Left posterior fascicular tachycardia due to localized microreentry

Fascicular tachycardia in young patients without overt heart disease constitutes a rare but electrophysiologically distinct arrhythmia entity. Microreentry within the left posterior fascicle has been proposed as its mechanism, but evidence for this is inconclusive. This report details a patient with incessant fascicular tachycardia. The electrophysiological features, in particular the pattern of resetting response, provided strong evidence for reentry as the tachycardia mechanism. Satisfactory long-term arrhythmia control was achieved with flecainide.     

Long‐Term Outcome After Catheter Ablation for Left Posterior Fascicular Ventricular Tachycardia Without Development of Left Posterior Fascicular Block

Long‐Term Outcome After Substrate‐Based Ablation of LPF VT During SR . Background: Catheter ablation of left posterior fascicular (LPF) ventricular tachycardia (VT) is commonly performed during tachycardia. This study reports on the long‐term outcome of patients undergoing ablation of LPF VT targeting the earliest retrograde activation within the posterior Purkinje fiber network during sinus rhythm (SR). Methods: This study retrospectively analyzed 24 consecutive patients (8 female; mean age 26 ± 11 years) referred for catheter ablation of electrocardiographically documented LPF VT. Programmed stimulation was performed to induce tachycardia, while mapping and ablation was aided by use of a 3D electroanatomical mapping system. Catheter ablation targeted the earliest potential suggestive of retrograde activation within the posterior Purkinje fiber network (retro‐PP) recorded along the posterior mid‐septal left ventricle during SR if LPF VT was noninducible. Results: Overall, 21/24 (87.5%) patients underwent successful catheter ablation in SR targeting the earliest retro‐PP, while 3/24 (12.5%) patients were successfully ablated during tachycardia. In none of the patients, ablation resulted in LPF block. No procedure‐related complications occurred. After a median follow‐up period of 8.9 (4.8–10.9) years, 22/24 (92%) patients were free from recurrent VT. Conclusion: In patients presenting with LPF VT, ablation of the earliest retro‐PP along the posterior mid‐septal LV during SR results in excellent long‐term outcome during a median follow‐up period of almost 9 years. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1179–1184, November 2012)     

Diagnosis and Ablation of Multiform Fascicular Tachycardia

Ablation Multiform Fascicular Tachycardia . Introduction: Fascicular tachycardia (FT) is an uncommon cause of monomorphic sustained ventricular tachycardia (VT). We describe 6 cases of FT with multiform QRS morphologies. Methods and Results : Six of 823 consecutive VT cases were retrospectively analyzed and found attributable to FT with multiform QRS patterns, with 3 cases exhibiting narrow QRS VT as well. All underwent electrophysiology study including fascicular potential mapping, entrainment pacing, and electroanatomic mapping. The first 3 cases describe similar multiform VT patterns with successful ablation in the upper mid septum. Initially, a right bundle branch block (RBBB) VT with superior axis was induced. Radiofrequency catheter ablation (RFCA) targeting the left posterior fascicle (LPF) resulted in a second VT with RBBB inferior axis. RFCA in the upper septum just apical to the LBB potential abolished VT in all cases. Cases 4 and 5 showed RBBB VT with alternating fascicular block compatible with upper septal dependent VT, resulting in bundle branch reentrant VT (BBRT) after ablation of LPF and left anterior fascicle (LAF). Finally, Cases 5 and 6 demonstrated spontaneous shift in QRS morphology during VT, implicating participation of a third fascicle. In Case 6, successful ablation was achieved over the proximal LAF, likely representing insertion of the auxiliary fascicle near the proximal LAF. Conclusions : Multiform FTs show a reentrant mechanism using multiple fascicular branches. We hypothesize that retrograde conduction over the septal fascicle produces alternate fascicular patterns as well as narrow VT forms. Ablation of the respective fascicle was successful in abolishing FT but does not preclude development of BBRT unless septal fascicle is targeted and ablated. (J Cardiovasc Electrophysiol, Vol. 24, pp. 297‐304, March 2013)     

伴连续性房室结功能曲线的房室结折返性心动过速的电生理分析

目的：探讨无房室结双径路特性的房室结折返性心动过速(AVNRT)的电生理特点。方法：所有心动过速患射频消融前常规行心内电生理检查。结果：845例射频病人中325例为AVNRT，其中有21例患房室结功能曲线呈连续性，其电生理特征：希氏束图上心房回波(A)先出现，A波落在室波升支或其前，希氏柬不应期内刺激心室，不能提前夺获心房，射频消融后心房刺激时AHmax明显缩短。结论：伴连续性房室结功能曲线的AVNRT患心房刺激不表现房室结双径路的电生理特性，其消融终点初步定为：心房心室S1S1、S1S2刺激不诱发AVNRT；无AHvH传导曲线跳跃；房室结前传不应期明显缩短。     

Radiofrequency catheter ablation for atrial tachycardia originating from the left atrial appendage

A 36-year-old woman presented with drug-refractory atrial tachycardia. During the tachycardia episodes, P waves were positive in leads II, III, aVF, and V1, while they were negative in leads I and aVL. It was hard to determine whether the origin was the left atrial appendage or left superior pulmonary vein on the surface electrocardiogram. Electrophysiologic evaluation revealed that the earliest endocardial activation occurred at the base of the left atrial appendage, preceding the onset of P waves by 38 ms. On initiation of the tachycardia, a warm-up phenomenon was observed. There was a fixed relation between the coupling interval of a single extrastimulus and the return cycle length during the tachycardia. These findings suggested that the mechanism of the tachycardia was automaticity. Application of radiofrequency energy at the left atrial appendage terminated the tachycardia and it was not inducible after ablation.     

Macroreentrant atrial tachycardia with an isolated pathway mimicking focal activation on three-dimensional electroanatomical mapping

A 76-year-old man with two different sustained atrial arrhythmias that occurred after coronary artery bypass grafting underwent electrophysiological studies. Macroreentrant atrial tachycardias were detected with an isolated slow pathway mimicking focal activation on three-dimensional electroanatomical mapping. The slow conduction pathway in the right atrial free wall was assumed to represent tissue damaged by right atrial cannulation during previous coronary artery bypass grafting.     

A novel pacing maneuver to verify the postpacing interval minus the tachycardia cycle length while adjusting for decremental conduction: Using “dual-chamber entrainment” for improved supraventricular tachycardia discrimination

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Bundle-Branch reentry tachycardia

A 21-year-old man with aborted sudden death developed bundle-branch reentry tachycardia at electrophysiologic study. Ablation of the right bundle branch was performed in an attempt to eliminate the recurrence of ventricular arrhythmia. The clinical arrhythmia was no longer inducible; however, a second type of ventricular tachycardia of a different mechanism and origin was induced. Following a new clinical episode of ventricular tachycardia with hemodynamic deterioration, an automatic implantable cardioverter and defibrillator was implanted.     

Tachycardia induced tachycardia: case report of right ventricular outflow tract tachycardia and AV nodal reentrant tachycardia

Tachycardia induced tachycardia, or so called double tachycardia, is rare. A 34 year old woman is described who had a history of syncope, frequent extrasystoles, and episodes of non-sustained ventricular tachycardia, perceived as palpitation, without syncope. At electrophysiological study, during infusion of isoprenaline, an episode of non-sustained ventricular tachycardia arising from the right ventricular outflow tract initiated sustained atrioventricular nodal reentrant tachycardia, thought to be the cause of the patient's syncope. Ablation of the right ventricular outflow tract focus abolished the ventricular ectopy; the slow AV nodal pathway was also ablated. The patient no longer has either syncope or palpitation.     

Radiofrequency Ablation of Idiopathic Left Anterior Fascicular Tachycardia

Left Anterior Fascicular Tachycardia. Introduction: A 45-year-old man with idiopathic ventricular tachycardia (VT) having a right bundle branch block configuration with right-axis deviation underwent au electrophysiologic test.
Methods and Results: Mapping demonstrated a site on the auterobasal wall of the left ventricle where there was an excellent pace map and an endocardial activation time of -20 msec, hut radiofrequency catheter ablation at this site was unsuccessful. At a nearby site, a presumed Purkinje potential preceded the QRS complex by 30 msec during VT and sinus rhythm, and catheter ablation was effective despite a poor pace map and an endocardial ventricular activation time of zero.
Conclusion: Idiopathic VT with a right bundle branch configuration and right-axis deviation may originate in the area of the left anterior fascicle. A potential presumed to represent a Purkinje potential may he more helpful than endocardial ventricular activation mapping or pace mapping in guiding ablation of this type of VT.     

Syncopal monomorphic ventricular tachycardia with pleomorphism, sensitive to antitachycardia pacing in a patient with Brugada syndrome.

Polymorphic ventricular tachycardia and ventricular fibrillation are the most common arrhythmias in Brugada syndrome, causing syncope or sudden death. Sustained monomorphic ventricular tachycardias are rare in this context. We report the case of a 41-year-old man with repetitive syncopal episodes and an ajmaline-induced characteristic Brugada ECG pattern, in whom episodes of monomorphic ventricular tachycardia with pleomorphism and response to ventricular pacing were documented.     

32例分支型室性心动过速的诊断和治疗探讨

目的:探讨分支型室性心动过速(FVT)的诊断和治疗方法。方法:回顾性分析32例FVT的临床资料、心电图、食管及心内电生理特点。结果:FVT可根据心电图、食管及心内电生理确诊,急性发作时可采用药物控制,应用导管射频消融术(RFCA)可根治。结论:FVT可根据ECG资料迅速、准确作出诊断,RFCA根治FVT有效且安全。     

急性心肌梗死非持续和持续室性心动过速的Q—T离散度

为研究急眭心肌梗死伴持续和非持续室性心动过速患者间Q-T离散度和其它心电图参数之间的关系。比较14例急性心肌梗死伴持续室性心动过速和26例伴非持续室性心动过速患者的心室Q-T离散度、Q-T和Q-T_c间期。结果显示持续和非持续室性心动过速患者之间的Q-T离散度以及相邻胸导联Q-T离散度差异有显著意义(110.1±7.80对80.8±4.4,105.9±6.9对67.6±4.0,P<0.01)。我们认为相邻导联Q-T离散度增大极易出现室性心动过速,Q-T离散度大于110ms有发生持续室性心动过速的危险。而Q-T离散度在80—110ms之间有非持续室性心动过速的可能性。     

Ectopic ventricular tachycardia sensitive to calcium antagonists in acute myocardial infarction in dogs

The effects of antiarrhythmic agents on automatic ventricular tachycardia (VT), which emerged in the early stage of acute myocardial infarction (AMI), were examined in 30 closed-chest mongrel dogs. Antiarrhythmic agents were administered intravenously when the rate of VT became almost equal to sinus rate (5.6 +/- 1.4 hours). VT was slowed significantly by verapamil (0.15 or 0.3 mg/kg), diltiazem (0.2 or 0.4 mg/kg), propranolol (0.1 mg/kg) and amiodarone (5 mg/kg), but not by procainamide (20 mg/kg), lidocaine (2 or 4 mg/kg), nifedipine (0.01 mg/kg) and nicorandil (0.03 mg/kg). The number of ventricular premature complexes was reduced most effectively by verapamil. The significant suppressive effects of calcium antagonist drugs (verapamil and diltiazem) and propranolol indicate that an inward calcium current during diastole may play a critical role in the abnormal enhancement of ventricular automaticity in the early stage (4 to 8 hours) of AMI.     

Ventricular tachycardia: Newer insights

Electrophysiology has provided insights into our understanding of ventricular tachycardia. The techniques of electrophysiology which were useful as a research tool have only recently come to be appreciated in clinical practice. As a result, we have expanded our knowledge of the mechanisms of ventricular arrhythmias; we can distinguish among tachycardias masquerading as ventricular tachycardia; we can predict the response to drug and pacemaker treatment, and we can select out those who require surgical management.     

Idiopathic verapamil-sensitive sustained left ventricular tachycardia

Idiopathic verapamil-sensitive left ventricular tachycardia (VT) has characteristic QRS configurations during VT: right bundle-branch block with either left axis or right axis (less common) deviation. QRS duration is relatively narrow (0.13-0.16s) and frequently endocardial activation prior to QRS is recorded during VT, which is the basis of its being called fascicular tachycardia. The mechanism is probably reentry, but the nature of the slow conduction necessary for the occurrence of reentry is quite different from that of other sustained monomorphic VT associated with structural heart disease. Chronic oral verapamil therapy is the drug of choice for alleviation of symptoms. Long-term prognosis is good.