Recurrent Polymorphic Ventricular Tachycardia Complicating Radiofrequency Catheter Ablation of the Atrioventricular Junction

Recurrent ventricular tachycardia and ventricular fibrillation were observed immediately after RF ablation of the AV junction in a 64-year-old man. This arrhythmia was preceded by ventricular bigeminy and a long-short sequence. It was not associated with prolongation of the QT interval compared to baseline, and recurred 3 months later despite ventricular pacing at 90 beats/min. This is the first reported case of sustained ventricular arrhythmia complicating RF AV junction ablation despite rapid ventricular pacing, and recurring 3 months after discharge. It may explain the rare cases of sudden death complicating this procedure.     

Ventricular Fibrillation and Sudden Death After Radiofrequency Catheter Ablation of the Atrioventricular Junction

Two hundred thirty-five patients underwent RF catheter abhtion of AV conduction for symptomatic drug refractoiy AF (84%), atrial flutter (9%), and atrial tachycardia (7%). In the first 100 patients, postahlation pacing was not prospectively set at any specific rate and was always ≤ 70 beats/min. In the next 135 patients, postabiotion pacing was prospectively set at 90 beats/min for 1–3 months. Six of the first 100 patients (6%) had VF or sudden death after the RF procedure and none (0%) of the next 135 patients did (P < 0.05). One of the six patients had recurrent VF 4 days after the ablation. Five patients were successfully resuscitated and one patient died. There were no statistically significant differences between patients with and without (aborted) sudden death or between the first 100 and the next 135 patients with respect to age, sex, underlying heart disease, EF, number of RF applications, or leftor right-sided approach of the procedure. VF mostly occurred during episodes of slow ventricular escape rhythms or during slow ventricular pacing. We conclude that malignant ventricular arrhythmias and sudden death are possible complications of RF ablation of the AV junction. The mechanism of these complications could have a bradycardia dependent nature and it seems that the occurrence of malignant arrhythmias can be prevented by temporarily pacing the heart at relatively fast rates immediately after ablation.     

Bradycardia Dependent QT Prolongation and Ventricular Fibrillation Following Catheter Ablation of the Atrioventricular Junction witb Radiofrequency Energy

Recurrent ventricular fibrillation was observed in a 67-year-old woman following catheter ablation of the AV junction using radiofrequency energy. This serious complication has been reported following direct current energy ablation of the AV junction, but not after using radiofrequency energy. This life-threatening arrhythmia seemed pause and bradycardia dependent. It was followed by QT_c prolongation of the QRS escape rhythm 1 day after the procedure. Ventricular arrhythmias were suppressed by rapid ventricular pacing.     

Successful Radiofrequency Current Catheter Ablation of Sustained Ventricular Tachycardia

We performed radiofrequency current catheter ablation in two patients with nonischemic sustained ventricular tachycardia (VT). In one patient, two morphologically distinct VTs were induced by electrical stimulation. One showed right bundle branch block pattern and the other left bundle branch block pattern. The earliest site of activation during each VT was determined at the septum of the right ventricle. However, these two sites were close to the His-bundle elecfrogram recording area. In the other patient, a VT with a left bundle branch block pattern occurred spontaneously after the administration of isoproterenol. The earliest site of activation during VT was determined at the outflow tract of the right ventricle. During tachycardia, radiofrequency current ablation (40 W ± 30 sec) was delivered to the earliest site of activation, A few seconds after fulguration, each VT was terminated and additional radio-frequency currents were given near these sites. After the ablation, VT could not be induced by the electrical stimulations, nor did it recur. No side effects were observed and the atrioventricular conduction remained intact. We feel that nonischemic VTs could possibly be treated by using radiofrequency current catheter ablation.     

Results of Catheter Ablation of Ventricular Tachycardia Using Direct Current Shocks

Thirty-three patients with recurrent ventricular tachycardia (VT) underwent catheter ablation with direct-current shocks. One to four shocks of 100–300 joules were delivered to the presumed VT exit sites as identified by endocardial mapping and pace mapping. Fifteen patients (45%) had no recurrence of symptomatic VT during a follow-up interval of 15.5 ± 10 months (mean ± standard deviation). Five patients experienced six nonfatal complications (new VT or ventricular fibrillation, transient neurological deficit, atrioventricular block, brachial artery thrombosis). In conclusion, catheter ablation in selected patients with recurrent VT has the potential for preventing recurrences of VT over the long-term and is relatively safe.     

特发性室性心动过速射频导管消融方法探讨

目的：探讨特发性室性心动过速（IVT）的消融方法。方法：对12例IVT患者进行射频消融治疗，源于右心室IVT采用消融导管起搏标测法，以起搏时与VT发作时的12导联心电图QRS波形态与振幅完全相同的起搏部位为消融靶点。并在周围做巩固消融，起源于左心室IVT以激动标测法或寻找P电位。结果：IVT消融成功率91．6％（11／12），1例ILVT在第3次复发射频消融后发生双束支阻滞而安装了VVI永久起搏器。结论：起源于左心室的IVT宜采用激动顺序标测法，起源于右心室的IVT宜采用起搏标测法。对有效靶点周围进行线状或环状消融，有利于提高手术成功率。     

Catheter Ablation for Ventricular Tachycardia from a Diverticulum at the Right Ventricular Outflow Tract

A case is presented of a 73-year-old man with drug resistant ventricular tachycardia that originated from the right ventricular outflow tract. A right ventriculogram showed a diverticulum in the interventricular septum at the right ventricular outflow tract. Low energy radiofrequency catheter ablation within the diverticulum was performed successfully and safely.     

Radiofrequency Catheter Ablation of Refractory Ventricular Tachycardia

Transcatheter radiofrequency ablation of the arrhythmia focus was attempted in a 68-year-old patient with recurrent ventricular tachycardia, both spontaneous and inducible by programmed ventricular stimulation despite treatment with multiple antiarrhythmic drugs. The procedure was performed under local anesthetic without complication. The arrhythmia was not inducible immediately following ablation or 5 days later, and during 5 months follow-up there has been no spontaneous recurrence.     

Current Role of Atrioventricular Junction (AVJ) Ablation

Atrioventricular junction ablation with permanent pacemaker insertion is a highly effective treatment approach in patients with atrial fibrillation that is resistant to other treatment modalities, especially in the elderly or those with severe comorbidities. This effect likely reflects reversal of rapid ventricular rates and regularizing ventricular rates. There is increasing evidence that cardiac resynchronization therapy devices may be beneficial in selected populations after atrioventricular node ablation. The limitations of this approach include continued need for anticoagulation and lifelong pacemaker therapy.     

Catheter Ablation of Idiopathic Left Ventricular Tachycardia

ZARDINI, M., etal .: Catheter Ablation of Idiopathic Left Ventricular Tachycardia . Idiopathic left ventricular tachycardia (ILVT) characterized by right bundle branch block, left axis morphology, response to verapamil and inducibility from the atrium in patients without structural heart disease may represent a distinct clinical entity. We report our experience with catheter ablation of this uncommon arrhythmia using radiofrequency energy (RF) and/or direct current (DC) shocks. Six men and 2 women, aged 16–50 years (mean ± SD, 32 ± 13), had recurrent VT for 16 ± 16 years with a mean frequency of 4 ± 3 episodes/ year. Three patients had syncope during VT. None had identifiable structural heart disease. Catheter ablation was guided by earliest endocardial activation, presence of a high frequency presystolic potential and/or pacemapping of the left ventricle. The left ventricle was accessed via a retrograde aortic approach in 6 patients, a transeptal approach in 1 patient, and a combined approach in the remaining patient. All patients had inducible right bundle branch block morphology, left axis VT with a mean cycle length (CL) of 361 ± 61 ms. A presystolic potential preceding ventricular activation and the His potential during VT was identified in 4 patients. All ablation sites were identified in a relatively uniform location, in the inferoapical left ventricle. Noninducibility of VT was obtained with RF in 3 patients and with DC in 5 patients. In 1 patient, DC delivery after unsuccessful RF prevented further inducibility. Similarly, RF was successful in 1 patient in whom an initial DC attempt was ineffective. Mean total procedure time was 282 ± 51 minutes and mean total fluoroscopy time was 40 ± 15 minutes. There were no complications. One patient treated with DC shock had recurrence of VT during treadmill test the day after ablation and refused repeat ablation. During a mean follow-up of 17 ± 13 months, no VT recurrences or other cardiovascular events occurred. In conclusion, catheter ablation in the inferoapical left ventricle is an effective treatment for this type of ILVT. RF energy can be safely complemented by low energy DC shocks when the former is ineffective.     

Effects on Cardiac Performance of Atrioventricular Node Catheter Ablation Using Radiofrequency Current for Drug-Refractory Atrial Arrhythmias

Patients with atrial fibrillation or atrial flutter (AF) are candidates for radiofrequency (RF) catheter ablation of the atrioventricular (AV) node with the aim being to control heart rate. As patients wilh AF can have markedly impaired ventricular function, information concerning the hemodynamic effects of AV node ablation using RF current would be valuable. Fourteen consecutive patients (mean age 65 ± 3 years) with drug-resistant AF underwent AV node catheter ablation with RF current and had permanent pacemaker implantation. The mean left ventricular ejection fraction (FFJ by two-dimensional echoeardiography immediately before ablation was 42 ± 3% (range 14%–54%) and their mean exercise time was 4.4 ± 0.4 minutes. Complete AV block was achieved in all 14 patients with 6 ± 2 RF applications (range 1–18). There was no evidence of any acute cardiodepressant effect associated with delivery of RF current, and EF 3 days after ablation was 44 ± 4%. By 6 weeks after ablation, the left ventricular EF was significantly improved compared to baseline (47 ± 4% postablation vs 42 ± 3% preahlation; P < 0.05), and this modest increase in EF was accompanied by an improvement in exercise time (5.4 ± 0.4 min). In conclusion, delivery of RF current for AV node catheter ablation in patients with AF and reduced ventricular function is not associated with any acute cardiodepressant effect. On the contrary, improved control of rapid heart rate following successful AV node ablation is associated with a modest and progressive improvement in cardiac performance.     

Coherent Averaging Improves the Evaluation of Left Ventricular Dyssynchrony by Conductance Catheter

Objective  Coherent averaging is a technique to recover the response to repetitively applied stimuli when that response is embedded in random noise. We derived novel indices for left ventricular dyssynchrony estimation from volume-catheter signals using coherent averaging procedure: mechanical dyssynchrony (DYSCoh) internal flow fraction (IFFCoh) and mechanical dispersion (DISPCoh). The percentage power of non-repetitive components in the volume signals (ResTotAvg) was also estimated. The aims of the study were to evaluate the indices, characterizing repetitive and non-recurrent components of the conductance-volume signals, and to assess the ability of these indices to detect the changes in dyssynchrony induced by biventricular pacing (BIV). Methods  We compared the results obtained in 20 heart failure patients indicated to BIV (HF Group) during spontaneous conduction with the results from 12 patients with preserved ventricular function (non-HF Group), and with those obtained during BIV. Results  DISPCoh and ResTotAvg were significantly different in HF compared to non-HF group, and identified HF patients with high accuracy (area under curve at ROC analysis > 0.8). These indices also demonstrated significant differences after BIV (p = 0.047 and p = 0.037 respectively) and␣their baseline values correlated with the acute increase of␣stroke volume (r = 0.64 and r = 0.78, both with p < 0.005). Conclusions  Coherent averaging-based indices permit independent quantification and differentiation of repetitive components of ventricular dyssynchrony from non-recurrent mechanical non-uniformities, which seem associated with HF and conduction disturbances. These indices identified HF patients with high accuracy, and were able to describe the reversal of dyssynchrony caused by BIV and to predict the acute hemodynamic improvement. Perego GB, Valsecchi S, Censi F, Schreuder JJ, Padeletti L. Coherent averaging improves the evaluation of left ventricular dyssynchrony by conductance catheter.     

Coincident Idiopathic Left Ventricular Tachycardia and Atrioventricular Nodal Reentrant Tachycardia: Control by Radiofrequency Catheter Ablation of the Slow Atrioventricular Nodal Pathway

A healthy 37-year-old male presented with a history of frequent palpitations and sustained wide QRS complex tachycardia with a right bundle branch block and left axis morphology. Serial electrophysiological studies revealed two inducible tachycardias, which were shown to represent atrioventricular nodal reentrant tachycardia and idiopathic left ventricular tachycardia. Transformation from one tachycardia to the other occurred spontaneously as well as following atrial or ventricular pacing. Radiofrequency catheter ablation of the slow atrioventricular nodal pathway resulted in cure of atrioventricular nodal reentrant tachycardia and the prevention of spontaneous recurrence of ventricular tachycardia, suggesting a role of atrioventricular nodal reentrant tachycardia in triggering the clinical episodes of ventricular tachycardia. The patient has remained asymptomatic without antiarrhythmic therapy for 8 months.     

Management of Patients After Catheter Ablation of Ventricular Tachycardia

The management of patients after catheter ablation of ventricular tachycardia is not well defined. In this article we summarize recently published results and report our own experience. Factors influencing the clinical outcome of these patients and methods to identify patients with an increased risk of recurrence of ventricular tachycardia are discussed. Furthermore, a review is given on current concomitant therapeutic tools including antiarrhythmic drugs and the implantation of an automatic cardioverter defibrillator.     

Development of an Interactive Computer-Guided Method for Radiofrequency Catheter Ablation of Ventricular Tachycardia

The purpose of this study was to develop a simple computer-guided approach to localizing ventricular tachycardias during ventricular mapping. Six patients with sustained monomorphic ventricular tachycardia were connected to a 32-lead computer body surface mapping system. Isoarea maps of induced ventricular tachycardia were recorded. Then a pacing probe was placed in either the right or left ventricle, and maps were generated from a variety of sites. Differences between ventricular tachycardia and pace map maxima X,Y coordinates were utilized to guide catheter manipulation and localization. In 6 of 6 patients (100%) this method appeared to provide a systematic approach to ventricular tachycardia localization. Computer-generated correlations as well as the X,Y coordinates of the QRS isoarea maxima were used to determine proximity to the ventricular tachycardia foci and direct catheter manipulation. In the next three patients this method was applied prospectively to help guide catheter manipulation during ventricular tachycardia (two right ventricular outflow tract tachycardias, and one left ventricular tachycardia). After a mean of 4.0 ± 1.7 radiofrequency applications, ventricular tachycardia was no longer inducible, and at 7 ± 0 months follow-up there have been no arrhythmia recurrences. We conclude that online computerized body surface mapping can assist in localizing ventricular tachycardia. Differences in maxima during pace maps and in-situ ventricular tachycardias can help with catheter manipulation as well as with more precise identification of focal tachycardias. This technique appears to hold the promise of a simple computer-guided method that may facilitate radiofrequency catheter ablation.     

Long-Term Follow-up of Atrioventricular Junctional Transcatheter Electrical Ablation

Complete data concerning long-term results of transcatheter electrical ablation of the atrioventricular junction is not available. At the request of the French Cardiac Arrhythmia Working group we undertook an inquiry in October 1983. All centers potentially able to perform such procedures were asked to report their experience. Eight centers have performed one case or more, over a period of 3 years, for a total of 91 patients. The mean follow-up completed in all patients in April 1986 was 12 +/- 10 months. The procedure was indicated for a supraventricular arrhythmia resistant to a mean of 3.9 +/- 1.3 classes of antiarrhythmic agents. Atrial flutter or fibrillation in 54 (59%) and atrioventricular nodal reentry in 17 (18%) were the most common arrhythmias. A mean of 2.6 +/- 2.3 electrical shocks (range 1-14 shocks) with a stored energy of 130-400 joules was delivered during 1-5 sessions. Complete heart block was obtained in 83 patients and persisted at the time of discharge from the hospital in 46 patients (50.5%). The immediate complication (within 24 hours after the procedure) included ventricular fibrillation successfully converted (one patient) and nonsustained ventricular tachycardia (three patients). Late complications included one death 3 days after the procedure, in a patient in whom sustained ventricular tachycardia was documented, nonsustained ventricular tachycardia in two patients, sepsis in three patients and pericardial effusion in one patient. At the time of the follow-up, there were three additional deaths related to sepsis due to pacemaker pocket infection in one patient and to preexisting congestive heart failure in two patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Radiofrequency Catheter Ablation of Idiopathic Ventricular Tachycardias in Children

We performed radiofrequency catheter ablation of idiopathic ventricular tachycardia in six children. In four, the ventricular tachycardia originated in the left ventricle, in two it originated in the right ventricular outflow tract. In 5/6 (83%) the RF procedure was successful; there were no complications.     

Radiofrequency Catheter Ablation of the Atrioventricular Junction by a Supravalvular Noncoronary Aortic Cusp Approach

Radiofrequency catheter ablation of the atrioventricular janction is usually achieved from either the right or left atrioventricular junction. We describe a new approach in which the atrioventricular junction was successfully ablated from the supravalvular region of the noncoronary cusp of the aortic valve in an unusual patient in whom conventional approaches were unsuccessful.     

Catheter Ablation for Control of Ventricular Tachycardia: A Report of the Percutaneous Cardiac Mapping and Ablation Registry

Catheter ablation of ventricular tachycardia is a procedure of last resort in critically ill patients. The Percutaneous Cardiac Mapping and Ablation Registry was able to collect data on 88 patients undergoing ablation of ventricular tachycardia foci. The mean following interval for the group was 10 ± 8 months. Results were divided into three categories: Group I patients remained asymptomatic and were on no antiarrhythmic medications (33%); Group II remained asymptomatic and took antiarrhythmic agents (38%): Group III patients were considered unsuccessful and consisted of 29 percent of the total. More than one-third of patients received two shocks; the remainder received from one to five shocks. Overall mortality included four procedure-related deaths and total follow-up mortality was 25 percent. Catheter ablation for ventricular tachycardia should he undertaken only in highly specialized centers with an expert and experienced electrophysiologist with immediate surgical back-up available.     

经导管射频消融治疗特发性室性心动过速患者的护理

目的探讨经导管射频消融治疗特发性室性心动过速患者的护理方法。方法回顾性分析75例行导管射频消融治疗的特发性室性心动过速患者的临床资料。结果发生术后并发症3例,其中穿刺点血肿2例、心脏压塞1例,经精心治疗和护理后均痊愈出院。结论经导管射频消融治疗特发性室性心动过速患者安全有效,手术前后需要密切观察、精心护理、及时发现并协助处理各种并发症。