Infusion Needle Radiofrequency Ablation for Treatment of Refractory Ventricular Arrhythmias

Background

Catheter ablation is effective for eliminating most drug-refractory ventricular arrhythmias (VA). However, a major reason for procedural failure is arrhythmia originating deep within the myocardium where it is inaccessible to conventional endocardial or epicardial approaches. Affected patients have limited therapeutic options.

Heart transplantation in therapy-resistant, recurrent ventricular tachycardias and ventricular fibrillation

In life-threatening, drug resistant ventricular tachycardia (VT) or ventricular fibrillation (VF), orthotopic heart transplantation should be considered as an alternative to a directed surgical approach or to the implantation of an automatic defibrillator. We report on nine patients with primary VT or VF who underwent transplantation. These comprised eight men and one woman with a mean age of 35 years (range, 19-51 years); dilative cardiomyopathy was present in seven and coronary artery disease in two. Left ventricular ejection fraction was 19% (11-26%), arrhythmia was recurrent VF in five cases, recurrent VT in two, and recurrent VT/VF in two. Two patients died, one due to acute rejection, and the other 8 months postoperatively due to chronic rejection. The seven other patients are all asymptomatic and leading normal lives without arrhythmias or antiarrhythmic drug therapy. Based on our preliminary experience, some advantages and disadvantages of heart transplantation are discussed in comparison with other treatment modalities. Despite limited indications for orthotopic heart transplantation we feel that it should become the therapy of first choice in young patients with progressive, surgically incorrectable cardiac disease complicated by drug resistant VT or VF.     

Usefulness of programmed stimulation in idiopathic dilated cardiomyopathy

The response to programmed electrical stimulation and the clinical outcome was determined in 47 patients with nonischemic dilated cardiomyopathy (DC). Thirteen patients (group 1) presented with sustained uniform ventricular tachycardia (VT), 14 (group 2) presented with cardiac arrest and 20 (group 3) presented with nonsustained VT. The mean ejection fraction of the study population was 28 +/- 9%. The response to programmed stimulation was related to arrhythmia presentation. In all patients in group 1 sustained, uniform VT was induced, compared with 1 patient in group 2 and 2 patients in group 3 (p less than 0.001). There were 14 sudden cardiac deaths and 1 cardiac arrest during a mean follow-up of 18 +/- 14 months. The only 4 patients who presented with sustained VT or a cardiac arrest in whom sustained arrhythmia induction was suppressed with antiarrhythmic therapy remain alive. Nine of the 23 patients (4 in group 2 and 5 in group 3) in whom no sustained ventricular arrhythmia was induced died suddenly, with 5 of the 9 receiving empiric antiarrhythmic therapy. Three other patients, who had a slower and hemodynamically tolerated VT at the time of arrhythmia induction, died suddenly. Thus, in patients with nonischemic DC, uniform, sustained VT is always and almost solely initiated in patients who present with this arrhythmia; although few patients presenting with sustained VT or cardiac arrest have inducibility of the arrhythmias suppressed with therapy, if it is suppressed the patient appears to have a good prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Catheter ablation of ventricular tachycardia in ischaemic and non-ischaemic cardiomyopathy: where are we today? A clinical review

According to the current guidelines, patients with ischaemic cardiomyopathy (ICM) or non-ischaemic cardiomyopathy (NICM) at risk for sudden cardiac death should undergo implantation of an implantable cardioverter-defibrillator (ICD). Although ICDs effectively terminate ventricular arrhythmias, the arrhythmogenic substrate remains unchanged or may progress over time, resulting in recurrent ICD shocks. Defibrillator shocks increase mortality and worsen quality of life. Evidence from two prospective randomized trials on outcome in patients with ischaemic heart disease undergoing catheter ablation for ventricular tachycardia (VT) suggests that ablation prevents recurrence of VT and decreases the number of ICD shocks. This review will highlight the recent progress made in the ablative treatment of VT in patients with ICM and NICM.     

Long-term reproducibility of responses to programmed cardiac stimulation in spontaneous ventricular tachyarrhythmias

Programmed electrical stimulation (PES) of the heart has been used to initiate and terminate ventricular tachyarrhythmias under controlled conditions in patients in whom these arrhythmias have occurred spontaneously. The long-term reproducibility of the response to programmed cardiac stimulation in patients with ventricular arrhythmias is unknown. Seventeen patients with previously documented spontaneously occurring ventricular tachyarrhythmias were evaluated: 5 with nonsustained ventricular tachycardia (VT), 10 with sustained VT and 2 with ventricular fibrillation. The underlying cardiac diagnosis was atherosclerotic coronary heart disease (CAD) in 11 patients, dilated cardiomyopathy in 2 patients, congenital heart disease in 1 patient and no structural heart disease in 3. All patients underwent PES in the absence of antiarrhythmic drug treatment, and patients with inducible VT underwent serial electrophysiologic-pharmacologic testing in an attempt to suppress the arrhythmia. All 17 patients were reexamined with PES at a mean of 18 months (range 2 to 42) after their initial electrophysiologic study, during which time none had a myocardial infarction or intervening cardiac surgery. Repeat electrophysiologic studies, performed in the absence of antiarrhythmic agents, were undertaken because of drug intolerance, availability of new drugs, recurrent arrhythmia or preoperative reevaluation. All 11 patients with CAD had inducible VT on both the first and second electrophysiologic evaluation. Of the 6 patients with no CAD, only 1 had inducible VT on both occasions. Thus, long-term reproducibility of PES-induced VT in patients with stable CAD appears to be high.     

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.     

Catheter-based Ablation for Ventricular Arrhythmias

Catheter ablation for patients with recurrent ventricular arrhythmias has emerged as an important and effective treatment option. The approach to ablation, and the risks and likely efficacy are determined by the nature of the severity and type of underlying heart disease. Although implantable defibrillators remain the corner stone for prevention of sudden cardiac death, ablation successfully reduces tachycardia recurrences and storms of ventricular arrhythmias triggering defibrillator shocks in patients with structural heart disease. Our understanding of idiopathic ventricular tachycardia (VT) has grown substantially with several new sites of VT origin recognized in recent years. Ablation is often curative for idiopathic VT. This review discusses common mechanisms and clues to diagnosis of the various VTs, and current advances in ablation options. In particular, endocardial ablation techniques have been complemented by newer approaches such as percutaneous epicardial ablation. In rare cases, transcoronary alcohol ablation can be effective for life-threatening arrhythmia.     

Transvenous dual site left ventricular pacing plus biventricular pacing for the management of refractory ventricular tachycardia

This is a case report of a male patient with nonischemic cardiomyopathy who had severely depressed left ventricular systolic function and functional class III congestive heart failure (CHF). He also had left bundle branch block (LBBB) and recurrent ventricular tachycardia (VT). Though the patient’s CFH functional class improved after implantation of a transvenous biventricular ICD system, recurrent VT episodes required the initiation of amiodarone. After an improved condition for 28 months, recurrent VT episodes led to multiple consecutive ICD shocks, which constituted an electrical storm and a battery status of elective replacement indicator (ERI). The recurrent VT episodes were suppressed with intravenous amiodarone and lidocaine. As Radiofrequency ablation was declined by the patient, a new left ventricular (LV) lead was transvenously added, providing biventricular and dual site LV pacing. After this intervention the arrhythmia subsided and the intravenous antiarrhythmic medications were stopped. No episodes of sustained VT leading to ICD shocks were observed for the following 9 months. The events in this case suggest that dual site LV pacing with biventricular pacing could be an alternative strategy for the management of refractory VT.     

Ablation of epicardial macroreentrant ventricular tachycardia associated with idiopathic nonischemic dilated cardiomyopathy by a percutaneous transthoracic approach

Characterization of the substrate and mechanism of epicardial ventricular tachycardia (VT) associated with idiopathic nonischemic dilated cardiomyopathy is limited. We report a case of successful mapping and ablation of an epicardial VT by a percutaneous transthoracic approach in a patient with idiopathic dilated cardiomyopathy, frequent VT, and previously unsuccessful endocardial ablation. Evidence of myocardial scar was limited to the epicardium. Electroanatomic and entrainment mapping defined a figure-of-eight macroreentrant circuit within the epicardial scar. VT terminated at the onset of low-power radiofrequency application to the central isthmus of the circuit. VT was no longer induced and did not recur during long-term follow-up.     

Evaluation of Saline-Enhanced Radiofrequency Needle-Tip Ablation for Ventricular Tachycardia (SERF VT CANADA Trial)

BackgroundEndocardial catheter ablation for ventricular tachycardia (VT) may fail owing to the inability to deliver transmural lesions. Saline-enhanced radiofrequency (SERF) ablation uses a needle-tip catheter that is placed at varying depths into the myocardial tissue and heated saline solution is injected along with radiofrequency power (RF), creating fully transmural lesions. We report the first in-human SERF ablation for VT in Canada.MethodsTwenty-five patients with ischemic and nonischemic cardiomyopathy, with recurrent monomorphic drug-refractory VT who had failed a prior catheter ablation underwent SERF ablation in 3 different centres in Canada. After a voltage map, the mapping catheter was replaced with the needle-tipped ablation catheter, which was located perpendicular to the myocardium and extended either 6 or 8 mm into the tissue. Sterile saline solution was infused at a flow rate of 10 mL/min and at 60 °C, and 20-50 W RF was used.ResultsBaseline left ventricular ejection fraction was 33.3 ± 8.6%, mean age was 69.5 ± 6.4 years; 92% were male. From 43 clinical VTs induced, 42 were ablated and 266 SERF lesions were delivered (10.6 ± 4.9 per patient). Of the 42 treated clinical VTs, 41 VTs (98%) were noninducible and 24 patients (96%) had their VT eliminated. At 6 months’ follow-up, 42% of patients were free from VT and there was a 73% reduction in shocks.ConclusionsSERF ablation is feasible and permits control of symptomatic monomorphic VT in drug-refractory patients with a prior failed ablation.     

Surgical Cardiac Sympathetic Denervation for Ventricular Arrhythmias: A Systematic Review

Ventricular arrhythmias are potentially life-threatening disorders that are commonly treated with medications, catheter ablation and implantable cardioverter defibrillator (ICD). Adult patients who continue to be symptomatic, with frequent ventricular arrhythmia cardiac events or defibrillation from ICD despite medical treatment, are a challenging subgroup to manage. Surgical cardiac sympathetic denervation has emerged as a possible treatment option for people refractory to less invasive medical options. Recent treatment guidelines have recommendedcardiac sympathectomy for ventricular tachycardia (VT) or VT/fibrillation storm refractory to antiarrhythmic medications, long QT syndrome, and catecholaminergic polymorphic VT, with much of the data pertaining to pediatric literature. However, for the adult population, the disease indications, complications, and risks of cardiac sympathectomy are less understood, as are the most effective surgical cardiac denervation techniques for this patient demographic. This systematic review navigates available literature evaluating surgical denervation disease state indications, techniques, and sympathectomy risks for medically refractory ventricular arrhythmia in the adult patient population.     

Successful catheter ablation of two types of ventricular tachycardias triggered by cardiac resynchronization therapy: a case report

We report a case of a patient with nonischemic dilated cardiomyopathy and implantable cardioverter-defibrillator, in whom an upgrade to biventricular pacing triggered multiple episodes of ventricular tachycardias (VTs) of two morphologies. First VT presented as repetitive nonsustained arrhythmia of the same morphology as isolated ectopic beats, suggesting its focal origin. Second VT was reentrant and was triggered by the former ectopy, leading to a therapy from the device. Electroanatomical mapping of the left ventricle revealed relatively small low voltage area in the left ventricular outflow tract and identified both an arrhythmogenic focus as well as critical isthmus for reentrant VT. Radiofrequency catheter ablation successfully abolished both VTs. After the procedure, biventricular pacing was continued without any recurrences during a period of 24 months. The report emphasizes the role of catheter ablation in management of VTs triggered by cardiac resynchronization therapy.     

Ventricular tachycardia in repaired congenital heart disease

Ventricular arrhythmias are an important cause of late morbidity and sudden cardiac death in the growing population of adults with repaired congenital heart disease. Risk stratification remains challenging because of the heterogeneity of the malformations and the surgical approaches. Therapeutic interventions depend on the type of ventricular arrhythmia, which can be polymorphic ventricular tachycardia (VT) or ventricular fibrillation in patients without ventricular scars, but also potentially fatal monomorphic reentrant VTs, typical for patients with ventricular scars or obstacles. Advances in surgical techniques have improved survival and have important implications for the arrhythmia substrates and prognosis. Over the past few decades, progress has been made to determine the anatomical basis for monomorphic VT in patients with ventricular surgical scars and patch material. These substrates can be currently identified and targeted during sinus rhythm by radiofrequency catheter or surgical ablation without the need for VT induction. The review provides an update on the evolving surgical approaches, the changing VA substrates, and the potential consequences for individualized risk assessment and tailored treatment.     

Advances in Ablation of Ventricular Tachycardia in Nonischemic Cardiomyopathy

Management of patients with nonischemic cardiomyopathy (NICM) and ventricular tachycardia (VT) remains challenging. The role of catheter ablation for VT continues to evolve for these patients. Prior reports have described the location of the arrhythmogenic substrate for patients with NICM to be frequently located along the basal left ventricle, with an epicardial predilection. Furthermore, predictors for identifying whether mapping the endocardium or epicardial surface of the heart have been identified for improved success of VT ablation in this patient population. This chapter will review the latest advances in catheter ablation of ventricular tachycardia in patients with NICM.     

Mapping and radiofrequency catheter ablation of the three types of sustained monomorphic ventricular tachycardia in nonischemic heart disease

INTRODUCTION: Sustained monomorphic ventricular tachycardia (VT) associated with nonischemic cardiomyopathy (CMP) is uncommon. Optimal approaches to catheter mapping and ablation are not well characterized, but they are likely to depend on the VT mechanism. The purpose of this study was to evaluate the mechanisms of sustained monomorphic VT encountered in nonischemic CMP and to assess the feasibility, safety, and efficacy of catheter radiofrequency ablation for treatment. METHODS AND RESULTS: Twenty-six consecutive patients with nonischemic CMP referred for management of recurrent VT were studied. In 16 (62%) patients, VT was related to a region of abnormal electrograms consistent with scar and the response to pacing suggested a reentrant mechanism. In 5 (19%) patients, VT was due to bundle branch or interfascicular reentry. In 7 (27%) patients, the VT mechanism was focal automaticity, 4 of whom had evidence of tachycardia-induced CMP. After catheter ablation targeting parts of reentrant circuits, VT was not inducible in 8 (53%) of 15 patients with scar-related reentry, was modified in 5 (33%) patients, and still was inducible in 2 (13%) patients. Ablation was successful in 5 of 5 patients with bundle branch reentry and in 6 of 7 patients with a focal automaticity mechanism. Overall, catheter ablation abolished clinical recurrence of VT in 20 (77%) of 26 patients during a follow-up of 15 +/- 12 months. CONCLUSION: Three different mechanisms of VT are encountered in patients with nonischemic CMP. The mapping and ablation approach varies with the type of VT. In this selected population, the overall efficacy was 77%.     

Isolated Potentials and Pace‐Mapping as Guides for Ablation of Ventricular Tachycardia in Various Types of Nonischemic Cardiomyopathy

Nonischemic Cardiomyopathy and Ventricular Tachycardia. Background: In patients with prior infarction, isolated potentials (IPs) during sinus rhythm reflect fixed scar and often indicate sites critical for ventricular tachycardia (VT). The purpose of this study was to determine the value of IPs in conjunction with pace‐mapping to guide VT ablation in patients with various types of nonischemic cardiomyopathy. Methods: Mapping and ablation of VT were performed in 35 consecutive patients (26 men, age 55 ± 13 years, ejection fraction 0.31 ± 0.14) with VT and various etiologies of nonischemic cardiomyopathy. Pace‐mapping was performed at sites with low voltage. Radiofrequency energy was delivered at sites with concealed entrainment or matching pace‐maps. Results: One hundred ninety‐five VTs (mean cycle length 363 ± 88 ms) were induced. Sites with prespecified ablation criteria displaying IPs during sinus rhythm were recorded in 21 of 35 patients (60%, IP‐positive). In these patients, a total of 216 sites meeting prespecified ablation criteria were identified and 146 of 216 sites (68%) displayed IPs. Fifteen of 21 IP‐positive patients (71%) no longer had inducible VT after ablation. In 14 of 35 patients, no sites with IPs where prespecified ablation criteria were met were identified (IP‐negative) despite combined endocardial and epicardial mapping in 7 of 14 patients. Only 1 of 14 IP‐negative patients (7%) no longer had inducible VT at the end of the ablation procedure. During a mean follow‐up of 18 ± 13 months, 14 of 21 IP‐positive patients (67%) remained arrhythmia‐free, compared to 1 of 14 IP‐negative patients (7%; P < 0.01). Half of the IP‐negative patients had major adverse events due to recurrent arrhythmias, compared to none in IP‐positive patients. Conclusion: IPs in conjunction with pace‐mapping are helpful for identifying critical isthmus areas for ablation of VT in patients with various types of nonischemic cardiomyopathy. Patients with nonischemic cardiomyopathy in whom the arrhythmogenic substrate is characterized by IPs have a more favorable outcome than patients in whom IPs are absent. J Cardiovasc Electrophysiol, Vol. 21, pp. 1017‐1023, September 2010)     

射频消蚀术治疗右室流出道起源的室性心律失常

射频消蚀治疗无器质性心脏病基础、起源于右室流出道的室性心律失常,其中室速与室早各2例。治疗后3例心律失常消失,1例术后发作一次非持续性室速,再用氟卡胺变为有效。随访3—6个月,未发现与消蚀有关的并发症。     

Ablation of ventricular tachycardia in patients with nonischemic cardiomyopathy

Nonischemic Cardiomyopathy. Mapping and ablation of ventricular tachycardia (VT) in patients with nonischemic cardiomyopathy can be challenging. In this article, we describe the approach to VT in patients with nonischemic cardiomyopathy that we use at the University of Michigan. Imaging, especially with delayed enhanced cardiac magnetic resonance imaging, plays a central role in planning a mapping and ablation procedure. During the mapping procedure, pace-mapping in conjunction with voltage maps focusing on areas with isolated potentials helps to identify scar areas that are critical for VT in these patients.     

Endomyocardial substrate of ventricular arrhythmias in patients with autoimmune rheumatic diseases

Introduction

Delayed enhancement-magnetic resonance imaging (DE-MRI) has demonstrated that nonischemic cardiomyopathy is mainly characterized by intramural or epicardial fibrosis whereas global endomyocardial fibrosis suggests cardiac involvement in autoimmune rheumatic diseases or amyloidosis. Conduction disorders and sudden cardiac death are important manifestations of autoimmune rheumatic diseases with cardiac involvement but the substrates of ventricular arrhythmias in autoimmune rheumatic diseases have not been fully elucidated.

Methods and Results

20 patients with autoimmune rheumatic diseases presenting with ventricular tachycardia (VT) (n = 11) or frequent ventricular extrasystoles (n = 9) underwent DE-MRI and/or endocardial electroanatomical mapping of the left ventricle (LV). Ten patients with autoimmune rheumatic diseases underwent VT ablation. Global endomyocardial fibrosis without myocardial thickening and unrelated to coronary territories was detected by DE-MRI or electroanatomical voltage mapping in 9 of 20 patients with autoimmune rheumatic diseases. In the other patients with autoimmune rheumatic diseases, limited regions of predominantly epicardial (n = 4) and intramyocardial (n = 5) fibrosis or only minimal fibrosis (n = 2) were found using DE-MRI. Endocardial low-amplitude diastolic potentials and pre-systolic Purkinje or fascicular potentials, mostly within fibrotic areas, were identified as the targets of successful VT ablation in 7 of 10 patients with autoimmune rheumatic diseases.

Conclusion

Global endomyocardial fibrosis can be a tool to diagnose severe cardiac involvement in autoimmune rheumatic diseases and may serve as the substrate of ventricular arrhythmias in a substantial part of patients.     

The role of percutaneous left ventricular assist devices during ventricular tachycardia ablation

Ventricular tachycardia (VT) is a common but serious arrhythmia that significantly adds to the morbidity and mortality of patients with structural heart disease. Percutaneous catheter ablation has evolved to be standard therapy to prevent recurrent implantable cardioverter defibrillator shocks from VT in patients on antiarrhythmia medications. Procedural outcomes in patients with structural heart disease are often limited by haemodynamically unstable VT. Although substrate- and pace-mapping techniques have become increasingly popular for VT ablation, these approaches can often times may not address inducible clinical and non-clinical VTs. Activation and entrainment mapping can help the operator target VT exit sites in a precise fashion minimizing the amount of radiofrequency ablation needed for a successful ablation. An evolving alternative strategy that allows induction and mapping of VT in the setting of severe cardiomyopathy and haemodynamic instability is through maintaining perfusion with a percutaneous ventricular assist device (pVAD). This review will discuss these pVAD technologies, distinguish technical applications of use, highlight the published clinical experience, provide a clinical approach for support device selection, and discuss use of these technologies with current mapping and navigational systems.