Acceleration of Atrial Ectopic Tachycardia as a Guide to Successful Radiofrequency Ablation

Three chiidren with atrial ectopic tachycardia (AET), ages 7–10 years, underwent radiofrequency ablation (RFA). Two had AET localized to the inferolateral orifice of the right atrial appendage, one had AET at the posteroinferior orifice of the left atrial appendage. Each patient received RFA at 15–16 watts for 30 seconds per application. Acceleration of AET rate was observed only during successful RFA application in each palienf. occurring within 5 seconds and Jasfing 2–4 seconds. All unsuccessful applications failed to show this phenomenon. Observation of acceleration of AET rate during RFA was a useful predictor of successful procedure, possibly indicating destruction of abnormally automatic substrates.     

三维电解剖标测系统指导下射频消融房性心动过速的临床研究

目的：探讨三维电解剖标测系统（CARTO）指导下进行房性心动过速射频消融的方法及效果。方法：对40例房性心动过速患者应用CARTO标测心房,构建三维电解剖图,分析房性心动过速的电生理机制。局灶性房速消融最早激动点,大折返性房速消融折返环的关键性峡部。选择利用常规方法行消融的28例患者作为对照组。比较两组消融的成功率、X线曝光时间。结果：38例患者CARTO三维标测系统标测提示为局灶性房性心动过速,最早激动点位于右心房35例,其中冠状静脉窦口8例（20%）、间隔部10例（25%）、侧壁8例（20%）、上腔静脉口附近4例（10%）、后壁4例（10%）,1例患者（2.5%）有3种类型房速（分别为间隔部、上腔静脉口的局灶房速和三尖瓣峡部依赖的大折返房速）。位于左心房的局灶房速3例,分别位于右上肺静脉口（2.5%）、左上肺静脉口（2.5%）及左心耳（2.5%）。2例患者为大折返房速（5%）,1例为三尖瓣峡部依赖性,1例为围绕界嵴的大折返房速。均消融成功（100%）,随访4～16个月,均无复发。常规消融组成功率为89.3%（P〈0.05）。CARTO组X线曝光时间比常规组明显缩短,分别为（13.8±5.5）min和（30.4±12.9）min,差异有统计学意义（P〈0.05）。结论：应用CARTO标测房性心动过速,对分析房性心动过速的机制准确快速,能有效指导射频消融。     

Successful Radiofrequency Catheter Ablation of Automatic Atrial Tachycardia with Regression of the Cardiomyopathy Picture

Ectopic atrial tachycardia (EAT) is often refractory to pharmacological suppression, and if uncontrolled, it can lead to cardiomyopathy. Although RF current catheter ablation therapy has been effective in eliminating the arrhythmia, there is limited information. particularly in adult patients with regard to the reversal of the tachycardia induced cardiomyopathy. Four adult patients, 20–56 years of age, and a 6-year-old boy, were referred with refractory EAT. Four patients had heart failure and three had depressed LV function by echocardiographic criteria. AH patients underwent electrophysiological study, and RF ablation was successful in abolishing the arrhythmogenic foci. Of these, four were located in the right atrium and one in the left atrium, and were identified by recording of the earliest atrial activation. No complications occurred. Termination of the EAT resulted in symptomatic improvement. Serial echocardiographic assessment of LV function indicated a significant reversal of the cardiomyopathy picture with reduction in chamber size and recovery in systolic function; indices of diastolic dysfunction persisted in one patient. Chronic, uncontrolled EAT can cause tachycardia induced cardiomyopathy. The picture of the cardiomyopathy resolves after elimination of the focus. RF ablation is both effective and safe, and may be considered as early therapy, particularly in patients with incessant EAT and ventricular dysfunction.     

Atrial Tachycardia as a Proarrhythmic Effect of Radiofrequency Catheter Ablation for Atrioventricular Nodal Reentrant Tachycardia

Radiofrequency catheter ablation is now the first line treatment for atrioventricular nodal reentrant tachycardia. The success rate is high with a low incidence of complications. However, a possible proarrhythmic effect of radiofrequency energy has been rarely reported and no study has demonstrated a direct correlation between the anatomic site of the radiofrequency application and the origin of a new post‐ablation arrhythmia. We present a case of a focal atrial tachycardia that occurred after slow pathway radiofrequency catheter ablation for atrial nodal reentrant tachycardia and originating close to the previous ablation site. This tachycardia was successfully treated with a second ablation session. (PACE 2011; 34:e33–e37)     

Radiofrequency Catheter Ablation of Atrial Tachycardia with Unusual Left Atrial Sites of Origin: Report of Two Cases

Two cases of successful radiofrequency catheter ablation of adult-onset atrial tachycardia originating from the left atrium adjacent to the mitral annulus are presented. Endocardial catheter activation mapping performed by retrograde or atrial transseptal approach revealed presystolic activation at the successful ablation site in both patients, and fractionation during sinus rhythm and tachycardia in one. The 12 lead electrocardiogrnphic P wave appearance was suggestive of a left atrial tachycardia origin in both cases.     

Effect of Mitral Isthmus Block on Development of Atrial Tachycardia Following Ablation for Atrial Fibrillation

Background: Successful mitral isthmus (MI) ablation may reduce recurrence of atrial fibrillation (AF) and macro‐reentrant atrial tachycardia (AT) after pulmonary vein isolation (PVI) for AF. Objective: To determine if achieving bidirectional MI conduction block (MIB) during circumferential pulmonary vein ablation (CPVA) plus left atrial linear ablation (LALA) affects development of AT. Methods: Sixty consecutive patients with persistent (n = 25) or paroxysmal (n = 35) AF undergoing CPVA plus LALA at the MI and LA roof were evaluated in a prospective, nonrandomized study. Results: PVI was achieved in all patients. Bidirectional MI block was achieved in 50 of 60 patients (83%). During 18 ± 5 months follow‐up, 12 patients (20%) developed recurrent AF and 15 (25%) developed AT. Patients in whom MIB was not achieved at initial ablation had four times higher risk of developing AT (P = 0.008, 95% confidence interval 1.43–11.48) versus patients with MIB. In 12 patients with AT undergoing repeat ablation, 22 ATs were identified, with reentry involving the MI in nine, the LA roof in six, and the ridge between the LA appendage and left PVs in seven. In patients with MIB at initial ablation, recovery of MI conduction was seen in eight of 13 undergoing repeat ablation. Conclusions: AT occurring after CPVA plus LALA is often due to incomplete MI ablation, but may also occur at the LA roof, and ridge between the LA appendage and left PVs. Failure to achieve MI block increases the risk of developing AT. Resumption of MI conduction may also be a mechanism for AT recurrence. (PACE 2010; 460–468)     

Slow Potential-Guided Radiofrequency Catheter Ablation in Atrioventricular Nodal Reentrant Tachycardia: Characteristics of the Potential Associated with Successful Ablation

To examine the characteristics of Haïssaguerre's slow potential (SP) specific to effective catheter ablation of the slow pathway in AV nodal reentrant tachycardia, the properties of SP and its recording site ware analyzed in 52 patients who underwent successful SP-guided ablation. The properties of SP included the ratio of the amplitude of SP to that of atrial potential (A)(SP/A), the SP duration, the interval between His-bundle potential (HP) and SP (HP-SP), the interval between A and SP (A-SP), the interval between SP and ventricular potential (V) (SP-V), and the ratio of A-SP to the interval between A and the V (A-SP/A-V). The SP recording site was determined by the ratio of the amplitude of A to that of V (A/V) and by the relative position of the ablation catheter on X ray (right anterior oblique projection), expressed as the ratio of the distance between the coronary sinus ostium and SP site to that between the coronary sinus ostium and HP recording site (relative SP position). Twenty-eight slow pathways were ablated with a single energy application, while the other 24 required applications ≥ 2. In all successful applications, SP/A, SP duration, HP-SP, A-SP. SP-V, A-SP/A-V, A/V, and relative SP position were 51 %± 25%, 28 ± 5 ms, -11 ± 9 ms, 57 ± 25 ms, 68 ± 13 ms, 46%± 9%, 15%± 13%, and 51%± 13%, respectively. A significant correlation was observed between the relative SP position and A-SP, and between the relative SP position and A-SP/A-V (r = 0.60 and 0.37, respectively), while it was not between the relative SP position and HP-SP, nor between the relative SP position and SP-V. When the characteristics of SP were comparatively analyzed between the effective and ineffective applications in 24 patients in whom applications ≥ 2 were required, there was no difference observed in HP-SP, A-SP, SP-V, A-SP/A-V, and A/V. However, SP/A, SP duration, and the relative SP position in the effective applications were all greater than those in the ineffective ones (56%± 20% vs 35%± 18%, P < 0.001; 29 ± 4 vs 26 ± 5 ms, P < 0.01; and 52%± 15% vs 33%± 11%, P < 0.001, respectively). These results indicate that SP with an amplitude over a half of A amplitude and recorded at the mid-septum of the tricuspid annulus can be a marker for successful slow pathway ablation. Although the local atrial electrogram appears late as the SP recording site shifts to the lower position, the timing of SP relative to HP and V remained unchanged, suggesting that SP is independent of the local atrial activation.     

One-to-Two Atrioventricular Conduction Causing Nonreentrant Tachycardia: Successful Treatment with Radiofrequency Ablation

The anatomical substrate for AV nodal reentrant tachycardia (AVNRT) is well known and is due to anterograde conduction through a siow conducting pathway and retrograde conduction using a fast conducting path way. In this report, we describe a patient with AVNRT who also presented with frequent episodes of paroxysmal nonreentrant tachycardia due to the occurrence of two conducted ventricular beats for each sinus depolarization. Palpitations and arrhythmias were abolished after radiofrequency ablation of the slow pathway.     

Symptomatic Sinus Tachycardia with Perpetuating Slow Pathway: Successful Treatment with Radiofrequency Ablation

We report a case of sinus tachycardia with perpetuating slow pathway (SP) conduction in a 42‐year‐old woman who developed severe symptoms as a result of atrioventricular (AV) desynchronization. The restoration of an AV synchrony, achieved with selective radiofrequency ablation of the SP, eliminated the symptomatic arrhythmia and may represent a reasonable therapeutic option despite the fact that the patient has no AV‐node reentrant tachycardia. This case demonstrates the importance of AV timing.     

A Case with Catecholaminergic Polymorphic Ventricular Tachycardia Unmasked after Successful Ablation of Atrial Tachycardias from Pulmonary Veins

Catecholaminergic polymorphic ventricular tachycardia (VT) is characterized by polymorphic VT during exercise, and the association of atrial fibrillation (AF) has been reported. However, the mechanism of AF in this disease and the relationship between VT and AF has been obscured. We described a 13-year-old girl who referred for catheter ablation of exercise-induced paroxysmal AF. Multifocal atrial tachycardia mimicking AF on the surface electrocardiogram originated from multiple pulmonary veins (PVs). While AT became non-inducible after the isolation of four PVs, polymorphic VT was initiated by isoproterenol infusion. Polymorphic VT was suppressed during rapid atrial pacing.     

Clinical, Electrophysiological Characteristics, and Radiofrequency Catheter Ablation of Atrial Tachycardia Near the Apex of Koch's Triangle

Atrial tachycardia, with its focus near the apex of Koch's triangle, may carry a potential risk of atrioventricular block during radiofrequency catheter ablation. The efficacy and safety of this procedure have never been addressed. The characteristics and catheter ablation results are reported for six patients with atrial tachycardia near the apex of Koch's triangle. All six patients were female aged 49.6 ± 9.3 years (range 39–63). Organic heart disease was present in 3 (50%) of the 6 patients. The P wave in surface ECG had a mean axis of − 28° (range − 90°–+ 30°) in the frontal plane. The catheter ablation was guided by activation sequence mapping. The energy was titrated from low power level. Atrial overdrive pacing was used to monitor the atrioventricular conduction should accelerated functional rhythm occur. At the final successful ablation site, the local atrial activation was 41.8 ± 9.1 ms before the P wave and His-bundle potential was present in 5 of the 6 patients. All patients had their atrial tachycardia eliminated without recurrence or heart block during a follow-up period of 17.7 ± 8.5 months (range 6–30). In conclusion, atrial tachycardia near the apex of Koch's triangle has distinct clinical and electrophysiological features, Radiofrequency catheter ablation can be performed effectively. However, extreme care must be taken to prevent inadvertent atrioventricular block. Titrated energy application and continuous monitoring of atrioventricular conduction are mandatory.     

Long-Term Clinical Outcome of Right Bundle Branch Radiofrequency Catheter Ablation for Treatment of Bundle Branch Reentrant Ventricular Tachycardia

This study assessed the long-term outcome of patients undergoing radiofrequency ablation of the right bundle for bundle branch reentrant ventricular tachycardia. Bundle branch reentrant tachycardia was diagnosed in 16 patients (ejection fraction 31%± 15%) who underwent electrophysiology study in our laboratory. All patients had His-Purkinje system conduction delay with mean HV interval of 68 ± 8 ms. After ablation, right bundle branch block developed in 15 patients. One patient developed complete heart block, which was anticipated. One patient died of heart failure 9 months after ablation. Two patients were successfully bridged to heart transplantation 0.5 and 13 months, respectively, after ablation. Two patients received implantable defibrillators for other ventricular tachycardias. One patient had syncope 11 months after ablation, but there was no evidence of ventricular tachycardia or heart block in repeat electrophysiology study. This patient died suddenly 29 months after ablation. The remaining nine patients were alive and well for a mean follow-up of 19 ± 10 months. Radiofrequency ablation of the right bundle branch is an effective therapy for treatment of bundle branch reentrant ventricular tachycardia. Survival is excellent provided that other types of ventricular tachycardia, when present, are treated as well. This technique maybe helpful in management of patients who have unacceptable frequent shocks from their implanted defibrillators and may be helpful in avoiding implantation of such a device completely in others. In some patients with terminal heart failure and incessant ventricular tachycardia, this procedure can function as a bridge to cardiac transplantation.     

Ablation of a Resistant Right Atrial Appendage Tachycardia Using a Magnetic Navigation System

The right atrial appendage is an uncommon site of origin for ectopic atrial tachycardia. Right atrial appendage tachycardia (RAAT) has been noted to be prevalent in young males and responds well to radiofrequency ablation. We report a case of RAAT resistant to multiple attempts of ablation that responded to ablation using Stereotaxis Niobe? Magnetic Navigation System (RMN, Stereotaxis, St. Louis, MO, USA). (PACE 2013; 36:e15–e18)     

Radiofrequency Catheter Ablation of Left Atrial Tachycardia Originating Within the Pulmonary Vein in a Patient with Dextrocardia

A case is presented of a 38-year-old male with dextrocardia in whom radiofrequency current ablation of an incessant atrial tachycardia originating within the infero-lateral pulmonary vein was achieved. Activation mapping with detection of the earliest atrial activation was used for identification of the arrhythmogenic focus. In addition to fluoroscopy, trans- esophageal echocardiography was used for catheter guidance during the transseptal puncture. The present experience suggests that location of an arrhythmogenic focus within the pulmonary venous system should be considered whenever early atrial activation during ectopic atrial tachycardia is recorded at the junction between thfi left atrium and the pulmonary veins.     

Successful Catheter Ablation of Human Ventricular Tachycardia with Radiofrequency Current Guided by an Endocardial Map of the Area of Slow Conduction

A case is presented of a 68-year-old male patient with a history of myocardial infarction and recurrent ventricular tachycardia who was successfully treated with a single 20-second transcatheter application of radiofrequency current. Prior to current application a complete endocardial map had been obtained of an area of slow conduction that extended caudo-cranially for approximately 2 cm along the lower left ventricular septum. Stimulation techniques yielded evidence that this area was critically related to tachycardia initiation and maintenance. Its central part was subsequently chosen as the site for current delivery.     

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.     

Ablation of atrioventricular nodal reentrant tachycardia in a patient with tricuspid atresia guided by electroanatomic mapping

We describe a case of ablation of atrioventricular nodal reentrant tachycardia in a patient with tricuspid atresia and L-malposition of great vessels using an electroanatomical mapping system integrated with cardiac magnetic resonance imaging. Atrial activation mapping during tachycardia identified the retrograde fast pathway proximal to the His bundle, observed in the left interatrial septum. Ablation was successfully completed below this area. Map integration with the patient's anatomy allowed a safe, individualized procedure.     

Successful Radiofrequency Catheter Ablation for Macroreentrant Ventricular Tachycardias in a Patient with Tetralogy of Fallot After Corrective Surgery

CHINUSHI, M., et al .: Successful Radiofrequency Catheter Ablation for Macroreentrant Ventricular Tachycardias in a Patient with Tetralogy of Fallot After Corrective Surgery . Radiofrequency (RF) catheter ablation was applied to two macroreentrant ventricular tachycardias (VTs) documented after corrective operation for tetralogy of Fallot. The activation wavefront of VT with a right bundle branch block pattern was found to revolve in a clockwise manner around a presumed myotomy scar in the right ventricle, and VT with a left bundle branch block pattern revolved around the same anatomical obstacle in a counterclockwise manner. In both VTs, the biggest conduction delay was confirmed at the right ventricular outflow tract. RF applications to the slow conduction area terminated each VT within a few seconds but were insufficient to cure the VTs. RF lesions were then applied to the, slow conduction area in a line to intersect the macroreentrant circuit, and both VTs became noninducible.