Influence of Age on the Potential Risk of Sudden Death in Asymptomatic Wolff-Parkinson-White Syndrome

Sudden death might be the first event in patients with asymptomatic WPW. The purpose of the study was to know if the age of the patient modifies the electrophysiological characteristics of asymptomatic WPW. Transesophageal stimulation was performed on 92 asymptomatic WPW patients from the following age groups: 10-69 years (n = 14), 20-29 years (n = 33), 30-39 years (n = 15), 40-49 years (n = 17), and 50-69 years (n = 13). The procedure consisted of atrial pacing up to the second AV block, programmed atrial stimulation using one and two extrastimuli delivered on two driven rhythms in the control state, and after infusion of isoproterenol. In thefive age groups, paroxysmal junctional tachycardia occurred, respectively, in 1 (7%), 1 (3%), 2 (13%), 2 (12%) patients, and not at all in the oldest group. AF > 1 minute occurred, respectively, in 3 (21%), 9 (27%), 5 (33%), 3 (18%), and 4 (31%) patients. The dangerous form of WPW (rapid conduction in the Kent bundle > 240/min in the control state or > 300/min after isoproterenol + AF induction) occurred, respectively, in 3 (21%), 9 (27%), 4 (27%), 1 (6%), and 3 (23%) patients. In conclusion, electrophysiological data of asymptomatic WPW are not modified by age of the patient. Elderly patients remain at risk of a dangerous form of WPW; systematic evaluation of WPWis recommended in patients with an active life independent of age.     

Electrophysiologic Evaluation of Asymptomatic Patients with the Wolff-Parkinson-White Pattern

In the past 4 years, 34 asymptomatic patients with the Wolff-Parkinson-White (WPW) pattern underwent electrophysiologic study. The effective refractory period (ERP) of antegrade conduction over the accessory pathway was 288 +/- 29 msec. In three asymptomatic patients (9%), the antegrade ERP of the accessory pathway was shorter than 250 msec. The antegrade ERP of the accessory pathway became shorter than 250 msec in an additional 12 of 22 (55%) patients after isoproterenol administration. Nineteen (56%) of the asymptomatic patients showed the absence of retrograde conduction over the accessory pathway even after isoproterenol administration. The rate of induction of orthodromic reciprocating tachycardia in the asymptomatic WPW patients was 15% (5/34), which was significantly lower than that in the symptomatic patients. These data suggest that in the asymptomatic patients, the absence of retrograde conduction over the accessory pathway is the reason they remained asymptomatic, free of reciprocating tachycardia. However, even in the asymptomatic patients, some had the accessory pathway in which antegrade ERP was shorter than 250 msec. They may result in rapid ventricular conduction over the accessory pathway when atrial fibrillation develops.     

Syncope in the Wolff-Parkinson-White Syndrome: Incidence and Electrophysiologic Correlates

Syncope in the patient with Wolff-Parkinson-White (WPW) syndrome raises the specter of rapid tachyarrhythmias and the possibility of sudden cardiac death. We reviewed the records of 55 consecutive WPW patients referred for electrophysiologic evaluation of known or suspected arrhythmias to determine the incidence and significance of syncope. Twelve patients (22.6%) reported the occurrence of at least one episode of syncope. In eleven (20%) of these, syncope was preceded by rapid palpitations. Forty-three patients (77.4%) had no syncopal episodes. These two groups did not differ significantly with regard to age, sex, presence of associated cardiac or neurologic disease, drug history or accessory pathway location. There was no significant difference in cycle length of reciprocating tachycardia (syncope = 295.6 ± 59.8 vs non-syncope = 334.5 ± 59.6 ms, p < .5), shortest R-R intervals between preexcited beats (260 ± 78.6 vs 246.7 ± 55.4 ms, p < .5) and average R-R interval (364.4 ± 37.9 vs 367.4 ± 77.5 ms, p < .5) measured during atrial fibrillation. The anterograde effective refractory period of the accessory pathway (292.1 ± 31.9 vs 299 ± 58.1 ms, p < .5) and the shortest cycle length with 1:1 conduction over the accessory pathway (306.7 ± 75 vs 289.1 ± 77.5 ms, p < .5) similarly did not differ. We conclude that syncope occurs in approximately 20% of patients with the Wolff-Parkinson-White syndrome referred for assessment of tachycardia. Patients with syncope do not have distinct clinical features or a more malignant electrophysiologic profile, suggesting that other extracardiac factors may play an important roe in the genesis of syncope in this group.     

Atrial fibrillation with a very rapid ventricular response as the first clinical arrhythmia in a 76-year-old man

The interest of electrohysiological study for the prognostic evaluation of asymptomatic Wolff-Parkinson-White (WPW) syndrome remains controversial. We report the case of an asymptomatic 67-year-old man without heart disease in whom a type A WPW syndrome was noted. Because the WPW was unchanged during exercise testing, transesophageal EPS was performed. In basal state, 1/1 conduction through the Kent bundle was noted up to a rate of 210 beats/min. After infusion of 30 microg of isoproterenol, atrial pacing was associated with a 1/1 conduction throughout the Kent bundle at a rate at 300 beats/min and induced rapid atrial fibrillation which was stopped by flecainide. No treatment was indicated. Nine years later, at age 76, the patient developed syncope related to rapid atrial fibrillation requiring cardioversion. In conclusion, the occurrence of a potentially lethal supraventricular tachyarrhythmia in a previously asymptomatic patient with WPW syndrome might be encountered in elderly patients. Transesophageal electrophysiological evaluation is a useful means to predict this risk.     

Should Radiofrequency Current Ablation be Performed in Asymptomatic Patients with the Wolff-Parkinson-White Syndrome?

The exiting new method of ablation of accessory pathways using radiofrequency current applied by catheters will dramatically change our therapeutic decisions in these patients in the near future. This brief survey reviews the existing literature about the risk of the disease as well as of the procedure of catheter ablation. From these data, the risk of sudden death appears to be extremely low in asymptomatic Wolff-Parkinsan-White (WPW) individuals. Side effects of catheter ablation may result from the invasive procedure as well as from radiation exposure (the latter to the patienl as well as to operating physicians). While the complication rate in experienced centers is extremely low, a multicenter registry of the success and complication rate is urgently needed in view of the many centers starting with catheter ablation. Based on a subjective benefit-to-risk analysis, asymptomatic WPW individuals should be offered catheter ablation only under special circumstances (high risk profession, athletes, family history of sudden death). On the other hand, catheter ablation need not be and should not be considered generally in asymptomatic individuals with WPW pattern. Finally, this author cannot imagine that the energy, time, and money spent for mass screening and eventual catheter ablation of asymptomatic WPW individuals with its attending risks can be outweighed by the potential benefits for these asymptomatic individuals.     

1例儿童无症状预激综合征的循证治疗

目的为1例无症状预激综合征儿童患者循证制定治疗方案。方法针对无症状预激综合征患儿是否需要进行预防性射频消融的问题，以“asymptomatic WPW syndrome”为检索词，全面检索Cochrane图书馆（2007年第3期）、MEDLINE（1981—2007）、OVID ACP Journal Club（1991—2007）、BM JClinical Evidence（1999～2007）以及美国国家指南交换中心（1998～2007），获取并评价相关的系统评价、随机对照试验、临床对照试验证据及治疗指南，并将最佳证据用于临床治疗。结果从MEDLINE检索到2篇随机对照试验，结果表明：高危对照组与消融组相比，心律失常事件发生显著增加，高危对照组中多旁道患者比单旁道患者心律失常事件发生显著增加。据此，我们结合医生经验和家长意愿，针对该例患者电生理检查示右侧显性旁道和左侧隐匿性旁道，进行预防性射频消融治疗。出院至今已12个月，未再出现心血管方面的并发症。结论对高危无症状预激综合征患儿进行预防性射频消融安全、有效。     

Comparison of Isoproterenol and Exercise Tests in Asymptomatic Subjects with Wolff-Parkinson-White Syndrome

In order to evaluate the effects of increases of sympathetic tone in ventricular response during atrial fibrillation and in the relationship between the accessory pathway effective refractory period (ERP) and ventricular rate during atrial fibrillation, 20 male subjects, aged 19 +/- 6 years, were studied electrophysiologically in basal conditions, after isoproterenol infusion (2-4 micrograms/min) and during submaximal bicycle exercise test, at a constant workload equal to that which increases the sinus rate to the same extent (140 beats/min) induced by isoproterenol infusion. Accessory pathway ERP was evaluated at the same driven rate (150 beats/min) in both instances. In the control study as during both tests atrial fibrillation paroxysms were induced by burst stimulation. In control conditions the rate increase from 100 to 150 beats/min induced a reduction of accessory pathway ERP from 266 +/- 27 msec to 244 +/- 22 msec (P less than 0.005). At the same driven rate of 150 beats/min, isoproterenol infusion and exercise test induced a more marked shortening of accessory pathway ERP to 211 +/- 28 msec (P less than 0.005) and to 214 +/- 29 msec (P less than 0.005), respectively. Atrial fibrillation paroxysms lasting more than 10 seconds were induced in 20/20 cases in the control study, in 15/20 during isoproterenol infusion and in 13/19 cases during exercise test. The shortest cycle length during atrial fibrillation was reduced from a basal value of 253 +/- 72 msec to 204 +/- 27 msec (P less than 0.05) during isoproterenol infusion and to 236 +/- 32 msec (NS) during exercise test.(ABSTRACT TRUNCATED AT 250 WORDS)     

Atrial and Ventricular Vulnerability in a Patient with the Wolff-Parkinson-White Syndrome

An electrophysiologic study was carried out in a patient with the Wolff-Parkinson-White syndrome and a history of spontaneous atrial fibrillation but with no evidence of organic cardiac disease. A single induced premature ventricular depolarization resulted in ventricular tachycardia followed by ventricular fibrillation. Similarly, atrial pacing or premature atrial stimulation resulted in frequent episodes of atrial fibrillation or flutter, The atrial and ventricular effective refractory periods were 180 ms and < 160 ms, respectively, at a driven cycle length of 480 ms. Intravenous administration of procainamide resulted in lengthening of the refractory periods and failure to induce either atriaJ or ventricular arrhythmias with pacing. In most patients with enhanced atrioventricular nodal or accessory atrioventricular nodal bypass, the mechanism of ventricular tachycardia is related to an inordinately rapid ventricular response during supraventricular arrhythmias. In our patient, a unique mechanism was apparent: atrial and ventricular vulnerability to fibrillation was associated with extremely short myocardial effective refractory periods. The relationship of this finding to sudden cardiac death bears further study.     

Wolff-Parkinson-White syndrome concomitant with asymptomatic Brugada syndrome

A 29-year-old man was referred for electrophysiological testing and radiofrequency ablation because of repeated episodes of palpitation over 2 years. A 12-lead electrocardiogram during sinus rhythm showed manifest Wolff-Parkinson-White syndrome and during palpitation showed narrow QRS tachycardia at a rate of 213 beats/min. Following successful radiofrequency ablation of the left anterolateral accessory pathway, sustained atrial fibrillation was induced by atrial extrastimulation. Cibenzoline (2 mg/kg body weight) was injected to terminate atrial fibrillation. ST-T segment elevation in the right precordial leads was observed following cibenzoline administration. Ventricular fibrillation was reproducibly induced by ventricular extrastimuli (S1: 600 ms, S2: 220 ms, S3: 210 ms).     

The Use of Atrial Pacing to Evaluate Patients with Definite or Suspected Wolff-Parkinson-White Syndrome

Four patients with definite or suspected WPW syndrome are presented in order to show that valuable clinical information can be obtained via simple atrial pacing. In three cases with a questionable resting ECG, atrial pacing produced pathognomonic changes in the QRS complex, establishing the diagnosis of WPW syndrome. In the fourth case, atrial pacing provoked the associated tachyarrhythmia, which had not previously been documented. In all four cases, functional properties of the accessory pathway could be assessed, and in three cases, the induction of atrial fibrillation allowed estimation of the risk of ventricular fibrillation. For evaluating patients with definite or suspected WPW syndrome, the technique of atrial pacing is recommended as an alternative to sophisticated electrophysiological studies which are costly and require special expertise and equipment. Atrial pacing is easier, cheaper, and less traumatic, and for many patients will provide most, if not all, the necessary information.     

Alterations of Orthodromic Circus Movement Tachycardia by Dual Atrioventricular Nodal Pathways in a Patient with Wolff-Parkinson-White Syndrome

In a patient with a left sided accessory pathway (AP) three different types of orthodromic circus movement tachycardia were observed; (1) narrow QRS complex tachycardia with a stable cycle length (CL); (2) wide QRS complex tachycardia with a functional bundle branch block ipsilateral to the AP, which, paradoxically, had a shorter CL. The decrease in CL was due to a decrease of the AH interval; and (3) narrow QRS complex tachycardia with alternating CL, due to alternations of the AH interval. These phenomena were attributed to a concomitant dual airioventricular (AV) node, which was eventually proven after successful catheter ablation of the AP.     

Utility of Adenosine Administration During Intraoperative Mapping in A Patient with the Wolff-Parkinson-White Syndrome

Adenosine is an endogenous nucleoside that is administered intravenously and has potent chronotropic and dromotropic effects. This drug is distinguished from verapamil by its very short half-life. This makes it an ideal agent for use in the operating room where long lasting electrophysiological effects may not be desirable. A 61-year-old man with preexcited atrial fibrillation was referred for surgical ablation of his accessory pathway. Preexcitation was minimal or absent on arrival in the operating room. Intravenous adenosine was given causing AV nodal block, and resulted in marked preexcitation, thus allowing computerized mapping to localize the site of the accessory pathway. Adenosine may be a useful agent for rapid and precise localization of accessory pathway(s) in a select group of patients with minimal preexcitation at the time of surgery. Its short half-life allows additional mapping without sustained electrophysiological effects on the AV node, or accessory pathway.     

Reproducibility of Transesophageal Pacing in Patients with Wolff-Parkinson-White Syndrome

The purpose of this study was to assess, in patients with ventricular preexcitation, the time dependent physiological variation of antegrade conduction properties in the AV node and in accessory pathways (Aps) as a function of autonomic tone variation induced by posture and physical effort, using noninvasive transesophageal atrial pacing. In 74 WPW patients (mean age 21.31 ± 9.46 yrs), AV node and Kent antegrade effective refractory periods (at pacing cycle lengths 600. 400, and 320 ms), Wenckebach point, shortest preexcited ER intervals during sustained atrial fibrillation (AF) or atrial pacing, as well as the inducibility of AV reentry tachycardia (A VRT) and AF/flutter (AFL) were assessed. AH measurements were carried out at rest, in supine and upright positions, and during effort. A second study was carried out approximately 3 months after the first study. The coefficients of variation (CVs) and reproducibility (CRs) were calculated. For each parameter, the differences between the mean of the two studies were not statistically significant. The CVs and CRs ranged between 0.4% and 4% and between 2 and 28 ms, respectively. AF was induced in 40 (54%) of 74 patients at the first study and in 30 (40.5%) of 74 patients at the second study. AVRT was induced in 33 (45%) of 74 patients at the first study and in 38 (51.3%) of 74 patients at the second study. The reproducibility was 45% for AF/AFL and 65% for reentry tachycardia. Transesophageal atrial pacing is a reliable method for noninvasive reproducible evaluation of ante- grade electroph ysiological properties of both the AV node and APs in WPW patients. However, the effect of autonomic balance variation has to be taken into account and precisely defined because it may significantly affect the inducibility of supraventricular arrhythmias and the estimation of the absolute values of the vulnerable parameters.     

Procainamide-Induced Incessant Supraventricular Tachycardia in the Wolff-Parkinson-White Syndrome

A patient with the Wolff-Parkinson-White syndrome presented with incessant orthodromic atrioventricular tachycardia following initiation of procainamide therapy. This finding was repeatedly documented both clinically as well as during electrophysiologic testing. Escape atrial complexes, which occurred following junctional premature complexes, failed to initiate tachycardia in the control state but tachycardia was always reinitiated by an identical escape sequence after procainamide. In addition, the tachycardia persisted and was repeatedly spontaneously reinitiated for prolonged periods after procainamide. The pro-arrhythmic effects of procainamide may be explained on the basis of both its vagolytic action on the atrioventricular node as well as by prolongation of refractoriness in the accessory pathway. These observations add to the literature on pro-arrhythmic effects of commonly used antiarrhythmic drugs.     

A Comparison of Intravenous Propafenone and Flecainide in the Treatment of Tachycardias Associated with the Wolff-Parkinson-White Syndrome

We compared the electrophysiological effects of intravenous propafenone andflecainide on accessory pathway conduction by a randomized crossover study in 16 patients with Wolff-Parkinson-While syndrome. The antegrade refractory period of the pathway increased from 256 ± 18 msec at baseline to 288 ± 13 msec on propafenone (P < 0.05) find to 296 ± 2 7 msec on flecainide (P = 0.075). The minimum preexcited HR interval during atrial fibrillation or incremental atrial pacing was prolonged from 225 ± 37 msec to 262 ± 22 msec by propafenone (P < 0.05) and to 301 ± 31 msec by flecainide (P < 0.005). The prolongation was significantly greater with flecainide than propafenone (P < 0.05). Both drugs increased tachycardia cycle length (TCL) from 310 ± 35 msec to 354 ± 37 msec (propafenone P < 0.005) and to 352 ± 37 msec (flecainide P < 0.01). Both propafenone and flecainide blocked antegrade conduction in the pathway in five patients. Both drugs rendered atrial fibrillation noninducifale in seven patients and orthodromic tachycardia nonindudble in five patients. Conclusions: (1) Fiecainide causes a greater prolongation of minimum preexcited RR interval than propafenone; (2) There is no significant difference between propafenone and flecainide on the inducibility of arrhythmias, TCL, or incidence of antegrade conduction block.     

Right Atrial Diverticulum Presenting as Wolff-Parkinson-White Syndrome

A 7-year-old male presenting with Wolff-Parkinson-White syndrome and tachycardia was suspected by echocardiographic and magnetic resonance imaging evaluation to have an associated pericardial cyst anterior to the right atrium and ventricle. Electrophysiological evaluation demonstrated short antegrade and retrograde accessory connection refractory periods, with inducible orthodromic atrioventricular reentrant tachycardia. Surgical observation revealed a rare congenital right atrial diverticulum bridging the anterior right atrioventricular groove, with the functional accessory connection lateralized to the medial aspect of this structure. Endocardial and epicardial incisions and cryolesions placed along the anterior right atrioventricular groove initially appeared successful, but preexcitation recurred within 4 weeks postoperatively.     

Electrocardiography in the patient with the Wolff-Parkinson-White syndrome: diagnostic and initial therapeutic issues

The Wolff-Parkinson-White syndrome (WPW), estimated to occur in approximately 0.1% to 3% of the general population, is a form of ventricular preexcitation involving an accessory conduction pathway. The definition of WPW relies on the following electrocardiographic features: (1) a PR interval less than 0.12 seconds (2) with a slurring of the initial segment of the QRS complex, known as a delta wave, (3) a QRS complex widening with a total duration greater than 0.12 seconds, and (4) secondary repolarization changes reflected in ST segment-T wave changes that are generally directed opposite (discordant) to the major delta wave and QRS complex changes. The accessory pathway bypasses the atrioventricular (AV) node, creating a direct electrical connection between the atria and ventricles. The majority of patients with preexcitation syndromes remain asymptomatic throughout their lives. When symptoms do occur they are usually secondary to tachyarrhythmias; the importance of recognizing this syndrome is that these patients may be at risk to develop a variety of supraventricular tachyarrhythmias which cause disabling symptoms and, in the extreme, sudden cardiac death. The tachyarrhythmias encountered in the WPW patient include paroxysmal supraventricular tachycardia (both the narrow QRS and wide QRS complex varieties), atrial fibrillation, atrial flutter, and ventricular fibrillation. Diagnostic and urgent, initial therapeutic issues based on initial electrocardiographic information are presented via 5 illustrative cases.     

The different electrophysiological characteristics in children with Wolff-Parkinson-White syndrome between those with and without atrial fibrillation

Atrioventricular reciprocating tachycardia (AVRT) is known to be the most common supraventricular tachycardias in childhood. Because AF with rapid ventricular response may degenerate to ventricular fibrillation through conduction of accessory pathways (APs), it can be potentially life-threatening in some pediatric patients with WPW syndrome. However, information about WPW syndrome children associated with AF is limited. The purpose of this study was to investigate the specific electrophysiological characteristics in pediatric patients with WPW syndrome and AF. From July 1992 to February 2002, 51 pediatric patients with manifest WPW syndrome and documented AVRT underwent electrophysiological study and radiofrequency catheter ablation. In these patients, two (4%) were found to have several spontaneous episodes of AF recognized on 12-lead standard ECG or 24-hour Holter monitoring. Eleven (22%) patients had AF induced by rapid atrial pacing during the baseline procedure of electrophysiological study. The children with manifest WPW syndrome were divided into two groups: those with AF (group 1; n = 11) consisted of seven male and four female children (mean age 15 +/- 3 years, range 10-18), and those without AF (group 2; n = 40) consisted of 22 boys and 18 girls (mean age 16 +/- 3 years, range 7-18). The study excluded a patient who had Ebstein's anomaly associated with moderate tricuspid regurgitation and right atrial enlargement. The onset and duration of symptoms were not significantly different between the two groups. Comparing the electrophysiological characteristics, the atrial effective refractory period (ERP) was shorter in WPW syndrome children with AF (170 +/- 36 vs 190 +/- 38 ms, P = 0.041). This study demonstrated that the pediatric WPW syndrome patients with AF had different electrophysiological characteristics from those without AF.     

The Geriatric Patient's Fears About Death

Several studies show that elderly patients are no more afraid of death than patients in any other age group. They do talk about death and have some distinct fears not so much about the event of death as of the process of dying.     

Ablation of a Left-Sided Free-Wall Accessory Pathway by Percutaneous Catheter Application of Radiofrequency Current in a Patient with the Wolff-Parkinson-White Syndrome

A case is presented of a 20-year-old woman with a history of three episodes of syncope within the last 4 years, which was caused by a rapid ventricular response to atrial fibrillation via a left-sided posterior accessory pathway. A variety of antiarrhythmic agents had failed to control the arrhythmia. Using a novel dual catheter approach, with one catheter in the coronary sinus and an adjacent catheter in the left ventricle close to the mitral annulus, accessory pathway conduction was successfully interrupted by two radio-frequency current applications between the tip electrodes of the two catheters. During follow-up, 12-lead electrocardiograms have been normal and the patient has been asymptomatic.