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.     

Atrial Tachycardia Originating from a Single Site with Exit Block Mimicking Atrial Fibrillation Eliminated with Radiofrequency Applications

Atrial Tachycardia from a Single Site. We describe the case of a patient who has a right atrial tachycardia and atrial fibrillation who was found to have a single site responsible for both. We recorded a tachycardia from this site with exit block into the remainder of the atria.     

DDD-Pacing-Induced Cardiomyopathy Following AV Node Ablation for Persistent Atrial Tachycardia

Ventricular rate control by catheter ablation of the AV node and pacing in patients with persistent atrial tachycardia has been reported to improve left ventricular function. However, this approach requires careful selection of the pacing mode. We report a patient who underwent AV node ablation for persistent multiple atrial tachycardias, and who then had a non-mode-switching pacemaker implanted. Because of an inappropriately programmed relatively high upper rate limit, the patient developed left ventricular dysfunction after 6 years. This resolved after programming the pacemaker to VVI at 70 bpm.     

Radiofrequency Catheter Ablation in Unusual Mechanisms of Atrial Fibrillation:

RF Catheter Ablation in AF. Introduction: The purpose of this study was to test the feasibility of radiofrequency (RF) catheter ablation of localized mechanisms of atrial fibrillation (AF).
Methods and Results: Three patients underwent RF catheter ablation for drug-resistant atrial arrhythmias. The first two patients had either incessant atrial tachycardia or AF. In the first patient, the KCG pattern of AF was mimicked by a very rapid atrial focus, whereas in the second patient, AF was due to true degeneration of the atrial activity triggered by atrial tachycardia. In both patients, the ablation of atrial focus led to the clinical disappearance of AF. The third patient had frequent episodes of AF, which lasted several days or weeks, and two documented episodes of atrial flutter. Mapping during AF showed an irregular atrial rhythm in the atrial septum, particularly in the region surrounding the coronary sinus, whereas the entire lateral right atrial free wall exhibited a constantly organized rhythm. RF energy was applied between the tricuspid ring and both the inferior vena cava and the coronary sinus, resulting in inability to reinduceatrial flutter or sustained AF. A 6-month follow-up in this patient showed the disappearance of prolonged episodes of AF.
Conclusion: The observations indicate that AF may be linked to "focal" mechanisms that can be treated by RF catheter ablation.     

Radiofrequency Catheter Ablation of Ventricular Tachycardia in Right Ventricular Cardiomyopathy:

RF Catheter Ablation of VT. Radiofrequency (RF) catheter ablation of ventricular tachycardia (VT) in patients with a right ventricular (RV) cardiomyopathy has only rarely been successful. This report demonstrates reentrant VT in the setting of RV cardiomyopathy in which the tricuspid valve annulus acted as one of the harriers of an isthmus of slow conduction, identified by the presence of entrainment with concealed fusion. The RF pulse was further targeted by analysis of the relationship between the postpacing interval with the tachycardia cycle length, and of the local activation time with the stimulation time. Long-term clinical follow-up has documented no recurrent VT.     

Long‐Term Outcome Following Successful Catheter Ablation of Atrial Tachycardia Originating From the Pulmonary Veins: Absence of Late Atrial Fibrillation

Atrial Fibrillation and Pulmonary Vein Tachycardia . Objectives: This study aimed to characterize the long‐term outcome and incidence of atrial fibrillation (AF) in patients following catheter ablation of focal atrial tachycardia (AT) from the pulmonary veins (PV). Background: Although both AT and AF may originate from ectopic foci within PVs, it is unknown whether PV AT patients subsequently develop AF. Methods: Twenty‐eight patients with 29 PV ATs (14%) from a consecutive series of 194 patients who underwent RFA for focal AT were included. Patients with concomitant AF prior to the index procedure were excluded. Results: The minimum follow‐up duration was 4 years; mean age 38 ± 18 years with symptoms for 6.5 ± 10 years, having tried 1.5 ± 0.9 antiarrhythmic drugs. The distribution of foci was: left superior 12 (41%), right superior 10 (34%), left inferior 5 (17%), and right inferior 2 (7%). The focus was ostial in 93% and 2–4 cm distally within the vein in 7%. Mean tachycardia cycle length was 364 ± 90 ms. Focal ablation was performed in 25 of 28 patients. There were 6 recurrences with 5 from the original site. Twenty‐six patients were available for long‐term clinical follow‐up. At a mean of 7.2 ± 2.1 years, 25 of 26 (96%) were free from recurrence off antiarrhythmic drugs. No patients developed AF. Conclusions: Focal ablation for tachycardia originating from the PVs is associated with long‐term freedom from both AT and AF. Therefore, although PV AT and PV AF share a common anatomic distribution, PV AT is a distinct clinical entity successfully treated with focal RFA and not associated with AF in the long term. (J Cardiovasc Electrophysiol, Vol. pp. 747‐750, July 2010)     

Electroanatomical Mapping and Radiofrequency Catheter Ablation of Atrial Tachycardia Originating from the Recipient Heart with Recipient-to-Donor Atrio-Atrial Conduction After Orthotopic Heart Transplantation

Atrial tachycardias resulting from recipient-to-donor atrio-atrial conduction after orthotopic heart transplantation are difficult to treat. We present two patients in whom atrial tachycardia originating in the recipient heart were successfully treated by radiofrequency ablation guided by electroanatomical CARTO mapping system. These cases illustrate that such atrial tachycardia are curable by radiofrequency ablation. Electroanatomical CARTO mapping is useful in identifying the site of origin of the tachycardia and the atrio-atrial conduction sites.     

房室折返性心动过速合并阵发性心房颤动的射频导管消融策略

目的探讨房室折返性心动过速（AVRT）合并阵发性心房颤动的射频导管消融（下称消融）策略。方法对经电生理检查证实的AVRT患者15例行旁道消融术,其中男性9例,女性6例,并对术后心房颤动的转归进行12～36个月的随访,观察心房颤动发生、持续时间、有无心律失常等情况。结果13例未再发生心房颤动,2例有严重器质性心脏病的患者仍有阵发性心房颤动复发,但发作次数明显减少,口服胺碘酮可控制症状。1例动态心电图示频发房性期前收缩。结论AVRT与阵发性心房颤动发生率增高密切相关,AVRT是心房颤动的触发因素。旁道消融后,阵发性心房颤动可明显改善,未改善者与心房扩大等心房基质未改善有关。     

A Seven-year Experience for The Surgical Radiofrequency Ablation in Patients With Atrial Fibrillation

Objective A 7-year experience for the treatment strategy using mono- and bi-polar radiofrequency （RF） ablation procedures in a heterogeneous group of patients was reported. Methods Between July 2003 and May 2009, the data of 314 consecutive patients aged 13 -75 （48.70 ± 11.09 ）undergone the radiofrequency ablation procedure for atrial fibrillation （AF） associated with concomitant cardiac surgery were analyzed. Monopolar was used for 91 patients; Medtronic bi-polar RF ablation procedure for 92 patients and Atricure RF ablation procedure for 131 patients. All patients were combined with valve surgery. Regular follow-ups were performed at 3, 6 month after surgery. Results Hospital mortality after combined open heart and surgical RF ablation was 0 %. The success rates for sinus rhythm conversion with monopolar RF were 73.6 % immediately, 74. 7 % at 3 months, 79. 1% at 6 months ; with Medtronic bi- polar RF, the rates were 78.3 % immediately, 82. 8 % at 3 months, 84 % at 6 months ; with Atricure bi-polar RF, the rates were 82. 4 % immediately, 84. 1% at 3 months, 83.9 % at 6 months. Conclusions The use of RF ablation procedures is a safe and efficient option to cure AF during open heart surgery in a selective group of patients.     

Post-Pericardiotomy Syndrome Following Linear Left Atrial Radiofrequency Ablation

Post-pericardiotomy syndrome may occur after traumatic insults to the pericardium but has not been reported after radiofrequency catheter (RF) ablation. A 54 year old man underwent extensive linear left atrial RF ablation for chronic atrial fibrillation. Five days after the procedure the patient developed signs and symptoms of the post-pericardiotomy syndrome and showed new, intense pericardial inflammation on magnetic resonance imaging. After intensive medical management, the patient recovered fully. It is believed that the patient experienced a unique complication of linear left atrial ablation, i.e., post-pericardiotomy syndrome due to extensive left atrial necrosis or direct thermal pericardial injury.     

Tachycardia-Induced Cardiomyopathy Secondary to Right Ventricular Outflow Tract Ventricular Tachycardia: Improvement of Left Ventricular Systolic Function After Radiofrequency Catheter Ablation of the Arrhythmia

Cardiomyopathy Secondary to RVOT VT. Introduction : Several reports describe development of cardiomyopathics secondary to supraventricular tachycardia. Few reports have described cardiomyopathies secondary to ventricular tachycardia.
Methods and Results : We describe a patient who presented with dilated cardiomyopathy and repetitive nonsustained monomorphic ventricular tachycardia. Cardiac cathcterization showed hemodynamically insignificant coronary artery disease. Radiofrequency ablation of a right ventricular outflow tract ventricular tachycardia resulted in improvement of the left ventricular systolic function and resolution of heart failure symptoms.
Conclusions : This report suggests that right ventricular outflow tract ventricular tachycardia may cause reversible tachycardia-induced cardiomyopathy.     

Electrogram-Guided Radiofrequency Catheter Ablation of Atrial Tissue Comparison with Thermometry-Guide Ablation

Objectives: To characterize a new method for radiofrequency energy titration during ablation of atrial tissue based on reduction in electrogram amplitude. To compare this method with energy titration using electrode thermometry. Background: Complications associated with anatomy-based atrial endocardial radiofrequency ablation for suppression of atrial fibrillation may be due to flawed methods of energy titration. Methods: The effect of radiofrequency ablation on electrogram amplitude was characterized in a porcine model. A method for energy titration guided by electrogram amplitude reduction (electrogram-guided) was developed and validated prospectively. Focal (smooth and trabeculated endocardial areas) and linear (smooth endocardial areas) ablation was performed comparing energy titration guided by amplitude reduction with electrode thermometry. Results: Amplitude reduction during radiofrequency application was not necessarily equal among unipolar and bipolar electrograms in the ablation region; specific patterns of reduction could be discerned, based on factors such as catheter-endocardial orientation. A criterion of >90% reduction of unipolar and/or bipolar amplitude best predicted pathologic lesion success. Electrogram-guided focal and linear lesions in smooth areas were free of lesion complications such as endocardial charring, barotrauma, or damage to contiguous extraatrial structures. However, there was a significant incidence of insufficient lesion size, principally non-transmurality, probably due to undertitration of energy. Thermometry-guided focal and linear lesions in smooth areas were uniformly transmural but frequently evidenced complications, due to overtitration of energy. Electrogram-guided focal lesions in trabeculated areas could usually not be achieved, probably due to insufficient contact of the ablation electrode with adjacent pectinate muscles. Thermometry-guided focal lesions in trabeculated areas were smaller than electrogram-guided lesions and did not evidence complications. Conclusions: Electrogram-guided lesions in smooth endocardial areas were uncomplicated but had a significant incidence of non-transmurality. Thermometry-guided lesions were uniformly transmural but were frequently complicated.     

Clinical Significance of Early Recurrences of Atrial Tachycardia After Atrial Fibrillation Ablation

Early Recurrence After AF Ablation. Background: Atrial tachycardia (AT) commonly recurs within 3 months after radiofrequency catheter ablation for atrial fibrillation (AF). However, it remains unclear whether early recurrence of atrial tachycardia (ERAT) predicts late recurrence of AF or AT. Methods: Of 352 consecutive patients who underwent circumferential pulmonary vein isolation with or without linear ablation(s) for AF, 56 patients (15.9%) with ERAT were identified by retrospective analysis. ERAT was defined as early relapse of AT within a 3‐month blanking period after ablation. Results: During 21.7 ± 12.5 months, the rate of late recurrence was higher in patients with ERAT (41.1%) compared with those without ERAT (11.8%, P < 0.001). In a multivariable model, positive inducibility of AF or AT immediately after ablation (65.2% vs 36.4%, P = 0.046; odd ratio, 3.9; 95% confidence interval, 1.0–14.6) and the number of patients who underwent cavotricuspid isthmus (CTI) ablation (73.9% vs 42.4%, P = 0.042; odd ratio, 4.5; 95% confidence interval, 1.1–19.5) were significantly related to late recurrence in the ERAT group. The duration of ablation (174.3 ± 62.3 vs 114.7 ± 39.5 minutes, P = 0.046) and the procedure time (329.3 ± 83.4 vs 279.2 ± 79.7 minutes, P = 0.027) were significantly longer in patients with late recurrence than in those without late recurrence following ERAT. Conclusions: The late recurrence rate is higher in the patients with ERAT compared with those without ERAT following AF ablation, and is more often noted in the patients who underwent CTI ablation and had a prolonged procedure time. Furthermore, inducibility of AF or AT immediately after ablation independently predicts late recurrence in patients with ERAT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1331‐1337, December 2010)     

导管射频消融治疗房性心动过速的体会

总结５例房性心动过速的电生理特点，探讨提高导管射频消融成功率的标测与消融方法。男１例、女４例，平时心电图正常，心动过速发作时心室率１５０～２２０ｂｐｍ，ＲＰ＞ＰＲ。大头电极在右房内标测到最早的心房激动点，在心动过速时放电。２例在冠状窦口附近、２例在右房侧壁（双大头法标测）消融成功，靶点局部电位较体表心电图的Ｐ波提前２９ｍｓ以上；１例窦房折返性心动过速，消融失败。结果表明：激动标测是最基本的方法，结合拖带或隐匿性拖带、起搏标测、机械阻断等选择靶点的方法可以提高成功率；适当选择双大头法标测能够缩短手术时间。     

心房颤动导管消融术后快速性房性心律失常的机制和治疗

随着心房颤动导管消融治疗的日益广泛开展,导管消融术后快速性房性心律失常（即继发性房性心律失常,包括房性心动过速和心房扑动）逐渐成为临床心律失常治疗的关注热点,其机制在不同患者中不尽相同,甚至同一患者亦可涉及多种机制,因此这种心律失常的处理可能较心房颤动本身更为棘手。现就心房颤动导管消融术后发生快速性房性心律失常的可能机制及其防治策略作一综述。     

Outcome of Ablation for Sustained Focal Atrial Tachycardia in Patients With and Without a History of Atrial Fibrillation

Objectives: The aim of this study was to determine the long-term results of ablation for sustained focal atrial tachycardia in patients with and without a history of atrial fibrillation.Methods: A history of atrial fibrillation was documented in 25 of 111 patients (23%) with focal atrial tachycardias. We studied the results of focal ablation during a follow-up of 27 ± 22 months.Results: Enlargement of left atrium (Odds ratio 2.99) and septal origin of the atrial focus (Odds ratio 5.68) were independent predictors of coexisting atrial fibrillation. Patients with a septal origin of the focal atrial tachycardia were older (62 vs. 54 years) and had a higher rate of structural heart disease than patients with a non-septal site of origin (51 vs. 29%). A higher rate of atrial fibrillation was found in patients with anteroseptal (56%), midseptal (50%) and posteroseptal (36%) atrial tachycardias than in patients with focal atrial tachycardias arising from the crista terminalis (9%), the tricuspid (12%) and mitral annulus (0%), the ostia of thoracic veins (17%) and other right atrial (27%) and left atrial free wall sites (10%). During the follow-up, atrial fibrillation was documented in 3% of patients without preexisting atrial fibrillation. In patients with focal atrial tachycardia and a history of atrial fibrillation, at least one episode of atrial fibrillation was documented during follow-up in 64% of patients, but 60% of patients reported marked symptomatic improvement.Conclusion: An increased rate of coexisting atrial fibrillation was found in patients with a septal origin of focal atrial tachycardia. Ablation of the focal atrial tachycardia may eliminate both arrhythmias, but patients with a history of atrial fibrillation may still be prone to recurrences of atrial fibrillation after focal ablation.     

Electrophysiological Characteristics of Localized Reentrant Atrial Tachycardia Occurring After Catheter Ablation of Long-Lasting Persistent Atrial Fibrillation

Background: Mapping of recurrent atrial tachycardia (AT) after extensive ablation for long-lasting persistent atrial fibrillation (AF) is complex. We sought to describe the electrophysiological characteristics of localized reentry occurring after ablation of long-lasting persistent AF.
Methods: Out of 70 patients undergoing catheter ablation of long-lasting persistent AF, 9 patients (13%, 55 ± 8 years, 8 males) in whom localized reentry was demonstrated in a repeat ablation were studied. Localized reentry was defined as reentry in which the circuit was localized to a small area and did not have a central obstacle. The mechanism of AT was determined by electroanatomical and entrainment mapping.
Results: Nine localized reentries with cycle length of 243 ± 41 ms were mapped in 9 patients. The location of AT was the left atrial appendage in 4 patients, anterior left atrium in 2, left septum in 2, and mitral isthmus in 1. In all ATs, a critical isthmus of <10 mm in width was identified in the vicinity of the prior linear lesions or ostia of isolated pulmonary veins. Ablation of the critical isthmus, which was characterized by continuous low-voltage activity (median voltage: 0.15 mV, mean duration: 117 ± 31 ms), terminated AT and rendered it noninducible. Additionally, ablation was performed for all of inducible ATs. At 11 ± 7 months after the procedure, 8 of 9 patients (89%) were free from any arrhythmias.
Conclusions: After ablation of long-lasting persistent AF, localized reentry may arise from a site in the vicinity of the prior ablation lesions. Ablation of the critical isthmus eliminates the arrhythmia.     

Lobectomy for Pulmonary Vein Occlusion Secondary to Radiofrequency Ablation

Pulmonary Vein Occlusion After RF Ablation . Pulmonary vein stenosis, a recognized complication of transcatheter radiofrequency ablation in the left atrium, is often asymptomatic. Significant stenosis is commonly treated with percutaneous balloon dilation with or without stenting. We encountered a case of complete pulmonary vein occlusion that caused lobar thrombosis, pleuritic pain, and persistent cough. Imaging studies revealed virtually no perfusion to the affected lobe. A lobectomy was performed, resolving the persistent cough and pain. Pulmonary vein occlusion should be suspected in patients who present with pulmonary symptoms after having undergone ablative procedures for atrial fibrillation. This condition may necessitate surgical intervention if interventions such as balloon dilation or stenting are not possible or are ineffective. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1055‐1058, September 2010)     

Tachycardia-Induced Right Ventricular Cardiomyopathy: Epicardial Radiofrequency Ablation of an Unusual and Unexpected Ventricular Tachycardia

A 38-year-old man without prior medical history was hospitalized for sustained monomorphic ventricular tachycardia (VT) left bundle branch block pattern with inferior QRS axis resistant to beta blockers. Right ventricular (RV) ejection fraction (EF) was 28%. Left ventricular EF was normal. Right and left endocardial ablation failed. Percutaneous epicardial radiofrequency application at the lateral mitral annulus was successful. The RVEF later normalized.
Some VTs originating from the left ventricular epicardium are potential mimickers of benign VTs originating from the ventricular outflow tract (right or left) or arrhythmogenic right ventricular cardiomyopathy VT and they may induce isolated RV dysfunction.