Frequency of recurrent atrial fibrillation after catheter ablation of overt accessory pathways

Arrhythmias with Bystander Accessory Pathways

An accessory pathway (AP) could manifest its presence exclusively during an orthodromic supraventricular tachycardia or with preexcitation during sinus rhythm (SR). The manifestations of the presence of an AP depend on its ability to conduct antegradely from atrium (A) to ventricle (V), retrogradely (V to A), or both. AP retrograde conduction is necessary to establish an atrioventricular reentrant tachycardia circuit. If an AP can only conduct antegradely, it will function as a bystander AV connection during independent arrhythmias. The correct diagnosis of this condition is very important, as it will determine the immediate and long-term management.

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

Effect of pulmonary vein isolation on atrial fibrillation recurrence after accessory pathway ablation in patients with Wolff-Parkinson-White syndrome

Background

Although successful ablation of the accessory pathway (AP) eliminates atrial fibrillation (AF) in some of patients with Wolff‐Parkinson‐White (WPW) syndrome and paroxysmal AF, in other patients it can recur.

Hypothesis

Whether adding pulmonary vein isolation (PVI) after successful AP ablation effectively prevents AF recurrence in patients with WPW syndrome is unknown.

Methods

We retrospectively studied 160 patients (102 men, 58 women; mean age, 46 ± 14 years) with WPW syndrome and paroxysmal AF who underwent AP ablation, namely 103 (64.4%) undergoing only AP ablation (AP group) and 57 (35.6%) undergoing AP ablation plus PVI (AP + PVI group). Advanced interatrial block (IAB) was defined as a P‐wave duration of >120 ms and biphasic (±) morphology in the inferior leads, using 12‐lead electrocardiography (ECG).

Results

During the mean follow‐up period of 30.9 ± 9.2 months (range, 3‐36 months), 22 patients (13.8%) developed AF recurrence. The recurrence rate did not differ in patients in the AP + PVI group and AP group (15.5% vs 10.5%, respectively; P = .373). Univariable and multivariable Cox regression analyses showed that PVI was not associated with the risk of AF recurrence (hazard ratio, 0.66; 95% confidence interval, 0.26‐1.68; P = .380). In WPW patients with advanced IAB, the recurrence rate was lower in patients in the AP + PVI group vs the AP group (90% vs 33.3%, respectively; P = .032).

Conclusions

PVI after successful AP ablation significantly reduced the AF recurrence rate in WPW patients with advanced IAB. Screening of a resting 12‐lead ECG immediately after AP ablation helps identify patients in whom PVI is beneficial.

Wolff-Parkinson-White syndrome: De novo variants and evidence for mutational burden in genes associated with atrial fibrillation

BACKGROUND

Wolff-Parkinson-White (WPW) syndrome is a relatively common arrhythmia affecting ~1-3/1,000 individuals. Mutations in PRKAG2 have been described in rare patients in association with cardiomyopathy. However, the genetic basis of WPW in individuals with a structurally normal heart remains poorly understood. Sudden death due to atrial fibrillation (AF) can also occur in these individuals. Several studies have indicated that despite ablation of an accessory pathway, the risk of AF remains high in patients compared to general population.

METHODS

We applied exome sequencing in 305 subjects, including 65 trios, 80 singletons, and 6 multiple affected families. We used de novo analysis, candidate gene approach, and burden testing to explore the genetic contributions to WPW.

RESULTS

A heterozygous deleterious variant in PRKAG2 was identified in one subject, accounting for 0.6% (1/151) of the genetic basis of WPW in this study. Another individual with WPW and left ventricular hypertrophy carried a known pathogenic variant in MYH7. We found rare de novo variants in genes associated with arrhythmia and cardiomyopathy (ANK2, NEBL, PITX2, and PRDM16) in this cohort. There was an increased burden of rare deleterious variants (MAF ≤ 0.005) with CADD score ≥ 25 in genes linked to AF in cases compared to controls (P = .0023).

CONCLUSIONS

Our findings show an increased burden of rare deleterious variants in genes linked to AF in WPW syndrome, suggesting that genetic factors that determine the development of accessory pathways may be linked to an increased susceptibility of atrial muscle to AF in a subset of patients.

Incidence, clinical, electrophysiological characteristics and outcomes of patients with Wolff-Parkinson-White syndrome and atrial fibrillation

AIMS AND OBJECTIVES

Atrial fibrillation (AF) with preexcitation can be life threatening. Our study evaluated the incidence, clinical features, electrophysiologic characteristics and outcomes of patients presenting with AF and fast ventricular rates associated with an antegrade conducting accessory pathway.

METHODS

Hospital data of patients who had undergone electrophysiology study and radiofrequency ablation for AF and Wolff-Parkinson-White (WPW) syndrome was retrospectively evaluated over 10 years and prospective data was further collected over 1 year. Out of 2876 patients undergoing electrophysiology study, 320 patients had manifest preexcitation on ECG. Forty one patients who had presented with AF and fast ventricular rates were included in the study.

RESULTS

Forty one (12.8%) patients out of 320 patients of WPW syndrome patients presented with AF and fast ventricular rates. Mean age of presentation was 38.5 ± 12.3 yrs. Twenty nine (72.5%) were male. Most common presenting features were palpitations, presyncope and syncope. Twenty eight (71.1%) patients were electrically cardioverted on presentation, of which two patients having narrow complex tachycardia, when given adenosine, developed AF and fast ventricular rates and had to be electrically cardioverted. Intravenous amiodarone converted AF to sinus rhythm in 11 (28.9%) patients. Right postero-septal pathway (33.3%) followed by coronary sinus epicardial pathway (22.9%) were the most commonly located pathways associated with AF. Five (12.2%) patients had multiple pathways. CS diverticulum was seen in 6 (14.7%) patients. Ablation was done during AF in 6 (14.7%) patients. All except one had immediate successful ablation. One patient had a recurrence of preexcitation on follow up and successfully ablated during redo procedure.

CONCLUSION

AF with WPW syndrome is not uncommon. AF is commonly associated with posteriorly located accessory pathways, CS diverticulum and multiple pathways. Radiofrequency ablation has good outcomes.

High incidence of atrial fibrillation after successful catheter ablation of atrioventricular nodal reentrant tachycardia: a 15.5-year follow-up

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common type of supraventricular tachycardia. Slow pathway (SP) ablation is the treatment of choice with a high acute success rate and a negligible periprocedural risk. However, long-term outcome data are scarce. The aim of this study was to assess long-term outcome and arrhythmia free survival after SP ablation. In this study, 534 consecutive patients with AVNRT, who underwent SP ablation between 1994 and 1999 were included. During a mean follow-up of 15.5 years, 101 (18.9%) patients died unrelated to the procedure or any arrhythmia. Data were collected by completing a questionnaire and/or contacting patients. Clinical information was obtained from 329 patients (61.6%) who constitute the final study cohort. During the electrophysiological study, sustained 1:1 slow AV nodal pathway conduction was eliminated in all patients. Recurrence of AVNRT was documented in 9 patients (2.7%), among those 7 patients underwent a successful repeat ablation procedure. New-onset atrial fibrillation (AF) was documented in 39 patients (11.9%) during follow-up. Pre-existing arterial hypertension (odds ratio 2.61, 95% CI 1.14–5.97, p = 0.023), age (odds ratio 1.05, 95% CI 1.02–1.09, p = 0.003) and the postinterventional AH interval (odds ratio 1.02, 95% CI 1.00–1.04, p = 0.038) predicted the occurrence of AF. The present long-term observational study after successful SP ablation of AVNRT confirms its clinical value reflected by low recurrence and complication rates. The unexpectedly high incidence of new-onset AF (11.9%) may impact long-term follow-up and requires further clinical attention.

Advanced interatrial block predicts recurrence of atrial fibrillation after accessory pathway ablation in patients with Wolff-Parkinson-White syndrome

BACKGROUND

Paroxysmal atrial fibrillation (AF) frequently occurs in patients with Wolff-Parkinson-White (WPW) syndrome. Although successful ablation of the accessory pathway (AP) eliminates paroxysmal AF in some patients, in other patients it can recur.

HYPOTHESIS

We investigated the clinical utility of advanced interatrial block (IAB) for predicting the risk of AF recurrence in patients with verified paroxysmal AF and WPW syndrome after successful AP ablation.

METHODS

This retrospective study included 103 patients (70 men, 33 women; mean age, 44 ± 16 years) with WPW syndrome who had paroxysmal AF. A resting 12-lead electrocardiogram was performed immediately after successful AP ablation to evaluate the presence of advanced IAB, which was defined as a P-wave duration of >120 ms and biphasic [±] morphology in the inferior leads.

RESULTS

During the mean follow-up period of 30.9 ± 20.0 months (range, 2-71 months), 16 patients (15.5%) developed AF recurrence. Patients with advanced IAB had significantly reduced event-free survival from AF (P < .001). Cox regression analysis with adjustment for the left atrial diameter and CHA₂ DS₂ -VASc score identified advanced IAB (hazard ratio, 9.18; 95% confidence interval [CI], 2.30-36.72; P = .002) and age > 50 years (hazard ratio, 12.64; 95% CI, 1.33-119.75; P = .027) as independent predictors of AF recurrence.

CONCLUSIONS

Advanced IAB was an independent predictor of AF recurrence after successful AP ablation in patients with WPW syndrome.

P-wave dispersion: What we know till now?

P-wave dispersion is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different-surface ECG leads. It has been known that increased P-wave duration and P-wave dispersion reflect prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses, which are well-known electrophysiologic characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation. Extensive clinical evaluation of P-wave dispersion has been performed in the assessment of the risk for atrial fibrillation in patients without apparent heart disease, in hypertensives, in patients with coronary artery disease, in patients undergoing coronary artery bypass surgery, in patients with congenital heart diseases, as well as in other groups of patients suffering from various cardiac or non-cardiac diseases. In this paper, we aimed to summarize the measurement methods, current use in different clinical situations, strengths and limitations of the of P-wave dispersion.

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.

Atrial conduction delay predicts atrial fibrillation in paroxysmal supraventricular tachycardia patients after radiofrequency catheter ablation

This study aimed to assess whether intra- and inter-atrial conduction delay could predict atrial fibrillation (AF) for paroxysmal supraventricular tachycardia (PSVT) patients after successful treatment by radiofrequency catheter ablation (RFCA). Echocardiography examination was performed on 524 consecutive PSVT patients (15 patients were excluded). Left atrial dimension, right atrial diameter and intra- and inter-atrial conduction delay were measured before ablation. Patients were divided into group A (n = 32): occurrence of AF after the ablation and group B (n = 477): remained in sinus rhythm during follow-up. Receiver operating characteristic (ROC) curve analysis was performed to estimate the predictive value of intra- and inter-atrial conduction delay. Both intra- and inter-atrial conduction delay were higher in group A than in group B (4.79 ± 0.30 msec vs. 4.56 ± 0.32 msec; 21.98 ± 1.32 msec vs. 20.01 ± 1.33; p < 0.05). Binary logistic regression analysis showed that intra- and inter-atrial conduction were significant influential factors for the occurrence of AF (odds ratio [OR] = 13.577, 95% confidence interval [CI], 3.469-48.914; OR = 2.569, 95% CI, 1.909-3.459, p < 0.05). The ROC cure analysis revealed that intra-atrial conduction delay ≥ 4.45 msec and inter-atrial conduction delay ≥ 20.65 were the most optimal cut-off value for predicting AF in PSVT patients after RFCA. In conclusion, this is the first study to show that the intra- and inter-atrial conduction delay could effectively predict AF in post-ablation PSVT patients.

Increased prevalence of atrial fibrillation in the endurance athlete: potential mechanisms and sport specificity

Atrial fibrillation is a common, often symptomatic, and concerning arrhythmia that can lead to heart failure, decreased athletic tolerance, and thromboembolic events; it has also been associated with increased mortality. Although atrial fibrillation is an uncommon condition in younger and otherwise healthy people, recent emerging evidence indicates that endurance athletes may be at particularly high risk of developing atrial fibrillation. We review the evidence that atrial fibrillation is associated with intense endurance athletics and we also explore the mechanisms by which this may occur. Finally, we consider some of the options that are available to treat athletes who develop atrial fibrillation.

Coexistence of Left-Sided Atrioventricular Accessory Pathways With a Common Inferior Pulmonary Vein Ostium

Background—

As the technique for radiofrequency catheter ablation for atrial fibrillation (AF) has progressed, so has our knowledge of both normal and abnormal anatomy of the left atrium and pulmonary veins (PV). We treated several AF patients with accessory conduction pathways (ACP) who were also found to have a common ostium of inferior PVs (CIPV), a relatively rare PV anomaly. No relation between ACP and PV anomalies has ever been reported, and the aim of our study was to study this association.

Methods and Results—

This study included 137 consecutive patients (104 men; mean age, 60±9 years) who underwent AF ablation for paroxysmal and persistent AF at our institution from March 2009 to August 2010. We analyzed coexisting supraventricular tachycardias and left atrium and PV morphology by multidetector row CT. Thirty-eight of 137 patients (27.7%) were found to have some PV anomaly, consisting of 13 with a common trunk of left PV, 19 with right additional PV, 3 with a common trunk of right PV, and 3 with CIPV. Thirty-one patients (22.6%) had supraventricular tachycardias. They were 26 cases of atrial flutter, 4 of Wolff-Parkinson-White syndrome, and 3 of atrioventricular nodal reentrant tachycardia. The prevalence of a coexisting ACP was significantly higher in patients with CIPV than in those without CIPV (3 of 3 [100%] versus 1 in 134 [0.7%]; P <0.0001). All ACPs with CIPV were located in the left side. The other supraventricular tachycardias were not associated with any PV anomalies.

Conclusions—

There is a possible association between CIPV and left-sided ACP in AF patients. This suggests that there is a likelihood of developmental association between them.

Atrial Fibrillation in the Wolff-Parkinson-White Syndrome

Since the advent of catheter ablation for atrial fibrillation (AF) aiming the pulmonary veins a few years ago, there has been an overwhelming interest and a dramatic increase in AF investigation. AF has a different dimension in the context of the Wolff-Parkinson-White (WPW) syndrome. Indeed, AF may be a nightmare in a young person that has an accessory pathway (AP) with fast anterograde conduction. It may be life-threatening if an extremely rapid ventricular response develops degenerating into ventricular fibrillation. Therefore, it is very important to know the mechanisms involved in the development of AF in the WPW syndrome. There are several possible mechanisms that may be involved in the development of AF in the WPW syndrome, namely, spontaneous degeneration of atrioventricular reciprocating tachycardia into AF, the electrophysiological properties of the AP, the effects of AP on atrial architecture, and intrinsic atrial muscle vulnerability. Focal activity, multiple reentrant wavelets, and macroreentry have all been implicated in AF, perhaps under the further influence of the autonomic nervous system. AF can also be initiated by ectopic beats originating from the pulmonary veins, and elsewhere. Several studies demonstrated a decrease incidence of AF after successful elimination of the AP, suggesting that the AP itself may play an important role in the initiation of AF. However, since AF still occurs in some patients with the WPW syndrome even after successful ablation of the AP, there should be other mechanisms responsible for the development of AF in the WPW syndrome. There is a clear evidence of an underlying atrial muscle disease in patients with the WPW syndrome. Atrial myocardial vulnerability has been studied performing an atrial endocardial catheter mapping during sinus rhythm, and analizing the recorded abnormal atrial electrograms. This review analizes the available data on this singular setting since AF has a reserved prognostic significance in patients with the WPW syndrome, and has an unusually high incidence in the absence of any clinical evidence of organic heart disease.

Electrophysiological characteristics of orthodromic reentrant tachycardia in patients with Wolf-Parkinson-White syndrome and atrial fibrillation

The aim of this study was to evaluate differences in the electrophysiological features of atrioventricular reentrant tachycardia (AVRT) in patients with Wolf-Parkinson-White syndrome (WPW) associated with or without atrial fibrillation (AF). We included 119 patients with WPW and orthodromic AVRT during electrophysiological study. The patients were divided into two groups; group I with documented episodes of AF (n=39, mean age 33.3+/-11.5 years), and group II without AF (n=80, mean age 35.3+/-13.8). We compared parameters of accessory pathway (AP), atrium and ventricle between two groups and found no significant difference. We next assessed the electrophysiological parameters of AVRT in both groups in terms of conduction times and atrioventricular (AV) activation relations. A significant negative correlation was found in group II between anterograde and retrograde conduction times measured as AV and VA intervals at the site of the earliest atrial activation (r=-0.43, P<0.0001), whereas no significant correlation was seen in group I (r=-0.29, P=0.1). Comparative analysis between two groups revealed significant difference in A-V/V-V index (P=0.05). These data suggest the presence of different electrophysiological properties of AP during AVRT in only few respects in patients with AF compared to those without it.

[Recurrence of atrial fibrillation after successful radiofrequency catheter ablation of accessory pathway in patients with Wolff-Parkinson-White syndrome]

INTRODUCTION

Paroxysmal atrial fibrillation (AF) occurs in 11.5-39% of the patients with Wolff-Parkinson-White (WPW) syndrome and frequently, but not always, disappears after successful accessory pathway (AP) ablation.

OBJECTIVE

To determine AF recurrence rate, time to AF recurrence and predictors of AF recurrence after radiofrequency (RF) catheter-ablation of AP in WPW-patients with AF.

METHODS

Data from 245 consecutive patients with WPW-syndrome who underwent RF catheter-ablation of AP were analysed. A total of 52 patients (43 men, mean age: 42.5 +/- 14.1 years) with preablation history of spontaneous AF were followed up after definitive AP ablation. At baseline, structural heart disease and comorbidities were diagnosed in 19.2% and 21.2% of the patients, respectively.

RESULTS

During the follow-up of 5.2-3.7 years, 3 patients (5.7%) died; one of these patients, previously known for recurrent AF, died from ischaemic stroke. Symptomatic recurrence of AF was detected in 9 of 52 patients (17.3%). In 66.7% of these patients, AF recurrence was identified in the first year following the procedure. Kaplan-Meier analysis demonstrated that freedom from recurrent AF after 3 months was 94.2%, after 1 year 87.5% and after 4 years 84.3%. Univariate analysis showed that older age (p = 0.023), presence of structural heart disease (p = 0.05) and dilated left atrium (p = 0.013) were significantly related to AF recurrence. However, using multivariate Cox regression, older age was the only independent predictor of AF recurrence (HR = 2.44 for every life decade; p = 0.006). Analysis of ROC curves showed that, after the age of 36, the risk of AF recurrence abruptly increased.

CONCLUSION

Symptomatic recurrence of AF was detected in 17% of WPW-patients after definite RF ablation of AP. The time-dependent occurrence of AF recurrences and age-dependent increase in the rate of AF recurrence were identified. Closer follow-up and/or extension of drug therapy in older patients, at least in the first year after the procedure, seem prudent.

Evaluation of atrial vulnerability immediately after radiofrequency catheter ablation of accessory pathway in patients with Wolff-Parkinson-White syndrome

PURPOSE

The intrinsic atrial vulnerability is proposed as one of the mechanisms of paroxysmal atrial fibrillation (PAF) in Wolff-Parkinson-White (WPW) syndrome. In this study, we examined the early changes in atrial refractoriness and intra- and inter-atrial conduction times after radiofrequency (RF) catheter ablation of accessory pathway (AP).

METHODS

Twenty-four consecutive patients with WPW syndrome and documented AV reciprocating tachycardia but without history of PAF (fourteen male, mean age 39 +/- 9.5 years) and 27 control subjects (six female, mean age 51.4 +/- 10.1 years) with AV nodal reentrant tachycardia (AVNRT) who underwent ablation of the slow AV nodal pathways were enrolled into the study. Regional atrial effective refractory periods (AERPs), AERP dispersion, and intra- and inter-atrial conduction times were obtained before and 30 min after ablation and were compared between two groups. In the study group, patients with and without inducible AF were also compared regarding these parameters.

RESULTS

In the study group, AERPs in higher right atrium and right posterolateral atrium were significantly increased, and AERP dispersion, intra-atrial, and inter-atrial conduction times were significantly decreased after ablation; AERP in distal coronary sinus was unchanged. In control group, no significant difference was observed in these parameters. Inducibility of AF was significantly reduced following ablation of AP in the study group (from seven to zero of 24 patients, p = 0.016). Comparison between patients with (n = 7) and without (n = 17) AF revealed that left atrium diameter was larger, AERPs in the right posterolateral atrium before and after ablation, and ERP of AP were shorter in AF group.

CONCLUSION

In WPW syndrome patients, RF catheter ablation of AP results in an 'immediate' decrease in atrial vulnerability. Since inducibility of AF becomes more difficult in this less vulnerable atrium, the AP itself may play an important role in the development of AF.

When should we recommend catheter ablation for patients with the Wolff-Parkinson-White syndrome?

PURPOSE OF REVIEW

Catheter ablation has been proven as very effective and safe therapy for patients with symptomatic Wolff-Parkinson-White (WPW) syndrome. Its application in asymptomatic individuals with WPW pattern remains controversial. This review will elaborate on the role of catheter ablation in symptomatic and asymptomatic patients with WPW pattern on ECG.

RECENT FINDINGS

Several recent prospective studies evaluated invasive risk stratification followed by prophylactic catheter ablation in asymptomatic patients with WPW pattern. Inducibility of arrhythmias in these patients during invasive electrophysiological study was shown to predict the development of future symptomatic arrhythmias. Although ablation of accessory pathways performed in 'inducible' patients decreased the incidence of subsequent symptomatic arrhythmias, the studies were not powered to detect a reduction in life-threatening arrhythmias.

SUMMARY

Radiofrequency catheter ablation remains the first-line therapy for patients with symptomatic WPW syndrome. Invasive electrophysiological study and possible ablation of accessory pathway may be offered to well informed asymptomatic individuals with WPW if they are willing to trade the very small risk of subsequent sudden death or incapacity for a small immediate procedural risk of serious complications or death. Asymptomatic patients may require invasive risk stratification and possible catheter ablation for important social or professional reasons.

Regular supraventricular tachycardias associated with idiopathic atrial fibrillation

The present study analyzed the recurrence rate of idiopathic atrial fibrillation (AF) after elimination by radiofrequency ablation of the substrate for a regular tachycardia. Forty consecutive patients with idiopathic AF and a history of regular palpitations or documented regular tachyarrhythmias were prospectively included. Regular tachyarrhythmias were induced in 82.5% of patients: atrial flutter (42.4% of the inducible arrhythmias), atrial tachycardia (24.2%), atrioventricular (AV) nodal reentry (18.2%), AV reentry through a concealed accessory pathway (9.1%), and AV nodal reentry associated with right atrial tachycardia (6.1%). Dual AV node physiology with single or dual AV node echoes was demonstrated in 6.1% of patients without inducible arrhythmias. During follow-up (92 +/- 11 months), AF recurred in 19.2% of patients after successful radiofrequency ablation and in 69.2% after unsuccessful or not performed procedures (p <0.05). Left atrial diameter did not change after successful ablation but increased significantly in the population without elimination of the substrate (initial diameter 37.5 +/- 2 mm, final diameter 46.4 +/- 3.2 mm; p <0.05). In conclusion, the systematic search for the substrate of regular tachyarrhythmias followed by their elimination by catheter ablation reduces the recurrence of idiopathic AF in patients with a history of regular palpitations or documented regular tachyarrhythmias.

Perception and documentation of arrhythmias after successful radiofrequency catheter ablation of accessory pathways

BACKGROUND

Some patients continue to have palpitations in spite of successful ablation of Wolff-Parkinson-White (WPW) syndrome. Recurrence of accessory pathways as well as unrelated arrhythmias may explain the symptoms.

METHODS

We followed 194 consecutive patients after successful radiofrequency catheter ablation of overt (147) or concealed (47) WPW syndrome. The mean duration of symptoms was 16 +/- 13 years. Atrial fibrillation was documented in 54 patients (24%) prior to ablation. 185 patients responded to a questionnaire 24 +/- 12 months after ablation.

RESULTS

The physical well-being was improved in 94%, unchanged in 5%, and deteriorated in 1%. However, 76 patients (39%) reported arrhythmia symptoms, in 40 patients causing pharmacological treatment (14 patients) and/or continued contact with their doctor. The underlying arrhythmias were orthodromic tachycardia (10), atrial fibrillation (12), premature beats (12), atrial flutter (1), and ventricular tachycardia (1), while in four patients no explanation was found. Minor symptoms in the other 36 patients were explained by premature beats in 29, while unexplained in 7. All patients with atrial fibrillation after ablation had atrial fibrillation before ablation. Ten relapses of WPW syndrome occurred: eight were known before the time of the questionnaire, two were confirmed at transesophageal atrial stimulation.

CONCLUSION

94% patients with a long history of tachyarrhythmias due to the WPW syndrome reported improved physical well-being after ablation, but palpitations were common during a 2-year follow-up period; 8% continued to use pharmacological antiarrhythmic treatment. Five percent had symptomatic relapses and in 6% atrial fibrillation episodes reoccurred, i.e., in half of those who had atrial fibrillation before ablation.

Prevalence of inducible paroxysmal supraventricular tachycardia during esophageal electrophysiologic study in patients with unexplained stroke

BACKGROUND

The relationships between stroke and atrial tachycardia or atrial fibrillation were previously reported. Electrophysiological study is one of the means, used to detect and evaluate these atrial tachyarrhythmias. But, some other arrhythmias as paroxysmal supraventricular tachycardia, can be induced during electrophysiologic study and their significance in stroke is unknown. The aim of the study was to assess the significance of inducible paroxysmal supraventricular tachycardia (PSVT) in stroke.

METHODS

One hundred thirty seven patients, aged 61+/-12 years had unexplained stroke (group I) and were compared to 60 subjects aged 45+/-18.5 years without stroke and history of tachycardia (group II); Holter monitoring (HM), echocardiogram and esophageal electrophysiologic study (EPS) in basal state and after isoproterenol were performed.

RESULTS

Heart disease was noted in 19 group I patients (14%) and 10 group II patients (17%). In group I, atrial fibrillation or tachycardia (AF-AT) was induced in 20 patients (15%) and PSVT was induced in 19 patients (14%) aged 66+/-12 years. In group II, AF/AT was induced in 3 patients (5%); no group II patient had induced PSVT. After 3+/-1 years, in group I, one of 98 patients without induced arrhythmias had new strokes and 2 had AF; 5 patients with induced AT/AF developed AF; 5 patients with induced PSVT had PSVT's, requiring ablation in 4 of them; 1 died from a new stroke; one had a second non-fatal stroke and 3 patients developed AF (16%). In group II, there were no events.

CONCLUSION

In 14% of patients with unexplained stroke, PSVT was inducible during esophageal electrophysiologic study. Further studies are warranted to assess the significance of this finding in patients with unexplained stroke.

Atrial vulnerability is a major mechanism of paroxysmal atrial fibrillation in patients with Wolff–Parkinson–White syndrome

Atrioventricular re-entrant tachycardia is the most common form of tachycardia in patients with Wolff-Parkinson-White (WPW) syndrome where one or more accessory pathways are present between atria and ventricles. Paroxysmal atrial fibrillation (PAF) is also a relatively common form of tachycardia in these patients. The mechanisms of PAF in patients with WPW syndrome are not completely understood. Previous studies have mainly focused on the role of accessory pathways in the development of PAF. However, up to 24% of patients still experience PAF after successful ablation of accessory pathways by surgical incision or radiofrequency catheter ablation techniques. We hypothesized that there are two primary mechanisms involved in the pathogenesis of PAF in patients with WPW syndrome. One is related to the accessory pathways that predispose the atria to fibrillation; the other is increased atrial vulnerability that is independent of the accessory pathways. Clarification of these mechanisms is critical in developing more effective means for the prevention or treatment of PAF in patients with WPW syndrome.

Recurrence of symptomatic atrial fibrillation after successful catheter ablation of atrioventricular accessory pathways: a multivariate regression analysis

The primary aim of this study is to investigate the factors related to the recurrence of atrial fibrillation (AF) after a successful ablation of atrioventricular accessory pathway. Thirty-seven patients with spontaneous AF (study group) were selected from 401 consecutive patients who underwent radiofrequency catheter ablation of atrioventricular accessory pathway. A multivariate regression analysis was used in order to evaluate the relationships between AF recurrence and patients' age, sex, atrial size, left ventricular function, location of accessory pathways, heart rate during atrioventricular re-entrant tachycardia and atrial vulnerability (induction of sustained AF) after a successful ablation. Atrioventricular accessory pathway was abolished in 36 of the study group patients and 351 of the control group patients. During the follow-up of 36 +/- 11 months, four patients (11.1%) from the study group experienced sustained AF. Multivariate regression analysis showed that, in patients with pre-ablation AF, older age and post-ablation atrial vulnerability were the only independent predictive factors for AF recurrence. We concluded that radiofrequency catheter ablation of atrioventricular accessory pathway greatly reduces the risk of AF in patients who had a history of symptomatic AF. Older patients and patients with inducible AF after accessory pathway ablation are at an increased risk of AF recurrence. These patients should be closely monitored after successful ablation of atrioventricular accessory pathways.

Increased P wave dispersion after the radiofrequency catheter ablation in overt pre-excitation patients: the role of atrial vulnerability

The pathogenesis of paroxysmal atrial fibrillation (PAF) in patients with overt pre-excitation and effect of elimination of accessory pathways on the appearance of AF are still controversial. We demonstrated the increased P max and P wave dispersion (PWD) reflecting more inhomogeneous and prolonged atrial conduction in patients with Wolff-Parkinson-White (WPW) syndrome and PAF attacks. One-hundred and fifty-one patients who underwent radiofrequency (RF) catheter ablation due to paroxysmal tachycardia medicated by accessory pathway were enrolled in this study. The patients were classified into two groups according to the presence of previous PAF attacks. We compared the clinical characteristics, echocardiograhic findings, P max and PWD values measured after normalization of PR intervals and disappearance of pre-excitation after ablation in overt pre-excitation patients. Although the differences in age, left atrial diameter and left ventricular ejection fraction (LVEF) were not significant in both groups, P maximum (130.0+/-8.4 vs. 122.3+/-8.7 ms, p=0.002) and P wave dispersion values measured after ablation (50.3+/-7.2 vs. 35.7+/-6.1 ms, p=0.001) were significantly higher in patients with previous PAF attacks. Accessory pathway (AP) antegrade and retrograde effective refractory period (ERP) values were shorter (276+/-27.3 vs. 321.0+/-48.7, p=0.001; 263.4+/-41.3 vs. 299.7+/-38.2, p=0.002, respectively) in patients with PAF attack when compared to those without PAF attacks. Higher P wave dispersion values in patients with previous PAF attacks suggest the important role of inhomogenous and discontinuous propagation of sinus impulses. Therefore, we concluded that not only the accessory pathway but also inhomogenous propagation of sinus impulses may play an important role in occurrence of AF in patients with pre-excitation.

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.

Atrial electrophysiological properties evaluated by right and left atrial pacing in patients with or without atrial fibrillation

Coronary sinus (CS) pacing has been shown to prevent induction of atrial fibrillation (AF) by suppression of the propensity of atrial premature beats at high right atrium (HRA) to induce local conduction delay at the posterior triangle of Koch. However, other mechanisms of CS pacing in preventing induction of AF have not been explored. This study investigated whether a differential conduction delay exists between the HRA and distal CS pacing in patients with paroxysmal AF but not in patients without AF. Nine patients with atrioventricular reentrant tachycardia utilizing a left accessory pathway undergoing catheter ablation were included in this study. Group 1 consisted of 5 patients with clinically documented paroxysmal AF and group 2 4 patients without a history of AF. The effective refractory periods (ERPs) of HRA, distal CS, and four different left atrial sites were determined. The interatrial conduction time and conduction delay between the HRA and distal CS during HRA or distal CS pacing were measured. The interatrial conduction delay (ICD) from the HRA to the distal CS during HRA pacing was significantly longer than that from the distal CS to the HRA during distal CS pacing in patients of group 1. However, the ICD from the HRA to the distal CS during HRA pacing was not significantly longer than that from the distal CS to the HRA during distal CS pacing in group 2 patients. A differential conduction delay between the HRA and the distal CS pacing is present in this specific population of patients with paroxysmal AF but not in patients without AF. The shorter conduction delay during DCS pacing may contribute to the prevention of induction of AF.

Evaluation and management of atrial fibrillation

Atrial fibrillation is a common cardiac arrhythmia with significant sequela. The goals of treating atrial fibrillation are rate control, prevention of thromboembolism, and maintenance of sinus rhythm. The epidemiology and pathophysiology of atrial fibrillation is reviewed, as well as strategies and recommendations for achieving therapeutic goals. The authors also review investigational therapeutic options using nonpharmacologic modalities.

Atrioventricular nodal tachycardia occurring during atrial fibrillation

We describe the case of a 32-year-old woman with palpitations and atrial fibrillation (AF) as the only documented arrhythmia. The patient underwent electrophysiologic study and was found to have inducible AV nodal reentrant tachycardia (AVNRT). During a prolonged episode of AVNRT, AF developed in both atria, but AVNRT persisted. Dissociation of the atria during AVNRT is evidence that the atrium is not necessary in AVNRT. This case also illustrates the utility of an electrophysiologic study in locating a potentially curable arrhythmia as the primary cause of AF in young patients.