器质性心脏病室性心动过速的导管消融进展

器质性室性心动过速绝大多数是折返性机制。激动顺序、拖带和舒张期电位仍然有价值,而非接触式标测等新技术提供了较强大的标测手段。然而,消融的能量和效能仍然是制约成功率的主要因素。心外膜标测、盐水冲洗大头和冷凝消融具有潜在的价值。     

器质性心脏病室性心动过速导管消融治疗进展

器质性心脏病瘢痕相关性室性心动过速（室速）的发生主要是折返机制,目前多采用心脏三维标测系统指引下对耐受性好、血流动力学稳定的室速激动标测消融,对于血流动力学不稳定的室速,窦性心律下基质标测、电压图判断室速的解剖基质,结合起搏标测和拖带标测技术识别室速的折返环,盐水灌注导管消融治疗;近年来不断积累有关临床循证证据、适应证进一步拓展、新的标测消融和辅助技术临床上应用,取得了新的进展。     

非接触标测在室性心动过速消融中的应用

非接触球囊标测系统以其独有的优势展现了全新的电生理标测方法,在多种心律失常的消融过程中,扮演着重要角色,尤其是室性心律失常的消融,现对非接触球囊标测系统的特点及在室性心动过速消融中的作用分别总结和叙述。     

特发性室性心动过速的射频消融

目的:对经射频消融术证实的特发性室性心动过速的病例进行总结分析,探讨室性心动过速的发病状况、心电图特点、消融靶点的确定及消融结果。方法:对68 例特发性室性心动过速的起源部位和体表心电图进行分析,所有患者在诱发出室性心动过速后进行射频消融治疗,观察特发性室性心动过速的射频消融成功率和复发率以及它们和消融靶点的关系。结果:本组特发性室性心动过速患者中右室室性心动过速较左室室性心动过速多见。右室特发性室性心动过速心电图表现为左束支传导阻滞,左室特发性室性心动过速心电图则多表现为右束支传导阻滞。消融靶点的确定右室特发性室性心动过速主要采用起搏标测法,左室特发性室性心动过速主要采用激动顺序标测法。右室流出道室速组在起搏标测时起搏ECG和VT时ECG的12导联QRS波完全相同处消融成功率较高。结论:室性心动过速发作时的体表心电图可初步估计特发性室性心动过速的起源部位,射频消融术治疗特发性室性心动过速成功率高,并发症少。     

Radiofrequency Catheter Ablation of Idiopathic Left Ventricular Tachycardia:

Idiopathic Left Ventricular Tachycardia. Introduction: Idiopathic left ventricular tachycardia with a QRS pattern of right bundle branch block and left-axis deviation constitutes a rare but electrophysiologically distinct arrhythmia entity. The underlying mechanism of this tachycardia, however, is still a matter of controversy. This report describes findings in a 42-year-old man who underwent successful radiofrequency catheter ablation of idiopathic left ventricular tachycardia.
Methods and Results: On electrophysiologic study, the tachycardia was reproducibly induced and terminated with double ventricular extrastimuli. Intravenous verapamil terminated the tachycardia whereas adenosine did not. Detailed left ventricular catheter mapping during sinus rhythm revealed a fragmented delayed potential at the mid-apical region of the inferior site near the posterior fascicle of the left bundle branch. At the same site, continuous electrical activity throughout the entire cardiac cycle was recorded during ventricular tachycardia. Repeated spontaneous termination of this continuous electrical activity in late diastole was followed immediately by termination of the tachycardia. Single application of radiofrequency current for 20 seconds at this site completely abolished inducibility of the tachycardia. After catheter ablation, at the identical site of preablation recording of the fractionated potential during sinus rhythm, no fragmented delayed activity could be recorded. There was no complication from the ablation procedure.
Conclusion: The preablation recordings of fragmented delayed potentials during sinus rhythm and continuous diastolic electrical activity during tachycardia, together with ablation characteristics and previously reported electrophysiologic properties of this arrhythmia, may further support microreentry as the underlying mechanism in idiopathic left ventricular tachycardia.     

Ablation of Idiopathic Right Ventricular Outflow Tract Tachycardia: Current Perspectives

Ventricular tachycardia (VT) arising from the right ventricular outflow tract (RVOT) in the absence of overt structural heart disease is a common entity. Exclusion of occult structural disease such as arrhythmogenic right ventricular cardiomyopathy is critical as this diagnosis impacts both ablation outcomes and long-term prognosis. VT is most commonly due to triggered activity. Induction of the target arrhythmia in the laboratory is often problematic, and is frequently facilitated by catecholamine infusion. Recent data indicate that high-density three-dimensional activation mapping facilitates identification of target sites for ablation, and that the spatial resolution of pacemapping may be more limited than previously recognized. A standard 12-lead electrocardiogram is useful in providing an initial approximation of the site of origin within the outflow tract, and may contain subtle clues to potentially confounding foci on the left ventricular endocardial or epicardial surface. When sufficient arrhythmia is present to permit mapping, successful ablation can be expected in 90–95% of patients, with a recurrence risk of approximately 5%. In experienced centers, major complications are ≤1% and outcomes should approach those obtained for the common forms of supraventricular tachycardia.     

Anterior Q-Wave Infarction Complicating Attempted Catheter Electrode Ablation of Ventricular Tachycardia

This report describes an attempt to treat recurrent ventricular tachycardia by catheter electrode ablation. The procedure failed to control the arrhythmia and resulted in a Q-wave anteroseptal myocardial infarction. The potential complications of catheter electrode ablation in the normal ventricle are emphasized.     

Catheter Ablation of Repetitive Monomorphic Ventricular Tachycardia From Left Ventricular Outflow Tract Guided by Unipolar Mapping

Repetitive monomorphic ventricular tachycardia from the left ventricular outflow tract is an uncommon arrhythmia. Successful catheter ablation has been previously reported in a few cases, but a large number of applications were usually needed when an approach based on either activation mapping or pace mapping was used. In our patient, the selection of the target point for application was based exclusively on unipolar mapping criteria of the ectopic beats, resulting in a short procedure with successful outcome.     

Strategies for Epicardial Mapping and Ablation of Ventricular Tachycardia

Catheter ablation for ventricular tachycardia (VT) is becoming an essential component of the successful management of patients with structural heart disease and refractory ventricular arrhythmias. Despite detailed mapping and ablation from the endocardium, nearly a third of VT circuits remain inaccessible. Pericardial access has improved our ability to address these resistant VTs. Adhesions after cardiac surgery can impede access, necessitating a direct surgical approach to the pericardial space. Potential risks include risk of injury to an epicardial coronary artery, the phrenic nerve, subdiaphragmatic vessels, and right ventricle. We describe the indications for and approach to catheter ablation of VT for the pericardial space.     

Radiofrequency Catheter Ablation of Idiopathic Left Ventricular Tachycardia Originating in Both Left Posterior and Anterior Fascicles

A 45-year-old woman underwent radiofrequency ablation (RFA) for symptomatic idiopathic left ventricular tachycardia (ILVT). The clinical arrhythmias had two different patterns, a wide QRS tachycardia with right bundle branch block (RBBB) and left axis deviation (LAD) and another with RBBB and right axis deviation (RAD). The electrophysiology study localized the origin of tachycardias to the midinferior and superior ventricular septum, respectively. RFA terminated successfully ILVT with RBBB and LAD morphology, but another pattern could not be ablated. Noncontact mapping revealed the earliest site of activation at the superior septum. RFA at this site terminated successfully ILVT with RBBB and RAD.     

Robotic Catheter Ablation of Ventricular Tachycardia in a Patient with Congenital Heart Disease and Rastelli Repair

Robotically assisted catheter ablation has been proven feasible in patients with a variety of atrial arrhythmias. The potential to provide improved catheter tip maneuvering and stability potentially makes it ideal for complex ablation procedures. We present the case of a patient with complex congenital heart disease with previous Rastelli repair and recurrent ventricular tachycardia (VT) who underwent robotically assisted mapping and ablation for right ventricular VT, utilizing substrate mapping techniques.     

Ablation of Ventricular Tachycardia with a Saline-Cooled Radiofrequency Catheter:

INTRODUCTION: In animal models, active cooling of the electrode during radiofrequency (RF) ablation allows creation of larger lesions, presumably by increasing the power that can be delivered without coagulum formation. These RF lesions have not been characterized in human myocardium in regions of infarction and scarring. METHODS AND RESULTS: Cooled-tip RF catheter ablation of ventricular tachycardias (VTs) was performed in two patients who had severe congestive heart failure and subsequently underwent cardiac transplantation. The first patient had four different monomorphic VTs. RF applications along the inferoseptal margin of a scarred region abolished all inducible VTs. The second patient had sarcoidosis involving the myocardium and four different inducible VTs. RF current applied at an inferobasal VT exit and at the right and left septa failed to abolish the VTs. The explanted hearts were examined at the time of cardiac transplantation 18 and 21 days later, respectively. Lesions extended to depths up to 7 mm, reaching clusters of myocardial cells deep to regions of fibrosis. Microscopically, the ablation sites contained coagulation necrosis with hemorrhage, surrounded by a rim of granulation tissue. CONCLUSION: Saline-irrigated RF catheter ablation produces relatively large lesions capable of penetrating deep into scarred myocardium.     

Management of Ventricular Tachycardia in Heart Failure

Ventricular tachyarrhythmias are common in patients with congestive heart failure. The clinical presentation ranges from an asymptomatic incidental electrocardiographic finding to palpitations, syncope, and sudden cardiac death. Although implantable cardioverter defibrillators successfully prevent sudden cardiac death associated with ventricular fibrillation and ventricular tachycardia, recurrent implantable cardioverter defibrillators shocks remain a clinical management challenge. In this review, we discuss management strategies of ventricular tachycardia in congestive heart failure, including drug therapy, radiofrequency catheter ablation (RFCA), and recent RFCA advances.     

Comparison of Presystolic Purkinje and Late Diastolic Potentials for Selection of Ablation Site in Idiopathic Verapamil Sensitive Left Ventricular Tachycardia

BACKGROUND: Idiopathic verapamil-sensitive left ventricular tachycardia (ILVT) is the most common form of idiopathic left ventricular tachycardia (VT). Different methods have been proposed for ablation of ILVT. METHODS: Between June 2002 and February 2004, 15 patients (12 men; age 28 +/- 11 years, range 12 to 51) with ILVT underwent radiofrequency (RF) ablation at our center. We retrospectively assessed the significance of recording purkinje potential (PP) and late diastolic potential (DP) and its effect on selection of ablation target and number of RF application. RESULTS: Sixteen VTs were observed. The clinical VT had either RBBB and left axis morphology (14 cases) or RBBB and right axis morphology (2 cases). The QRS duration during tachycardia was 124 +/- 12 ms and the tachycardia cycle length was 356 +/- 53 ms. DP and PP were recorded at the targeted area for RF ablation in 11 and 9 patients respectively. The PP-Q interval, DP-Q interval and DP width were 18 +/- 4, 53 +/- 18 and 14 +/- 8 ms, respectively. The number of RF application was 7.2 +/- 4.3. Fewer applications were needed in whom RF ablation was initially targeted to PP (with or without DP) recording site (10 patients, 4.7 +/- 1.8) compared to those targeted to DP recording site (5 patients, 12.2 +/- 3.3) ( P < 0.05). CONCLUSION: Compared to DP alone, earliest PP (with or without concomitant DP) might be superior for selection of target site of RF ablation in patients with ILVT.     

Catheter Ablation of Idiopathic Ventricular Tachycardia Arising from the Aortic Root

Most idiopathic ventricular tachycardia (VT) arises from the area of the outflow tracts, and the most common left ventricular site is the aortic root, usually from the right and left sinuses of Valsalva. This site of origin is suggested by specific patterns on the electrocardiogram. Activation mapping and pace mapping are both useful strategies, and their relative benefits and limitations need to be appreciated. The mapping strategy for a VT of suspected aortic root origin is based on the consideration that multiple chambers may need to be mapped, and the temptation to ablate at suboptimal sites based on the justification that it was easy to get to should be resisted. The entire surface of each cusp needs to be sampled, as distinct activation times and pacemaps are obtained at each site. Standard radiofrequency energy is typically adequate and the precision of mapping rather than the amount of tissue ablated is tantamount to success. In my opinion, the indications for ablation of aortic root VT are similar to those for other idiopathic VT. Although I offer patients both pharmacologic and nonpharmacologic options, I feel that ablation is first line therapy for patients with sufficient symptoms to warrant therapy.     

Radiofrequency Catheter Ablation of Sustained Monomorphic Ventricular Tachycardia in Hypertrophic Cardiomyopathy

Monomorphic VT in HCM. Introduction : Incessant monomorphic ventricular tachycardia (VT) with a right bundle branch block morphology and a northwest axis is a rare arrhythmic complication in a patient with hypertrophic cardiomyopathy and apical left ventricular aneurysm.
Methods and Results : The origin of this VT was localized using the following criteria: the presence of entrainment without fusion, equal internals from the stimulus to the beginning of the QRS complex and from the electrogram to the QRS complex during VT, and the first postpacing interval identical to the tachycardia cycle length. Radiofrequency energy applied to the septoapical part of the apical left ventricular aneurysm terminated the tachycardia within 2 seconds.
Conclusion : Using criteria to guide radiofrequency (RF) ablation of VT in patients with coronary artery disease, an incessant monomorphic VT in a patient with hypertrophic cardiomyopathy was successfully ablated.     

Endocardial and Epicardial Ablation Guided by Nonsurgical Transthoracic Epicardial Mapping to Treat Recurrent Ventricular Tachycardia

Nonsurgical Epicardial Ablation. Introduction : An epicardial site of origin of ventricular tachycardia (VT) may explain unsuccessful endocardial radiofrequency (RF) catheter ablation. A new technique to map the epicardial surface of the heart through pericardial puncture was presented recently and opened the possibility of using epicardial mapping to guide endocardial ablation or epicardial catheter ablation. We report the efficacy and safety of these two approaches to treat 10 consecutive patients with VT and Chagas' disease.
Methods and Results : Epicardial mapping was carried out with a regular steerable catheter introduced into the pericardial space. An epicardial circuit was found in 14 of 18 mapable VTs induced in 10 patients. Epicardial mapping was used to guide endocardial ablation in 4 patients and epicardial ablation in 6. The epicardial earliest activation site occurred 107 ± 60 msec earlier than the onset of the QRS complex. At the epicardial site used to guide endocardial ablation, earliest activation occurred 75 ± 55 msec before the QRS complex. Epicardial mid-diastolic potentials and/or continuous electrical activity were seen in 7 patients. After 4.8 ± 2.9 seconds of epicardial RF applications, VT was rendered noninducible. Hemopericardium requiring drainage occurred in 1 patient; 3 others developed pericardial friction without hemopericardium. Patients remain asymptomatic 5 to 9 months after the procedure. Interruption during endocardial pulses occurred after 20.2 ± 14 seconds (P = 0.004), hut VT was always reinducible and the patients experienced a poor outcome.
Conclusion : Epicardial mapping does not enhance the effectiveness of endocardial pulses of RF. Epicardial applications of RF energy can safely and effectively treat patients with VT and Chagas' disease.