Diagnosis and cure of the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardias during a single electrophysiologic test

Novel pacing maneuvers for mapping the upstream insertion of unidirectional accessory pathways

BACKGROUND

Anatomic characterization of unidirectional accessory pathways (APs) is inherently limited to the localization of the downstream insertion site. The inability to define the full anatomic course of unidirectional pathways can limit the safety and effectiveness of ablation in the setting of complex pathways, slanted pathways, unstable catheter positioning at downstream insertions, or insertions near the conduction system.

OBJECTIVE

We aimed to develop novel pacing maneuvers to localize upstream insertions of unidirectional APs.

METHODS

Two methods were evaluated: localizing the shortest transit time from roving pacing sites to a fixed reference in the opposite chamber (upstream transit mapping); and identifying the site at which the latest atrial or ventricular extrastimulus reset atrioventricular reciprocating tachycardia (late reset mapping). Unidirectional APs were included to test utility and feasibility of the techniques, and bidirectional APs were included to test anatomic accuracy.

RESULTS

A total of 13 patients were included, 8 unidirectional APs and 5 bidirectional APs. Blind side mapping was successfully performed in all cases and showed excellent spatial correlation to conventional mapping methods (mean, 4.2 mm; SD, 1.3 mm) as well as to the site of successful ablation (mean, 2.5 mm; SD, 2.9 mm). The upstream transit mapping method was critical for successful ablation after conventional techniques proved inadequate in 2 cases.

CONCLUSION

Two novel methods, upstream transit mapping and late reset mapping, were used to localize the previously unmappable upstream insertions of unidirectional pathways. These methods expand the diagnostic toolbox to facilitate successful ablation in challenging cases.

Prevalence and characteristics of atrioventricular nodal reentrant tachycardia with a bystander concealed nodoventricular/nodofascicular pathway

BACKGROUND

The concealed nodoventricular/nodofascicular (NV/NF) pathway is mostly a bystander, retrograde bypass tract connecting the right ventricle/right bundle branch (RBB) and slow pathway that is observed in patients with atrioventricular nodal reentrant tachycardia (AVNRT). However, its prevalence and characteristics in response to pacing maneuvers have not been fully evaluated.

OBJECTIVE

This study investigated the prevalence and characteristics of AVNRT with a bystander NV/NF pathway.

METHODS

We retrospectively reviewed 153 consecutive patients undergoing catheter ablation of AVNRT. After exclusion of 52 patients with inadequate electrophysiologic data, 101 patients composed the study population.

RESULTS

Three patients (3.0%) had bystander concealed NV/NF pathways, all of which were connected to the slow pathway. The tachycardia was typical slow pathway/fast pathway AVNRT in 2 patients and atypical fast pathway/slow pathway AVNRT in 1 patient. In all cases, His-refractory ventricular extra-stimuli (VES) reset the AVNRTs with delay through the NV/NF pathways. Ventricular overdrive pacing (VOP) in the early phase also reset the AVNRT with delay. Earlier VES and middle phase of VOP did not reset the tachycardia, and further earlier VES and late phase of VOP reset the tachycardia with advance through the RBB-His conduction.

CONCLUSION

A bystander NV/NF pathway was not rare in patients with AVNRT. The VES and VOP for the AVNRTs with the bystander NV/NF pathways were characterized by the 2-phase resetting phenomenon: initial transient resetting with delay through the NV/NF pathway, and late resetting with advance through the RBB-His conduction.

Combining conventional technique with fluoroscopy integration module in accessory pathway ablation

INTRODUCTION

Accessory pathway (AP) ablation is a straightforward approach with high success rates, but the fluoroscopy time (FT) is significantly longer in conventional technique. Electroanatomical mapping systems (EMS), reduce the FT, but anatomical and activation mapping may prolong the procedure time (PT). The fluoroscopy integration module (FIM) uses prerecorded fluoroscopy images and allows ablation similar to conventional technique without creating an anatomical map. In this study, we investigated the effects of combining the FIM with traditional technique on PT, success, and radiation exposure.

METHODS

A total of 131 patients who had undergone AP ablation were included in our study. In 37 patients, right and left anterior oblique (RAO-LAO) images were acquired after catheter placement and integrated with the FIM. The ablation procedure was then similar to the conventional technique, but without the use of fluoroscopy. For the purpose of acceleration, anatomical and activation maps have not been created. Contact-force catheters were not used. 94 patients underwent conventional ablation using fluoroscopy only.

RESULTS

FIM into AP ablation procedures led to a significant reduction in radiation exposure, lowering FT from 7.4 to 2.8 min (p < .001) and dose-area product from 12.47 to 5.8 μGym² (p < .001). While the FIM group experienced a reasonable longer PT (69 vs. 50 min p < .001). FIM reduces FT regardless of operator experience and location of APs CONCLUSION: Combining FIM integration with conventional AP ablation offers reduced radiation exposure without compromising success rates and complication.

Contemporary procedure characteristics and outcomes of accessory atrioventricular pathway ablations in an integrated community-based health care system using a tiered approach

BACKGROUND

Since the early descriptions of large series of accessory atrioventricular pathway ablations in adults and adolescents over 20 years ago, there have been limited published reports based on more recent experiences of large referral centers. We aimed to characterize accessory pathway distribution and features in a large community-based population that influence ablation outcomes using a tiered approach to ablation.

METHODS

Retrospective analysis of 289 patients (age 14-81) who underwent accessory ablation from 2015-2019 was performed. Pathways were categorized into anteroseptal, left freewall, posteroseptal, and right freewall locations. We analyzed patient and pathway features to identify factors associated with prolonged procedure time parameters.

RESULTS

Initial ablation success rate was 94.7% with long-term success rate of 93.4% and median follow-up of 931 days. Accessory pathways were in left freewall (61.6%), posteroseptal (24.6%), right freewall (9.6%), and anteroseptal (4.3%) locations. Procedure outcome was dependent on pathway location. Acute success was highest for left freewall pathways (97.1%) with lowest case times (144 ± 68 min) and fluoroscopy times (15 ± 19 min). Longest procedure time parameters were seen with anteroseptal, left anterolateral, epicardial-coronary sinus, and right anterolateral pathway ablations.

CONCLUSIONS

In this community-based adult and adolescent population, majority of the accessory pathways are in the left freewall and posteroseptal region and tend to be more easily ablated. A tiered approach with initial use of standard ablation equipment before the deployment of more advance tools, such as irrigated tips and 3D mapping, is cost effective without sacrificing overall efficacy.

Segmental septal dyskinesia associated with an accessory pathway and preexcitation in two Golden Retriever dogs

Ventricular preexcitation secondary to anterograde conduction through an accessory pathway was diagnosed in two Golden Retriever dogs. Both dogs demonstrated similar segmental myocardial thinning and systolic dyskinesia of the basal interventricular wall on echocardiography. These changes are widely recognised in people with ventricular preexcitation but have not been previously described in dogs. Ventricular preexcitation should be considered as a potential cause for segmental wall motion abnormalities in these two dogs.

A New Scoring System Detecting the Supraventricular Tachycardia Inducibility and Radiofrequency Ablation With High Specificity in Electrophysiological Study

Aim

The relationship between arrhythmia induction and ablation with palpitation characteristics has been demonstrated in electrophysiological study (EPS) patients. However, there is insufficient data on palpitation characteristics and their sensitivity and specificity. We aimed to identify the relationship between scoring composed of palpitation characteristics with the supraventricular tachycardia (SVT) induction and the success rate of the procedure.

Method

A total of 119 patients, diagnosed as paroxysmal supraventricular tachycardia (PSVT) by electrocardiography, rhythm Holter or symptoms, and underwent EPS, were enrolled in the study. A psychiatrist administered the Hospital Anxiety and Depression Score (HADS) questionnaire.

Results

In SVT induced group, palpitation duration (p = 0.048), palpitation spread to neck (p 0.004), responsiveness to medication (p = 0.008), induction with stress (p = 0.007), admission to emergency (p = 0.021) and documented PSVT (p = 0.017) were more common. Atropine administration (p = 0.001) was higher, and the Wenckebach cycle length (p < 0.001) was longer in the non-induced arrhythmia group. The presence of dual AV pathways was higher in SVT induced group (p = 0.002). There were no differences between groups in terms of anxiety score (p = 0.192), depression score (p = 0.730), and total psychiatric results (p = 0.280) in the HADS questionnaire. In scoring designed by the palpitation characteristics, the score of four and over predicted SVT induction with 63.6% sensitivity and 92.5% specificity. Radio-frequency ablation (RFA) was performed succesfully in 82.1% of patients with a score of ≥4.

Conclusion

Supraventricular tachycardia induction score obtained from the palpitations characteristics and arrhythmia documentation can be useful in predicting the induction of SVT and the success of RFA.

A study of narrow QRS tachycardia with emphasis on the clinical features, ECG, electrophysiology/radiofrequency ablation

Aim: Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) are the most common forms of paroxysmal regular supraventricular tachycardias. Materials & methods: The clinical, ECG and electrophysiological findings of 121 patients with narrow QRS tachycardia were evaluated prospectively. Results: A total of 75 (62%) of the patients had AVNRT while 46 (38%) had AVRT. Pounding sensation in the neck (40 vs 15.2%; p = 0.004), presynope (26.7 vs 56.5%; p = 0.001) identifiable P wave after QRS complex (25.3 vs 73.9%; p = 0.001), pseudo r'/s waves (45.3 vs 4.3%; p = 0.001), limb leads ST-T changes (34.7 vs 60.9%; p = 0.004) were the significant changes observed. A total of 94.7% of AVNRT and 87% of AVRT could be diagnosed correctly considering both clinical and ECG criteria. Conclusion: Pounding sensation in the neck and presyncope along with ECG features like identifiable P wave after QRS complex, pseudo r'/s waves and limb lead ST-T changes very accurately differentiate AVNRT and AVRT.

Outcomes of ablation in Wolff-Parkinson-White-syndrome: Data from the German Ablation Registry

AIMS

Catheter ablation is recommended for symptomatic WPW-syndrome. Commonly perceived low recurrence rates were challenged recently. We sought to identify patient strata at increased risk.

METHOD

Of 12,566 patients enrolled at 52 German Ablation Registry sites from 2007 to 2010, 789 were treated for WPW-syndrome. Patients were included for symptomatic palpitations and tachycardia documentation. Follow-up duration was one year. Overall complications were defined as serious, access-related, and ablation-related. We adjudicated WPW-recurrence for re-ablation during follow-up. Risk strata included: admission for repeat ablation at registry entry; accessory pathway localization; antiarrhythmic medical treatment before the ablation.

RESULTS

WPW-syndrome patients were 42.8 ± 16.2 years on average; 39.9% were women. A majority of 95.9% was symptomatic; in 84.4%, a tachycardia was documented. Seventy-six (9.6%) patients presented for repeat procedures. Accessory pathways were located in the left atrium (71.4%), right atrium (21.1%), septum (4.4%), or coronary sinus diverticula (2.1%). Prior antiarrhythmic medication was used in 43.7% of patients. No serious events occurred. The overall complication rate was 2.5% (ablation related 1.2%, access-related 1.3%). Major determinants for complications were presentation for re-ablation as registry index procedure (6.9% vs 2.2%; p = 0.016) and septal pathway location (left 2.0% vs septal 9.1%, p = 0.014). The overall re-ablation rate was 9.7%. Usage of prior antiarrhythmic medication was associated with higher recurrence rates (12.2% vs. 7.6%; p = 0.035).

CONCLUSIONS

Patients at higher complication risk may be identified by repeat procedure and septal pathway location. Prior antiarrhythmic medication was associated with higher recurrence rates. Our findings may help improving peri-procedural patient management and information.

Left anterior descending coronary artery dissection during ventricular tachycardia ablation - case report

Fascicular left ventricular tachycardia (VT) is the second most frequent idiopathic left VT in the setting of a structurally normal heart. Catheter ablation is curative in most patients with low complication rates. We report a case of ostial left anterior descending coronary artery (LAD) occlusion during fascicular ventricular tachycardia ablation. Dissection was the most likely cause of LAD obstruction. To the authors' best knowledge, this is the first case reporting selective LAD dissection during electrophysiology study with no left main coronary artery (LMCA) affection.

Reflections on the early invasive clinical cardiac electrophysiology era through fifty manuscripts: 1967-1992

In 1967, researchers in The Netherlands and France independently reported a new technique, later called programmed electrical stimulation. The ability to reproducibly initiate and terminate arrhythmias heralded the beginning of invasive clinical cardiac electrophysiology as a medical discipline. Over the next fifty years, insights into the pathophysiologic basis of arrhythmias would transform the field into an interventional specialty with a tremendous armamentarium of procedures. In 2015, the variety and complexity of these procedures were major reasons that led to the recommendation for an increase in the training period from one year to two years. The purpose of this manuscript is to present fifty manuscripts from the early invasive clinical cardiac electrophysiology era, between 1967 and 1992, to serve as an educational resource for current and future electrophysiologists. It is our hope that reflection on the transition from a predominantly noninvasive discipline to one where procedures are commonly utilized will lead to more thoughtful patient care today and to inspiration for innovation tomorrow. In the words of the late Dr. Mark E. Josephson, "It is only by getting back to the basics that the field of electrophysiology will continue to grow instead of stagnate."

The coexistence of Wolff-Parkinson-White syndrome (WPW) and atrioventricular nodal reentrant tachycardia (AVNRT)

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common type of reentrant paroxysmal supraventricular tachycardia that occurs in the presence of dual AV nodal physiology. Wolff-Parkinson-White (WPW) syndrome is another type of supraventricular tachycardia characterized by short PR intervals, delta waves and wide QRS complexes on the surface electrocardiogram (ECG), reflecting atrioventricular pre-excitation. Uncommonly, AV nodal reentry and accessory pathways can coexist. In this case report, we present a patient who had frequent episodes of palpitation and syncope and recently presented to the emergency department (ED) with the complaint of dizziness. We performed successful radiofrequency (RF) catheter ablation of mitral annulus posterolateral accessory pathway and AVNRT which was the cause of the second tachycardia induced during the same session.

Asymptomatic Ventricular Pre-excitation: Between Sudden Cardiac Death and Catheter Ablation

Debate about the best clinical approach to the management of asymptomatic patients with ventricular pre-excitation and advice on whether or not to invasively stratify and ablate is on-going. Weak evidence about the real risk of sudden cardiac death and the potential benefit of catheter ablation has probably prevented the clarification of action in this not infrequent and sometimes conflicting clinical situation. After analysing all available data, real evidence-based medicine could be the alternative strategy for managing this group of patients. According to recent surveys, most electrophysiologists invasively stratify. Based on all accepted risk factors - younger age, male, associated structural heart disease, posteroseptal localisation, ability of the accessory pathway to conduct anterogradely at short intervals of ≤250 milliseconds and inducibility of sustained atrioventricular re-entrant tachycardia and/or atrial fibrillation - a shared decisionmaking process on catheter ablation is proposed.

A clinical approach to arrhythmias revisited in 2018 : From ECG over noninvasive and invasive electrophysiology to advanced imaging

Understanding arrhythmias and their treatment is not always easy. The current straightforward approach with catheter ablation and device therapy is an amazing achievement, but does not make management of underlying or other cardiac disease and pharmacological therapy unnecessary. The goal of this paper is to describe how much of the knowledge of the 1980s and early 1990s can and should still be applied in the modern treatment of patients with arrhythmias. After an introduction, this review will focus on paroxysmal atrial fibrillation and a prototype of ‘idiopathic’ ventricular arrhythmias, two diseases with a striking similarity, and will discuss the arrhythmogenesis. The ECG continues to play an important role in diagnostics. Both diseases are associated with a structurally normal heart; the autonomic nervous system plays an important role in triggering arrhythmias at both the atrial and ventricular level.

Catheter ablation of accessory pathway: 14-year trends in utilization and complications in adults in the United States

BACKGROUND

The aim of this study was to determine the temporal trends in utilization of catheter ablation of accessory pathways in the United States.

METHODS

All patients from the Nationwide Inpatient Sample (NIS) ≥18years of age with a primary diagnosis of anomalous atrioventricular excitation syndrome (International Classification of Diseases, Ninth Edition, Clinical Modification [ICD-9-CM] code 426.7) were included in the study. Patients who underwent catheter ablation were identified using ICD-9-CM procedure code 37.34. Patients with a concomitant diagnosis of atrial fibrillation, atrial flutter, atrial tachycardia or ventricular arrhythmias were excluded from the analysis. Annual hospital volume was identified using unique hospital identification number and was divided into tertiles for further analysis.

RESULTS

A total of 11,601 catheter ablations for anomalous atrioventricular excitation syndrome were studied from 1998 to 2011. The mean length of stay was 1.8days (median 1day). The utilization trends of accessory pathway ablation have steadily declined from 3.9 ablation procedures/million US population in 1998-1999 to 2.5 ablation procedures/million US population in 2010-2011. The second tertile (adjusted OR 0.41; 95% CI 0.20-0.83, p=0.01) and third tertile (adjusted OR 0.39; 95% CI 0.18-0.85, p=0.02) of hospital volume were associated with reduction in cardiac complications as compared to first tertile of hospital volume. Advanced age (OR 1.02, 95% CI 1.01-1.04, p=0.002) was independent predictor of cardiac complications. There were no in-hospital deaths.

CONCLUSION

Despite decline in ablation trends, it still remains a relatively safe procedure associated with low morbidity and no mortality.

Focal atrial tachycardia originating from the septal mitral annulus: electrocardiographic and electrophysiological characteristics and radiofrequency ablation

AIMS

This study sought to investigate electrocardiographic characteristics, electrophysiological features, and radiofrequency ablation in patients with focal atrial tachycardia (AT) originating from the septal mitral annulus.

METHODS AND RESULTS

In 13 patients with AT originating from the septal mitral annulus, activation mapping was performed to identify the earliest activation site. Successful ablation was performed through either a transseptal (n = 12) or a retrograde aortic approach (n = 1). As confirmed by electrogram recordings, fluoroscopy, and three-dimensional (3D) mapping, successful ablation sites were located in the anterior paraseptal, mid- to anteroseptal, and posterior septal mitral annulus in eight, three, and two patients, respectively. Foci for all locations demonstrated a negative/positive appearance in lead V1. Mapping in the right atrium demonstrated that the earliest right atrial activation was near the septum (His-bundle region or proximal coronary sinus). The electrograms at the successful ablation sites were fractionated in 9 patients, and presented with an atrial:ventricular ratio of <1 in all 13 patients. There were no complications in any patients and long-term success was achieved in 12 of 13 patients during the 23 ± 6 months following ablation.

CONCLUSION

The area surrounding the septal mitral annulus, most commonly the anterior paraseptal, is an unusual, but important site of origin for focal AT, which is associated with a distinctive P-wave morphology and atrial endocardial activation sequence. Radiofrequency ablation of AT originating from the septal mitral annulus, through either a transseptal or a retrograde aortic approach appears to be safe and effective.

Radiofrequency Ablation to Prevent Sudden Cardiac Death

Radiofrequency ablation may prevent or treat atrial and ventricular arrhythmias. Since some of these arrhythmias are associated with sudden cardiac death, it has been hypothesized that ablation may prevent sudden death in certain cases. We performed a literature search to better understand under which circumstances ablation may prevent sudden death and found little randomized data demonstrating the long-term effects of ablation. Current literature shows that ablation clearly prevents symptoms of arrhythmia and may reduce the incidence of sudden cardiac death in select patients, although data does not indicate improved mortality. Ongoing clinical trials are needed to better define the role of ablation in preventing sudden cardiac death.

Biophysics and clinical utility of irrigated-tip radiofrequency catheter ablation

Catheter ablation by radiofrequency (RF) energy has successfully eliminated cardiac tachyarrhythmias. RF ablation lesions are created by thermal energy. Electrode catheters with 4-mm-tips have been adequate to ablate arrhythmias located near the endocardium; however, the 4-mm-tip electrode does not readily ablate deeper tachyarrhythmia substrate. With 8- and 10-mm-tip RF electrodes, ablation lesions were larger; yet, these catheters are associated with increased risk for coagulum, char and thrombus formation, as well as myocardial steam rupture. Cooled-tip catheter technology was designed to cool the electrode tip, prevent excessive temperatures at the electrode tip-tissue interface, and thus allow continued delivery of RF current into the surrounding tissue. This ablation system creates larger and deeper ablation lesions and minimizes steam pops and thrombus formation. The purpose of this article is to review cooled-tip RF ablation biophysics and outcomes of clinical studies as well as to discuss future technological improvements.

The history of the wolff-Parkinson-white syndrome

While Drs Wolff, Parkinson, and White fully described the syndrome in 1930, prior case reports had described the essentials. Over the ensuing century this syndrome has captivated the interest of anatomists, clinical cardiologists, and cardiac surgeons. Stanley Kent described lateral muscular connections over the atrioventricular (AV) groove which he felt were the normal AV connections. The normal AV connections were, however, clearly described by His and Tawara. True right-sided AV connections were initially described by Wood et al., while Öhnell first described left free wall pathways. David Scherf is thought to be the first to describe our current understanding of the pathogenesis of the WPW syndrome in terms of a re-entrant circuit involving both the AV node-His axis as well as the accessory pathway. This hypothesis was not universally accepted, and many theories were applied to explain the clinical findings. The basics of our understanding were established by the brilliant work of Pick, Langendorf, and Katz who by using careful deductive analysis of ECGs were able to define the basic pathophysiological processes. Subsequently, Wellens and Durrer applied invasive electrical stimulation to the heart in order to confirm the pathophysiological processes. Sealy and his colleagues at Duke University Medical Center were the first to successfully surgically divide an accessory pathway and ushered in the modern era of therapy for these patients. Morady and Scheinman were the first to successfully ablate an accessory pathway (posteroseptal) using high-energy direct-current shocks. Subsequently Jackman, Kuck, Morady, and a number of groups proved the remarkable safety and efficiency of catheter ablation for pathways in all locations using radiofrequency energy. More recently, Gollob et al. first described the gene responsible for a familial form of WPW. The current ability to cure patients with WPW is due to the splendid contributions of individuals from diverse disciplines throughout the world.

Radiofrequency ablation for pre-excitation syndromes and AV nodal re-entrant tachycardia

Radiofrequency catheter ablation for supraventricular tachycardia was introduced in 1990. Since then it has become the standard for definitive treatment of pre-excitation syndromes and atrioventricular re-entrant tachycardia. In general, catheter ablation of supraventricular tachycardia results in improved outcomes compared to pharmacologic treatment. Over 95% of patients will be successfully treated with catheter ablation with less than a 5% chance of recurrence and <1% risk of major complications.

Radiofrequency ablation of cardiac arrhythmias: past, present and future

The treatment of cardiac arrhythmias has been revolutionized by the ability to definitively treat many patients with radiofrequency catheter ablation, rather than requiring lifelong medication. This review covers the history of how this has developed and the methods used currently and explores what the future holds for this rapidly evolving branch of Cardiology.

Wolff-Parkinson-White syndrome in young people, from childhood to young adulthood: relationships between age and clinical and electrophysiological findings

Purpose

The aim of the present study was to evaluate the characteristics of electrophysiologic studies (EPS) and radiofrequency ablation (RFA) performed in subjects aged less than 30 years with Wolff-Parkinson-White (WPW) syndrome, particularly pediatric patients under 18 years of age, based on our experience.

Methods

Two hundred and one consecutive patients with WPW syndrome were recruited and divided to 3 groups according to age: group 1, 6 to 17 years; group 2, 18 to 29 years; and group 3, 30 to 60 years. The clinical, electrophysiological, and therapeutic data for these patients were evaluated by a retrospective medical record review.

Results

A total of 73 (36%) of these patients were <30 years of age. Although there were more males than females in group 2 (male:female, 31:11), there was no sex difference in group 1 (male:female, 16:15). Left accessory pathway was detected less frequently in group 1 (32%, 10/31) than in group 2 (57%, 24/42) and group 3 (63%, 81/128) (P=0.023 and P=0.002, respectively).

Conclusion

The present study describes several different electrophysiological characteristics in children and adolescents with WPW syndrome. Therefore, when EPS and RFA are performed in children and adolescence with WPW syndrome, we recommend that these characteristics be considered.

The impact of age on the electrophysiological characteristics and different arrhythmia patterns in patients with Wolff-Parkinson-White syndrome

INTRODUCTION

Information about the impact of age on the electrophysiological characteristics of accessory pathways (APs) in patients with Wolff-Parkinson-White (WPW) syndrome remains limited.

METHODS AND RESULTS

A total of 1,885 consecutive patients (mean age 43 ± 17 years, male 61.5%) with WPW syndrome who were referred to the tertiary center for an electrophysiological study and radiofrequency catheter ablation were investigated. The patients were divided into 4 groups based on their age (Group 1: <20; Group 2: 20-39; Group 3: 40-59; Group 4: ≧60 years old). With age, more left-sided APs (53.2%, 67.7%, 71.7%, 75.7%, P < 0.001) and a longer duration of the arrhythmia (4.3 ± 2.8 years, 10.1 ± 7.0 years, 12.4 ± 10.9 years, 14.0 ± 12.4 years, P < 0.001) were noted. The incidence of concealed APs (53.5%, 53.0%, 57.8%, 60.9%, P = 0.01), and orthodromic atrioventricular (AV) reentrant tachycardia (92.4%, 94.2%, 96.5%, 96.3%, P = 0.023) increased with age. The tachycardia cycle length, antegrade (275.5 ± 42.2 ms, 286.7 ± 62.7 ms, 302.5 ± 66.5 ms, 315.2 ± 80.2 ms, P < 0.001) and retrograde AP effective refractory periods (APERPs) (254.0 ± 42.5 ms, 263.3 ± 51.8 ms, 274.5 ± 100.5 ms, 292.7 ± 57.0 ms, P < 0.001), atrial ERP, antegrade AV node effective refractory period (AVNERP), and ventricular effective refractory period (VERP) lengthened as the age increased. The incidence of decremental APs, multiple APs, and a catecholamine response were similar. The duration of the catheter ablation, total fluoroscopy time, acute success rate, complication rate, and incidence of a secondary procedure were similar between the different age groups.

CONCLUSION

The electrophysiological characteristics and pattern of the arrhythmic attack associated with the AP changed with age.