Ventricular tachycardia late after repair of congenital heart disease: efficacy of combination therapy with radiofrequency catheter ablation and class III antiarrhythmic agents and long-term outcome

OBJECTIVE: This study investigated the treatment of ventricular tachycardia (VT) after repair of tetralogy of Fallot or double outlet of the right ventricle. BACKGROUND: The ideal antiarrhythmic therapy for VT in patients after repair of congenital heart disease, especially without left ventricular dysfunction, has not yet been established. METHODS: Seven consecutive patients (2 women and 5 men) with stable monomorphic sustained VT were investigated. The mean age was 25 +/- 7 years (range, 16-35 years). Four patients had undergone surgical repair of tetralogy of Fallot, and 3 had surgical correction of double outlet of the right ventricle at the mean age of 18 +/- 7 years (range, 9-27 years) before documentation of the arrhythmia. RESULTS: The mean ejection fraction of the left ventricle was 60% +/- 8% (range, 50-72). Fourteen sustained monomorphic VTs were induced in 7 patients using programmed electrical stimulation. The mean cycle length of tachycardia was 346 +/- 77 milliseconds (range, 260-480 seconds). The site of the surgical correction of the right ventricle was associated with the origin of VT in all patients. Radiofrequency catheter ablation was attempted in 8 VTs in 7 patients: 7 clinical and 1 nonclinical VTs. In 6 patients, class III antarrhythmic agents were added because VT remained inducible after ablation. During a follow-up of 61 +/- 29 months (range, 15-110 months), there were no recurrences of VT. CONCLUSION: In patients with drug-refractory VT originating from the right ventricle late after congenital heart disease, and when their left ventricular function do not deteriorate, combined therapy for radiofrequency catheter ablation with class III antiarrhythmic agents might effective and should be considered as a therapeutic option.     

Unidirectional conduction block at cavotricuspid isthmus created by radiofrequency catheter ablation in patients with typical atrial flutter

INTRODUCTION: Although unidirectional conduction block at the cavotricuspid isthmus can be created by radiofrequency ablation for atrial flutter, its underlying mechanism has not been elucidated. METHODS AND RESULTS: Twenty-seven patients (22 men and 5 women; mean age 59 +/- 11 years) who met the following criteria were studied: (1) bidirectional isthmus conduction demonstrable at baseline; (2) at least one linear lesion attempted on the cavotricuspid isthmus with radiofrequency catheter ablation; and (3) conduction times at anterolateral and posteromedial portions of the isthmus measured for both clockwise and counterclockwise directions before the ablation procedure. Unidirectional conduction block was observed before achieving bidirectional block in 9 patients (group I); the remaining 18 patients did not exhibit unidirectional conduction block (group II). All unidirectional conduction blocks were demonstrated in the counterclockwise direction. Anterolateral isthmus conduction time in group I was significantly longer than that in group II in both directions. However, there were no significant differences in posteromedial isthmus conduction time between groups I and II in either direction. Anterolateral isthmus conduction time was significantly longer than posteromedial conduction time in group I but not in group II. CONCLUSION: There were significant differences in conduction properties at the cavotricuspid isthmus between patients who developed unidirectional conduction block and those who did not. Our results support the notion that anisotropy contributes to the genesis of unidirectional conduction block at the cavotricuspid isthmus during the radiofrequency ablation procedure.     

Radiofrequenz-Katheterablation von Vorhofflattern und Vorhofflimmern

Radiofrequency catheter ablation is now considered as a curative approach in patients with typical atrial flutter. Typical atrial flutter is due to a macrore-entrant circuit within the right atrium and it can be eliminated by a linear lesion in the isthmus between the tricuspid annulus and the vena cava inferior. The electrophysiological criterion of a bidirectional isthmus block has been shown to reduce the recurrence rate of atrial flutter after catheter ablation, thus achieving long-term cure of typical atrial flutter. Acute success rates of 85 to 90% and recurrence rates of 10 to 15% have been reported. The risk of paroxysmal atrial fibrillation continues to be clinically relevant in patients who underwent successful ablation of atrial flutter, in particular in patients with previously documented atrial fibrillation. The incidence of a new onset of atrial fibrillation after ablation of atrial flutter seems to be approximately 20%. Isthmus ablation has also been shown to be beneficial for the majority of patients with typical atrial flutter and atrial fibrillation: In addition to an elimination of typical atrial flutter the isthmus ablation apparently reduces the incidence of paroxysmal atrial fibrillation. At present, atrial fibrillation can only be treated by catheter ablation as a curative approach in the rare cases where an accessory pathway, an AV nodal re-entrant tachycardia, typical atrial flutter or an ectopic atrial tachycardia is the induction mechanism of the atrial fibrillation. The majority of patients with atrial fibrillation is apparently not amenable to a curative local ablation. While AV junction ablation and AV node modification can palliate some of the symptoms of atrial fibrillation by a control of ventricular rate, the arrhythmia persists with the loss of AV synchrony and continued risk of thromboembolism. The surgical MAZE procedure implies a compartimentation of the atria by surgical incisions resulting in areas to small to sustain the arrhythmia. Based on this procedure experimental and clinical studies are currently performed in order to develop catheter ablation cure of atrial fibrillation.     

Necessity for biatrial ablation to achieve bidirectional cavotricuspid isthmus conduction block in a patient following senning operation

We report the case of a 28-year-old male patient with a 17-year history of recurrent symptomatic atrial tachyarrhythmia following Senning operation for transposition of the great arteries. Biatrial electroanatomic mapping and entrainment mapping revealed counterclockwise peri-tricuspid annulus reentry in which cavotricuspid isthmus tissue in both systemic and pulmonary venous atria was involved. Linear ablation of the cavotricuspid isthmus in the pulmonary venous atrium terminated the tachycardia but did not block the isthmus conduction, and the tachycardia was reinduced. Bidirectional isthmus conduction block could be achieved only after additional linear ablation targeting the cavotricuspid isthmus tissue in the systemic venous atrium. We conclude that biatrial ablation may be necessary in order to achieve bidirectional isthmus block and prevent tachycardia recurrence in some patients following Senning or Mustard operation.     

Ablation of Ventricular Tachycardia Due to a Postinfarct Ventricular Septal Defect:

Outer Loop Tachycardia. Introduction : Ventricular tachycardia (VT) alter postinfarct ventricular septal defect (VSD) repair has not been well characterized.
Methods and Results: A 55-year-old man developed refractory VT after inferior wall infarction and VSD repair. Entrainment demonstrated a broad reentry circuit path (outer loop) between the tricuspid annulus and VSD patch. A series of radiofrequency (RF) lesions transected this path, abolishing VI' and producing conduction block between the inferior and superior aspects of the basal right ventricular septum.
Conclusion: Some VTs have broad reentry loops requiring ablation by a series of RF lesions across the path to create a line of block. This approach is analogous to that for atrial flutter.     

单导管标测在心房扑动射频消融中的意义

目的:探讨单导管标测法在心房扑动(房扑)射频消融中的应用方法和效果。方法:阵发性心房颤动并发房扑患者行肺静脉电隔离术时采用单导管标测法消融房扑30例。所有患者行肺静脉电隔离术后,将10极冠状静脉窦(CS)导管远端2对电极放置于CS内,余位于CS外,并使之有一定的张力,使导管贴靠于三尖瓣环和低右房。用冷盐水灌注消融导管线性消融三尖瓣峡部,房扑发作患者在房扑下消融,窦律患者在CS远端电极起搏下消融,可在术中随时把大头消融导管置于希氏束部位,用于评价是否已完全达双向阻滞,即:起搏CS远端电极,刺激信号至CS近端电极A波的距离大于至希氏束A波的距离,则CS口至低右房单向阻滞;CS近端电极起搏,刺激信号至CS远端电极A波的距离大于至希氏束A波的距离,则低右房至CS口单向阻滞,从而达双向阻滞,CS近端电极起搏所需电压较高,有的患者可达24mA。结果:所用阵发性心房颤动并发房扑患者均成功行三尖瓣峡部线性射频消融,达到双向阻滞,无手术相关并发症,随访4个月～2年,无房扑复发。结论:单导管标测法对房扑患者行三尖瓣峡部线性射频消融操作简单、快速,可完全用于评价消融结果,成功率高,并且节省手术费用。     

Disorders of the rhythm and conduction in patients operated on for a total correction of tetralogy of Fallot

The purpose of this paper is to analyze the incidence of arrhythmias and conduction disturbances in 81 patients after total surgical repair of tetralogy of Fallot. The study was done at the National Institute of Cardiology "Ignacio Chávez" from 1974 to 1989. Sixty five patients (78.9%) developed a pattern of right bundle block and ten patients (12.3%) had additional left anterior hemiblock following surgery. Two patients had complete heart block so pacemaker was implanted. The incidence of serious ventricular arrhythmias was found in 11 patients often polymorphic ventricular premature complexes. One case sustained monomorphic ventricular tachycardia. Electrophysiological study demonstrated that it source was the scar of the right ventricle outflow tract. This tachycardia is now under control with specific antiarrhythmic therapy.     

Tachycardias of right ventricular origin.

Ventricular tachycardia arising from the right ventricle usually has a left bundle branch morphology and occurs in a variety of disorders. Uhl's anomaly and right ventricular dysplasia may represent a spectrum of one disorder and are a cause of right heart dilatation, failure, and premature sudden death due to ventricular arrhythmias. Familial forms of the disorder may account for focal clustering in some geographic areas. Management should involve aggressive stratification of arrhythmia risk and may include medical, surgical, or device therapy. In contrast, the syndrome of right ventricular outflow tract tachycardia, including nonischemic exercise-induced and repetitive monomorphic ventricular tachycardia, is a more benign entity. Management often involves beta- and calcium channel blocking drugs or type IC antiarrhythmic drugs. Catheter ablation of the arrhythmia focus in the right ventricular outflow tract has been used in selected patients. In this syndrome the right ventricle is normal, and noninvasive testing as well as electrophysiologic studies can be helpful in distinguishing it from the more malignant right ventricular dysplasia. Ventricular arrhythmias may also be seen after right ventricular incision, as in surgical repair of tetralogy of Fallot and ventricular septal defects. Significant ventricular ectopy associated with an abnormal right ventricle (enlarged or depressed systolic function) is associated with an increased risk for sustained arrhythmia and sudden cardiac death in this group. The optimal indicator(s) of highest risk in these patients remains under investigation but will likely include electrophysiologic testing. Bifascicular block occurs commonly after repair of tetralogy of Fallot, but is usually benign. Isolated right ventricular infarction is rare. Most right ventricular arrhythmias associated with ischemia occur in the setting of iatrogenic catheter manipulation for pacing or hemodynamic monitoring. In conclusion, right ventricular arrhythmias involve an unusual and interesting group of clinical entities and appear to span the spectrum of arrhythmias mechanisms. A macroreentrant activation ring around the ventriculotomy scar may account for the arrhythmias following repair of tetralogy of Fallot. Microreentry at sites of morphologic abnormalities results in the arrhythmias associated with right ventricular dysplasia and ischemia. Triggered activity related to DADs or, less likely, abnormal automaticity, produce repetitive monomorphic ventricular tachycardia and nonischemic exercise-induced ventricular tachycardia, both of which usually originate from the right ventricular outflow tract. Iatrogenic ventricular tachycardia associated with catheter manipulation is especially likely to occur in the presence of right ventricular ischemia and infarction. It is important to recognize these clinical entities because treatment is specific.(ABSTRACT TRUNCATED AT 400 WORDS)     

Radiofrequency ablation for cure of atrial flutter

Abstract Background: Atrial flutter is a common arrhythmia which frequently recurs after cardioversion and is relatively difficult to control with antiarrhythmic agents.
Aims: To evaluate the success rate, recurrence rate and safety of radiofrequency (RF) ablation for atrial flutter in a consecutive series of patients with drug refractory chronic or paroxysmal forms of the arrhythmia.
Methods: Electrophysiologic evaluation of atrial flutter included activation mapping with a 20 electrode halo cadieter placed around the tricuspid annulus and entrainment mapping from within the low right atrial isthmus. After confirmation of the arrhythmia mechanism with these techniques, an anatomic approach was used to create a linear lesion between the inferior tricuspid annulus and the eustachian ridge at the anterior margin of the inferior vena cava. In order to demonstrate successful ablation, mapping techniques were employed to show that bi-directional conduction block was present in the low right atrial isthmus.
Results: Successful ablation was achieved in 26/27 patients (96%). In one patient with a grossly enlarged right atrium, isthmus block could not be achieved. Of the 26 patients with successful ablation, mere has been one recurrence of typical flutter (4%) during a mean follow-up period of 5.5±2.7 months. This patient underwent a successful repeat ablation procedure. Of eight patients with documented clinical atrial fibrillation (in addition to atrial flutter) prior to the procedure, five continued to have atrial fibrillation following the ablation. There were no procedural complications and all patients had normal AV conduction at the completion of the ablation.
Conclusions: RF ablation is a highly effective and safe procedure for cure of atrial flutter. In patients with chronic or recurrent forms of atrial flutter RF ablation should be considered as a first line therapeutic option.     

Recording of double atrial potentials as a marker for isthmus block during ablation of atrial flutter

Radiofrequency ablation is an established method for treatment of type I atrial flutter. The assessment of creation of complete bidirectional isthmus block following linear ablation of the isthmus is an integral part of ablation procedure. Conventionally, bidirectional isthmus block is tested by pacing on either side of ablation line and looking for reversal of activation sequence in the right atrium. We looked at the feasibility of recording double potentials, separated by an isoelectric interval along the ablation line as an alternative method to demonstrate bidirectional isthmus block. An attempt was made to record the double potentials following linear ablation of the cavotricuspid isthmus. Following ablation, bidirectional isthmus block was also tested by pacing from the coronary sinus os and the low-lateral right atrium. We could demonstrate double potentials in 9 of the 11 patients in whom we attempted to record them following linear ablation of flutter. The presence of bidirectional block by pacing from coronary sinus os and low lateral right atrium could be demonstrated in 10 (91%) patients. Thus, double atrial potentials, separated by an isoelectric interval can be demonstrated following ablation of atrial flutter. Double potentials, if demonstrable on coronary sinus os and low lateral right atrium pacing, could serve as an alternative marker of isthmus block.     

Electrophysiologic characteristics of sustained ventricular tachycardia occurring after repair of tetralogy of fallot

The electrophysiologic characteristics of sustained ventricular tachycardia occurring after total repair of tetralogy of Fallot are reported. Four patients, 8 to 31 years of age, who had spontaneous episodes of sustained ventricular tachycardia underwent electrophysiologic study to determine the mechanism and site of origin of the tachycardia. In each patient, the tachycardia could be reproducibly initiated and terminated by programmed electrical stimulation. In two patients, initiation and maintenance of the tachycardia depended on the development and perpetuation of continuous electrical activity in the right ventricular outflow tract. These observations suggested a reentrant mechanism. In each patient, catheter endocardial mapping demonstrated the site of origin to be the right ventricular outflow tract. In two patients intraoperative mapping showed the reentrant circuit originating at the site of healed right ventriculotomy site. We conclude that sustained ventricular tachycardia after repair of tetralogy of Fallot in our patients was caused by reentry at the site of the previous operation in the right ventricular outflow tract.     

Wide QRS-complex tachycardia with variable VA-conduction: what is the mechanism?

We describe the case of a 16-year-old woman with a surgically corrected tetralogy of Fallot presenting with recurrent wide-QRS-complex tachycardia. The tachycardia could be induced and terminated with ventricular stimulation only. QRS morphology during sinus rhythm and tachycardia was identical and variable VA-conduction was observed. Mapping of the tachycardia showed that variations of HH intervals preceded VV intervals. Therefore, a mechanism involving re-entry within the bundle branches was suggested. However, detailed mapping showed cranial to caudal depolarization of the His bundle, leading to the diagnosis of atrioventricular node re-entrant tachycardia. The tachycardia was abolished by radiofrequency catheter ablation of the slow AV nodal pathway. We conclude that variable VA conduction can occur in patients with atrioventricular node re-entrant tachycardia. The atrial tissue is not always an integral part of the re-entrant circuit.     

New Endpoint for Ablation of Ventricular Tachycardia: Change in QRS Morphology with Pacing at Protected Isthmus as Index of Isthmus Block

New Endpoint for Ablation of Ventricular Tachycardia. Introduction: Endpoints confirming block in the critical isthmus in sinus rhythm and with pace mapping have not been established. Methods and Results: A 44‐year‐old man with a history of Tetralogy of Fallot presented with recurrent ventricular tachycardia (VT). Entrainment mapping was consistent with a macroreentrant circuit rotating in a clockwise fashion under the pulmonic valve. After termination of the VT in a critical isthmus located on the conal free wall, a pace map proximal to the site of successful ablation was consistent with a change in QRS morphology. This change in QRS morphology suggested critical isthmus block and successful ablation, which was confirmed by noninducibility with programmed stimulation. Conclusion: Evidence of conduction block can be used as an additional endpoint for successful ablation of VT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 320–324, March 2010)     

Arteriosclerotic heart disease following correction of tetralogy of Fallot

An increasing number of people who have undergone surgical repair of tetralogy of Fallot are living long lives. Several late sequelae of corrected tetralogy of Fallot have been found, including residual ventricular septal defect, restenosis of the pulmonary outflow tract, ventricular tachycardia, and right ventricular failure from pulmonary insufficiency. A long-term survivor of corrected tetralogy of Fallot is reported with acquired coronary artery disease unrelated to the congenital anomaly or its correction as an additional cause of late morbidity in this select but growing population of patients.     

Monomorphic ventricular tachycardia related to Wolff-Parkinson-White surgery.

Monomorphic ventricular tachycardia (MVT) is well described in patients who have had a ventricular scar due to repair of congenital heart disease. A 54-year-old woman presented with MVT 20 years after WPW surgery for a left-sided accessory pathway. The circuit was mapped to an area at the base of the left ventricle consistent with the incision described in the operation report. Entrainment confirmed the re-entrant circuit. Successful radiofrequency ablation was performed in a zone of slowed conduction consistent with the circuit isthmus. Any iatrogenic ventricular scar may form the substrate for MVT and be treated with standard electrophysiology techniques.     

右心室造影结合CARTO标测指引射频导管消融法洛四联症术后室性心动过速

目的:应用右心室造影结合电解剖标测（CARTO标测）指引经盐水灌注射频导管消融法洛四联症术后室性心动过速（VT）5例。方法: 5例患者中4例为男性,6～38岁,法洛四联症术后2～16年反复出现阵发性心悸,发病时体表心电图均表现为持续性VT且药物治疗无效,2例有晕厥史。均不同意放置埋藏式心脏复律除颤器（ICD）。应用右心室造影结合CARTO标测指引消融VT的方法如下:首先进行右心室造影明确右心室解剖及肺动脉瓣环位置,并作为解剖路标,在窦律时行右心室电压标测,标记低电压手术疤痕和室间隔补片区域,明确VT发生基质。而后心室程序电刺激诱发VT,如血流动力学稳定,则在VT时行拖带标测,确定并消融VT关键峡部;如血流动力学不稳定或不能诱发持续性VT,则在窦律时行起搏标测,在局部起搏时和VT有相同或相近的体表心电图并伴较长的刺激到QRS波时间的部位消融,并消融有晚电位或碎裂电位的电屏障区。结果: 5例患者可诱发出6种形态VT,VT周长230～310 ms,5种为持续性VT,其中1种血流动力学不稳定;另1种为非持续性VT。3例患者在VT时标测和消融,2例患者在窦律下标测后消融。6种形态VT均为疤痕折返机制,6种VT均消融成功。随访12～30月,无VT复发。结论: 右心室造影能明确法洛四联症术后右心室及肺动脉瓣环解剖结构,CARTO标测可以定位室间隔补片和外科手术疤痕,在明确这些VT发生基质基础上指引射频导管消融法洛四联症术后VT可取得较高的成功率。     

Aborted Sudden Cardiac Death Due to Radiofrequency Ablation Within the Coronary Sinus and Subsequent Total Occlusion of the Circumflex Artery

We report a case of aborted sudden cardiac death and subsequent development of malignant drug‐refractory incessant ventricular tachycardia/fibrillation in a patient with acute coronary artery occlusion following radiofrequency ablation within the CS. Catheter ablation is a well‐established therapy for treatment of atrial fibrillation (AF). In patients with longstanding persistent AF extensive left atrial ablation and ablation inside the coronary sinus (CS) is frequently performed. Perimitral flutter following AF ablation is the most common form of left atrial macroreentry, especially in patients with previous ablation of complex fractionated electrograms and incomplete linear lesion sets within the left atrium. Successful ablation of this type of tachycardia is generally difficult and in about 60–70% patients requires additional ablation within the CS to achieve termination of tachycardia or/and left atrial isthmus (LAI) block. A limited number of case reports have been published describing acute coronary artery occlusion during or immediately after LAI ablation within the CS. This case exhibits a potential lethal risk of radiofrequency ablation within the CS.     

起搏标测指导下射频消融器质性心脏病并发单形性室性心动过速

目的探讨起搏标测指导下射频消融器质性心脏病并发单形性室性心动过速(室速)的可行性和有效性。方法7例器质性心脏病患者,包括肥厚型心肌病4例,扩张型心肌病1例,冠心病、陈旧性心肌梗死1例,室间隔缺损修补术后1例。所有患者均为单形性室速。7例患者均在起搏标测下在室速折返环出口或病灶起源点行多靶点消融。以标测过程中出现与临床QRS波形态相同或相似的短阵室速或频发室性期前收缩为有效消融靶点。结果7例患者中4例为右室流入道室速,2例为左室流出道室速,1例为左室流入道室速。其中1例室速发生时血流动力学不稳定,1例程序刺激及药物不易诱发(术中仅记录到1次与临床发作相同的短阵室速)。7例患者分别完成消融3~10个靶点,其中2例手术失败。1例患者1周后再次行射频消融手术失败。所有患者术中、术后均无并发症发生。随访24~38(平均29.5)个月,其中6例患者在未服用抗心律失常药情况下(包括1例2次手术者)无室速复发。结论起搏标测指导下行多靶点消融能有效治疗器质性心脏病单形性室速;对于血流动力学不稳定性室速或程序刺激及药物不易诱发的室速起搏标测更有其应用价值。     

Hybrid epicardial and endocardial ablation of persistent or permanent atrial fibrillation: a new approach for difficult cases

Background : Although percutaneous epicardial catheter ablation (PECA) has been used for the management of epicardial ventricular tachycardia, the use of PECA for atrial fibrillation (AF) has not yet been reported.
Objective: To evaluate the efficacy and feasibility of a hybrid PECA and endocardial ablation for AF.
Methods: We performed PECA for AF in five patients (48.6 ± 8.1 years old, all male, four redo ablation procedures of persistent AF with a risk of pulmonary vein (PV) stenosis, one de novo ablation of permanent [AF]) after an endocardial AF ablation guided by PV potentials and 3D mapping (NavX). Utilizing an open irrigation tip catheter, a left atrial (LA) linear ablation from the roof to the perimitral isthmus or localized ablation at the junction between the LA appendage and left-sided PVs or ligament of Marshall (LOM) was performed.
Results: PECA of AF was successful in all patients with an ablation time of <15 minutes. The left-sided PV potentials were eliminated by PECA in all patients. Bidirectional block of the perimitral line was achieved in two of two patients and a left inferior PV tachycardia with conduction block to the LA was observed during the ablation in the area of the LOM in one patient. A hemopericardium developed in one patient, but was controlled successfully. During 8.0 ± 6.3 months of follow-up, all patients have remained in sinus rhythm (four patients without antiarrhythmic drugs).
Conclusion: A hybrid PECA of AF is feasible and effective in patients with redo-AF ablation procedures and at risk for left-sided PV stenosis or who are resistant to endocardial linear ablation.     

对比观察射频消融右房后位峡部和间隔峡部治疗典型心房扑动的疗效

对比观察射频消融右房后位峡部和间隔峡部治疗心房扑动 (简称房扑 )两种方法的疗效。 41例房扑患者随机分为后位峡部组 ( 18例 )和间隔峡部组 ( 2 3例 ) ,消融线径分别为三尖瓣环—下腔静脉和三尖瓣环—欧氏嵴。成功消融终点为房扑不能诱发和峡部呈完全性双向阻滞。结果 :40例消融成功 ( 97.6 % ) ,无并发症。后位峡部组 3例和间隔峡部组 2例在首选消融方法失败后 ,改用另一种消融方法获得成功。两组患者的放电次数和手术时间均无显著性差异。平均随访 12 .4± 6 .8个月 ,在后位峡部消融成功者中 ,有 2例房扑复发。结论 :射频消融右房后位峡部和间隔峡部治疗房扑均安全有效 ,两种方法互补可以提高消融的成功率