Gated blood-pool SPECT evaluation of changes after radiofrequency catheter ablation of accessory pathways: evidence for persistent ventricular preexcitation despite successful therapy

OBJECTIVES: This study was designed to prospectively evaluate the effects of radiofrequency ablation in Wolff-Parkinson-White (WPW) syndrome by scintigraphic analysis. BACKGROUND: The functional changes triggered by radiofrequency current ablation of atrioventricular accessory pathways are not fully known. METHODS: Forty-four patients with WPW syndrome were consecutively investigated before and 48 h after radiofrequency therapy. Fourteen patients had right sided atrioventricular pathways and 30 patients had left sided bypass-tracts. Planar gated imaging and gated blood pool tomography were performed in all of these patients. RESULTS: A significant increase in the left ventricular ejection fraction (LVEF) was demonstrated in patients with left preexcitation (62.2+/-7.9% before ablation against 64.4+/-6.3% after ablation, p = 0.02) but not for those with right sided anomalous pathway. Phase analysis only gave significant differences following ablation of right sided pathways (left-to-right phase difference = 14.4+/-13.8 degrees before ablation versus 7.5+/-7.2 degrees after ablation, p<0.05). Early abnormal ventricular contraction persisted in 12 patients with right accessory pathways and in 8 patients with left accessory pathways despite the complete disappearance of any abnormal conduction as proven electrophysiologically. CONCLUSIONS: Following catheter ablation of atrioventricular accessory pathways: 1) an improvement of left ventricular function may be seen, particularly in patients with left sided accessory pathways, and 2) unexpected persistence of local ventricular preexcitation at the site of successful ablation may be detected.     

射频导管消融房室结改良术心电监测分析

为探讨射频导管消心室改良术所致心律失常的发生规律，分析射频导管消融房室结改良术２２例术中及术后２４ｈ的心电监测资料，并与预激旁道消融术２２例进行对比研究。     

Risk of sudden death after successful accessory atrioventricular pathway ablation in resuscitated patients with Wolff-Parkinson-White syndrome

INTRODUCTION: Cardiac arrest in patients with Wolff-Parkinson-White (WPW) syndrome can be due to ventricular fibrillation mediated by fast conduction over the accessory pathway during atrial fibrillation. However, if primary ventricular fibrillation is the reason for resuscitation, placement of an implantable cardioverter defibrillator (ICD) would be indicated. The aim of this study was to test the hypothesis that in resuscitated patients with WPW syndrome, recurrences can be prevented by sole ablation of their accessory pathways. METHODS AND RESULTS: We performed a long-term follow-up study of 48 resuscitated patients with WPW syndrome who underwent successful accessory pathway ablation as their sole primary treatment. Cardiac arrest had occurred either spontaneously in 32 patients (group A) or after intravenous administration of antiarrhythmic drugs in 16 patients (group B) and was never associated with an acute myocardial infarction or other concomitant factors. All patients had normal left ventricular function at echocardiography. A total of 56 accessory AV pathways were ablated successfully with radiofrequency current (n = 55) or during surgery (n = 1) and were located at the left free wall (n = 35), right free wall (n = 8), or septal-paraseptal region (n = 13). Follow-up 5.0+/-1.9 years after ablation (range 0.2 to 7.9) was obtained in all 48 patients. All of the patients were alive, and none had a life-threatening arrhythmia or syncope after successful ablation of their accessory pathways. CONCLUSION: In resuscitated patients with WPW syndrome who have normal left ventricular function at echocardiography and no ECG abnormalities suggesting additional electrical disease, ablation of their overt accessory pathways prevented cardiac arrest recurrences; therefore, ICD placement is generally not indicated.     

Clinical application of radiofrequency ablation]

I. Radiofrequency ablation of atrioventricular accessory pathway in patients with WPW syndrome: Seventeen accessory pathways in 15 patients with Wolff-Parkinson-White syndrome (WPW) were ablated with radiofrequency current. There were 15 accessory pathways located on the left side of the heart (12 left free wall, 1 posterioseptal, 1 posteriolateral and 1 midseptal) and 2 pathways on the right side (1 right free wall, 1 anterioseptal). 16 accessory pathways (94.1%) in 14 patients were permanently abolished. Plasma CK-Mb, SGOT and LDH increased moderately in 7 cases (46.7%) and decreased to normal level in 3-4 days. Conclusion: catheter ablation of accessory pathways with radiofrequency current is a safe and effective therapeutic method for patients with refractory tachycardias mediated by these pathways. II. Radiofrequency ablation of slow pathways to cure AV nodal reentrant tachycardia: Radiofrequency energy was used to selectively ablate the slow pathways in 8 patients with atrioventricular nodal reentrant tachycardia. The slow pathways in all 8 cases were ablated successfully and no episodes of tachycardia could be induced. The A-H, H-V interval and P-R interval of ECG did not change significantly. The Wenckebach points of atrioventricular node remained unchanged. The effective refractory periods of the fast pathways were shortened in 3 and prolonged in 5 cases after the procedure. There were no severe complications. No tachycardia recurred during the follow-up period between 2 weeks and 7 months.     

Effect of radiofrequency ablation of accessory atrio-ventricular junctions on electromechanical coupling of the myocardium in children with manifesting Wolf-Parkinson-White syndrome

Aim of the study was to assess immediate and remote hemodynamic and electromechanical effects of radiofrequency ablation of accessory atrio-ventricular pathways in children with manifesting Wolf-Parkinson-White (WPW) syndrome. Radiofrequency ablation of accessory atrio-ventricular pathways resulted in diminishment of intraventricular dyssynchrony, what appeared as lowering of the degree of heterogeneity of electromechanical intervals and was associated with significant augmentation of left ventricular stroke volume. Presence of pronounced intraventricular asynchrony might be an additional indication to radiofrequency ablation of accessory atrio-ventricular pathways in patients with WPW syndrome without history of documented attacks of tachycardia.     

Ventricular excitation maps using tissue Doppler acceleration imaging: potential clinical application

OBJECTIVES: The purpose of this study is to validate the use of tissue Doppler acceleration imaging (TDAI) for evaluation of the onset of ventricular contraction in humans. BACKGROUND: Tissue Doppler acceleration imaging can display the distribution, direction and value of ventricular acceleration responses to myocardial contraction and electrical excitation. METHODS: Twenty normal volunteers underwent TDAI testing to determine the normal onset of ventricular acceleration. Two patients with paroxysmal supraventricular tachycardia and 30 patients with permanent pacemakers underwent introduction of esophageal and right ventricular pacing electrodes, respectively, and were studied to visualize the onset of pacer-induced ventricular acceleration. Eight patients with dual atrioventricular (AV) node and 20 patients with Wolff-Parkinson-White (WPW) syndrome underwent TDAI testing to localize the abnormal onset of ventricular acceleration, and the results were compared with those of intracardiac electrophysiology (ICEP) tests. RESULTS: The normal onset and the onset of dual AV node were localized at the upper interventricular septum (IVS) under the right coronary cusp within 25 ms before the beginning of the R wave in the electrocardiogram (ECG). In all patients in the pacing group, the location and timing of the onset conformed to the positions and timing of electrodes (100%). In patients with WPW syndrome, abnormal onset was localized to portions of the ventricular wall other than the upper IVS at the delta wave or within 25 ms after the delta wave in the ECG. The agreement was 90% (18 of 20) between the abnormal onset and the position of the accessory pathways determined by ICEP testing. CONCLUSIONS: These results suggest that TDAI is a useful noninvasive method that frequently is successful in visualizing the intramural site of origin of ventricular mechanical contraction.     

Ventricular fibrillation as a primary manifestation of Wolff–Parkinson–White syndrome

Wolff–Parkinson–White syndrome (WPW) is defined as a condition involving an accessory pathway associated with symptoms. A typical ECG pattern of a pre-excitation shows a short PQ interval, presence of delta wave and a broad QRS complex on surface ECG. The underlying mechanism involves an accessory pathway, which enables conduction of a depolarization wave from atria to ventricles bypassing the AV node and predisposes to arrhythmias and sudden cardiac death. The most common arrhythmia in patients with WPW syndrome is atrioventricular reentrant tachycardia. However, it is not present in all patients with pre-excitation [1], [2], [3], [4]. Up to 1/3 of patients with AVRT experience atrial fibrillation, which may be conducted to ventricular myocardium via the accessory pathway and lead to a life-threatening ventricular fibrillation. The most effective treatment of the WPW syndrome is a radiofrequency catheter ablation [2], [5], [6], [7], [8]. This paper describes a case of a 40-year-old woman after a cardiopulmonary resuscitation for ventricular fibrillation, which was a primary manifestation of the WPW syndrome. It focuses on pathophysiology, clinical pattern and treatment possibilities of patients with WPW syndrome.     

Doppler predictors of inducibility of atrial fibrillation in patients with WPW syndrome and atrioventricular re-entrant tachycardia

BACKGROUND: Atrial fibrillation (AF) in patients with Wolff-Parkinson-White syndrome (WPW) may induce complex ventricular arrhythmias resulting in sudden cardiac death. It is essential to find an effective non-invasive diagnostic method allowing to select patients at risk of life-threatening arrhythmias. Our objective was to examine Doppler predictors of AF in patients with WPW and atrioventricular re-entrant tachycardia (AVRT). MATERIAL AND METHODS: 65 patients with WPW and AVRT (33 men, mean age 39 +/- 11 y) were prospectively studied. In all patients TTE was performed with measurements of left ventricle (LV) diameters, volumes and parameters of systolic and diastolic function. TTE was followed by invasive electrophysiology study (EPS) and radiofrequency current ablation of accessory pathway.AF lasting at least 30 s was induced in 29 (44.6%) patients during EPS. Reduction of right upper pulmonary vein (RUPV) systolic velocity (P < 0.005) and systolic to diastolic velocity ratio (P < 0.005) and increase in atrial reversal velocity (P < 0.05) of RUPV flow and difference between duration of RUPV atrial reversal flow and A wave of mitral profile (P < 0.05) were associated with increased risk of AF in patients with WPW syndrome and AVRT. Systolic and atrial reversal velocities were identified as independent predictors of AF in those patients. CONCLUSIONS: Systolic and atrial reversal right upper pulmonary vein flow velocities have been shown to be independent predictors of AF inducibility in patients with Wolff-Parkinson-White syndrome and atrioventricular re-entrant tachycardia.     

The catheter ablation of accessory atrioventricular pathways using a radiofrequency]

Sixteen consecutive patients (5 males and 11 females) aged 40 +/- 22 years suffering for spontaneous symptomatic arrhythmias underwent attempted transcatheter ablation of an atrioventricular accessory pathway using radiofrequency current. Five patients had the WPW syndrome. The Kent bundle was located in the left free wall in 14 patients, in the right anteroseptal region in one patient and in the posteroseptal zone in one patient. A 7F catheter (Polaris, Mansfield) with a 4 mm2 distal electrode, was used for ablation positioned on the left atrioventricular annulus in the 13 patients with left free wall accessory pathways or at the right atrium in the two patients with right accessory pathways. Without general anesthesia, a mean of 12 +/- 9 applications of radiofrequency current were delivered between the large tip electrode and a large skin patch positioned on the left posterior chest. By using radiofrequency current, a successful clinical outcome was achieved in 14 of 16 patients (87%). In patients with concealed accessory pathways, accessory conduction was abolished in 10 of 11 patients, in 8 patients in the first radiofrequency session and in two other patients in a successful second procedure. In the 5 patients with the WPW syndrome, the anterograde conduction disappeared after the procedure but the retrograde conduction remained, although deteriorated, in 2 patients. One patient developed uncomplicated tibioperoneal thrombophlebitis and in 2 cases an elevated concentration of creatine kinase value was found. In one female patient with a concealed accessory pathway, the Kent bundle conduction reappeared 3 months after the procedure and was ablated in a second session.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical and electrophysiological study of asymptomatic Wolff-Parkinson-White syndrome

AIM: This study was designed to describe clinical characteristics and electrophysiologic in patients with asymptomatic Wolff-Parkinson-White syndrome. METHODS: From December 2000 to August 2005, a total of 154 patients with accessory pathway-mediated reentry mechanism underwent electrophysiologic studies at Sainte-Marguerite and Timone hospitals in Marseille. Ninety-six patients had WPW syndrome, out of which 78 were symptomatic patients and 18 were asymptomatic. The mean age was 26 years. Sex (masculine) 17. RESULTS: The incidence of intermittent arrhythmia associated with Wolff-Parkinson-White syndrome was lower in 2 patients (11%). There was a higher occurrence of rapid induced tachycardia in 9 patients (50%). However, atrial fibrillation occurred more commonly in 6 (33%) patients. The anterograde accessory pathway effective refractory period (APRP) in patients was much shorter (less than 250 ms [N=16]) 13 patients with accessory pathways were managed by ablation. CONCLUSION: This study demonstrated the difference in the electrophysiologic characteristics of anterograde accessory pathway and the atrioventricular node in asymptomatic WPW patients, and thus concluded that radiofrequency (RF) catheter ablation is a safe and effective method to manage patients with asymptomatic WPW syndrome.     

经导管射频消融治疗预激综合征方法学初探

作者采用40MHz的射频对6例预激综合征并阵发性室上性心动过速的患者分别行冠状窦消融和房室结改良术,2例有效。初步认为冠状窦消融有一定局限性。此与射频消融作用局限需精确定位以及旁道远离冠状窦内标测电极有关。用房室结改良术或用吸附电极导管有望提高治疗预激综合征的疗效。     

Usefulness of predischarge electrophysiologic study in predicting late outcome after surgical ablation of the accessory pathway in the Wolff-Parkinson-White syndrome.

A predischarge electrophysiologic study was performed in 113 patients with the Wolff-Parkinson-White (WPW) syndrome who had undergone surgical ablation of the accessory pathway. The study was performed 5 to 20 (mean 10 +/- 3) days after surgery. There were 82 male and 31 female patients (aged 4 to 58 years, mean 36 +/- 13). Sixty-one patients (54%) had manifest, 52 (46%) had concealed and 12 (11%) had multiple accessory pathways. All but 1 patient had atrioventricular reentrant tachycardia incorporating single or multiple accessory pathways during the control electrophysiologic study. The accessory pathways were located in the left ventricular free wall in 60% of cases, right ventricular free wall in 22%, posteroseptum in 13%, and anteroseptum in 5%. The predischarge electrophysiologic study showed that the accessory pathway was capable of anterograde and retrograde conductions in 4 patients (all with manifest WPW syndrome). Four patients showed induction of supraventricular tachycardia, including 2 with atrioventricular reentrant tachycardia, and 2 with atrioventricular nodal reentrant tachycardia. Recurrence of supraventricular tachycardia was noted in 5 patients during a follow-up of 28 +/- 26 months. Of these 5 patients, 2 had inducible and 3 had no inducible supraventricular tachycardia during the predischarge electrophysiologic study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Determination of the site of the accessory pathway in WPW syndrome by an electrocardiographic inverse solution

The initial portion of the QRS complex in WPW syndrome might be represented by a single dipole, since the delta wave corresponds to the localized ventricular activation propagated over the accessory atrioventricular pathway. In order to examine whether the site of the accessory pathway in WPW syndrome could be localized by an equivalent dipole method, the dipole positions during the delta wave were determined in 30 patients using a three dimensional model of the torso and were then compared with the sites of accessory pathways localized by body surface maps. The single dipole approximation during the delta wave appeared to be appropriate since the index of the nondipolarity of the potentials was as low as 28% on average. The dipole positions determined on the atrioventricular ring during the delta wave were compatible with the sites of accessory pathways localized by body surface maps in 22 of the 30 patients. The dipole positions were adjacent to the sites of accessory pathways in 7 of the remaining 8 patients. Thus the equivalent dipole method might be an additional noninvasive tool to determine the site of the accessory pathway in WPW syndrome.     

房室旁道间歇性逆传阻滞的探讨ioven

为探讨房室旁道间歇性逆传阻滞的发生机制及临床意义 ,对房室旁道患者射频导管消融术中作腔内电生理检查 ,观察房室顺传和室房逆传功能及途径。结果显示261例中有7例 (4例为隐匿性预激综合征 )为旁道逆向 (或双向 )传导阻滞 (2.7% )。尽管旁道间歇性逆传阻滞是一种少见现象 ,但由于旁道传导阻滞 ,无法对旁道进行定位及射频导管消融 ,因此了解旁道有无间歇性逆传阻滞 ,对射频导管消融治疗有临床意义     

Catheter ablation of the accessory pathways of the Solff-Parkinson-White syndrome and its variants

The basis of arrhythmias in the Wolff-Parkinson-White (WPW) syndrome and its variants is the presence of accessory atrioventricular connections. Those variants include the concealed form of the WPW syndrome, the permanent form of junctional reciprocating tachycardia, and Mahaim preexcitation. In all forms of symptomatic WPW syndrome, catheter ablation of the accessory atrioventricular connections using radiofrequency current has become the treatment of choice. This review traces the development of this therapy, outlines the basics of the technique, summarizes the results reported in the largest series, indicates remaining areas of controversy, and discusses the indications and limitations of radiofrequency ablation therapy.     

Ebstein畸形合并右侧旁道的射频导管消融治疗

目的探讨Ebstein畸形合并右侧旁道的射频导管消融（下称消融）手术方法。方法选择我院26例Ebstein畸形合并右侧旁道的患者行心内电生理检查确定旁道最佳消融靶点,适当增加射频能量和消融时间以到达消融目的。结果26例Ebstein畸形合并右侧旁道的患者,成功消融23例患者共26条旁道。结论选择Webster-7F蓝把加硬Lab导管经右股静脉置于右心房三尖瓣环附近行精细标测。当Lab电图呈现小A大V波且A—V波群融合时,为最佳消融靶点。精标三尖瓣环附近最早心室点、增加射频能量是治疗Ebstein畸形并房室折返性心动过速安全、有效的方法。     

Radiofrequency catheter ablation of accessory atrioventricular pathways in children and young adults.

OBJECTIVE--To assess the efficacy of radiofrequency ablation for reentrant tachyarrhythmias in children and young adults. SETTING--A tertiary cardiac referral centre. PATIENTS AND INTERVENTIONS--Over a 16 month period 22 patients aged less than 20 years (median age 16.5 years) underwent 26 radiofrequency ablation procedures for atrioventricular reentry tachycardia through an accessory pathway. The results of radiofrequency ablation were compared with those in a group of 16 patients (median age 14 years) who had had surgical ablation for atrioventricular reentry tachycardia over a preceding six year period. RESULTS--Ablation of an accessory atrioventricular pathway was accomplished for 18 (76%) of 25 pathways in 16 (73%) of 22 patients. There were no procedure-related complications. Surgery was eventually curative in 15/16 patients (94%). However, three patients required a second open heart surgical procedure because tachyarrhythmia recurred. There were no surgical deaths. Failures for radiofrequency ablation were related to accessory pathway location, and were greater for right free wall and posteroseptal pathways (success rate of 50% and 57% respectively). Recurrence after surgery was also associated with pathways in these locations. CONCLUSIONS--Transcatheter radiofrequency current ablation was safe and achieved a cure with less patient morbidity and improved cost efficiency. It is an attractive alternative to long-term drug therapy or surgery in older children and adolescents. A higher success rate may be expected with increased experience.     

预激综合征合并心房颤动的射频消融及远期随防

探讨导管射频消融阻断房室旁道治疗预激综合征（ＷＰＷ）合并心房颤动（ＡＦ）病人的远期疗效，对连续５８例ＷＰＷ合并ＡＦ进行射频消融阻断旁道并随访观察，其中男３２例、女２２例，年龄４２±１７岁，ＡＦ病史２３±１１年，发作频度为１１±９次／年，ＡＦ时心室率１７８±２７ｂｐｍ，心电图上最短ＲＲ间期为２２１±３８ｍｓ。合并器质性心脏病９例、合并心功能不全４例。５８例中右侧旁道占９０％（５２／５８）、左侧旁道占１０％（６／５８）；单旁道５５例、双旁道３例（均为右侧旁道）。右房室环游离壁旁道３７条（６１％）、右前间隔９条（１５％）、右后间隔７条（１１％）、右中间隔２条（３％）、左游离壁４条（７％）、左后间隔２条（３％）。首次消融成功率９４％，两次消融成功率１００％，３个月内心电图上预激复发３例（５％），经再次消融成功。随访２．０±１．８年，５７例不再发作ＡＦ（９８％），１例ＡＦ复发者（２％）合并Ｅｂｓｔｅｉｎ畸形和心功能不全，消融后ＡＦ发作次数比消融前明显减少，洋地黄容易控制心室率。４例心功能不全者在旁道阻断６个月后心功能恢复正常３例、改善１例。结论：短不应期房室旁道是导致ＷＰＷ病人发作ＡＦ的重要因素之一，采用导管射频消融?     

Comparison of direct-current and radiofrequency ablation of free wall accessory atrioventricular pathways in the Wolff-Parkinson-White syndrome.

To evaluate and compare the safety and efficacy of catheter-mediated direct-current (DC) or radiofrequency (RF) ablation in patients with free wall accessory atrioventricular pathways, 95 patients with free wall accessory atrioventricular pathway-mediated tachyarrhythmias underwent catheter ablation. Immediately after ablation, 27 of 30 accessory pathways (90%) were ablated successfully with DC, but 2 of the 27 had early return of conduction and received a second ablation session; 3 of 8 (38%) and 57 of 62 (92%) accessory pathways were ablated successfully with RF through a small-tip (2 mm) and a large-tip (4 mm) electrode catheter, respectively. Complications in DC ablation included transient hypotension (2 patients) and pulmonary air-trapping (2 patients) and in RF ablation, cardiac tamponade (1 patient) and suspicious aortic dissection (1 patient); myocardial injury and proarrhythmic effects were more severe in DC ablation. Procedure and radiation exposure time were significantly longer in RF ablation (DC, 3.6 +/- 0.2 hours, 34 +/- 4 minutes; RF 4.2 +/- 0.5 hours, 50 +/- 10 minutes). This study confirms that RF ablation is associated with little morbidity and few complications, and RF ablation with a large-tip electrode catheter is an effective and relatively safe nonsurgical method for treatment of free wall accessory atrioventricular pathway-mediated tachyarrhythmias.     

体表标测q波对显性房室旁道定位的临床意义初探

为探讨房室旁道体表标测图ｑ波分布与旁道位置的关系，采用９１导联体表标测系统观察２６例显性预激综合征（单旁道）患者ｑ波分布图，并与射频消融成功靶点确定的旁道位置比较。发现旁道位置不同，ｑ波分布有别：左室游离壁旁道（１４例）ｑ波分布于左腋中线以后背部上方及右锁骨水平（１２例）；左后间隔旁道（３例）ｑ波局限于右胸背部（３例）。右侧游离壁旁道（７例）ｑ波分布于右胸背部及肋弓下缘（７例）；右前间隔旁道（１例）ｑ波位于右胸背上方（１例）；右后间隔旁道（１例）位于右胸背下方及左胸背第５肋以下（１例）。提示体表标测ｑ波分布有助于消融术前旁道定位。