricular tachycardia guided by virtual electrograms using a noncontact, computerized mapping system

OBJECTIVES: The purpose of this study was to describe a computerized mapping system that utilizes a noncontact, 64 electrode balloon catheter to compute virtual electrograms simultaneously at 3,360 left ventricular (LV) sites and to assess the clinical utility of this system for mapping and ablating ventricular tachycardia (VT). BACKGROUND: Mapping VT in the electrophysiology laboratory conventionally is achieved by sequentially positioning an electrode catheter at multiple endocardial sites. METHODS: Fifteen patients with VT underwent 18 electrophysiology procedures using the noncontact, computerized mapping system. A 9F 64 electrode balloon catheter and a conventional 7F electrode catheter for mapping and ablation were positioned in the LV using a retrograde aortic approach. Using a boundary element inverse solution, 3,360 virtual endocardial electrograms were computed and used to derive isopotential maps. An incorporated locator system was used in conjunction with or instead of fluoroscopy to position the conventional electrode catheter. RESULTS: A total of 21 VTs, 12 of which were hemodynamically-tolerated and 9 of which were not, were mapped. Isolated diastolic potentials, presystolic areas, zones of slow conduction and exit sites during VT were identified using virtual electrograms and isopotential maps. Among 19 targeted VTs, radiofrequency ablation guided by the computerized mapping system and the locator signal was successful in 15. CONCLUSIONS: The computerized mapping system described in this study computes accurate isopotential maps that are a useful guide for ablation of hemodynamically stable or unstable VT.