Accessory Atrioventricular Pathway Research Articles

Radiofrequency Catheter Ablation of Left-sided Accessory Atrioventricular Pathways at Atrial Insertion Sites

Background: This study assessed the efficacy and safety of techniques used to ablate left-sided accessory atrioventricular pathways at atrial insertion sites by retrograde aortic approach. Radiofrequency catheter ablation of left-sided accessory pathways by way of retrograde aortic approach can be highly successful. Methods: This study were done in the department of Cardiology, National Institute of Cardiovascular Diseases (NICVD), Dhaka from June 2009 and March 2010, a total 30 patients with recurrent SVT who has left sided accessory atrioventricular pathways found after electrophysiological study, underwent attempted radiofrequency catheter ablation of one or more accessory atrioventricular pathways by retrograde aortic approach. The ablation catheter was inserted into the femoral artery and passed retrogradely across the aortic valve .Once an optimal target site has been identified, radiofrequency energy at a pre-selected temperature of 55 - 60 0 C and power output set at 50 watts was delivered through the ablation catheter. Loss of preexcitation or interruption of the tachycardia within 5 seconds of RF application was considered effective and RF current was continued in this location 30 to 60 seconds. Ablation success was defined at completion of procedure as acutely successful or unsuccessful on the basis of successful elimination of all ablation targets. Results: During EP study it was found that 9 patients had concealed accessory pathways and 21 had manifest pre-excitation. WPW left-lateral pathway was present in 10 (33.3%), concealed left lateral in 08 (26.7%), WPW left posterior in 11 (36.7%), concealed left posterior in 1 (3.3%). Out of 30 accessory pathways, 24 were successfully interrupted with radiofrequency catheter ablation with a primary success rate of 80 %. The ratio of atrial/ ventricular electrogram in successful sites was 0.83 ±0.27 (0.53-1.46). There were no major complications with retrograde aortic approach. Six failed patients were ablated via transseptal method. Conclusion: The retrograde atrial insertion approach to left-sided accessory pathway ablation is very safe and high effective, especially suitable for the failed patients by using retrograde ventricular insertion ablation procedure and by using single-catheter ablation of accessory pathway. DOI: http://dx.doi.org/10.3329/uhj.v9i1.19507 University Heart Journal Vol. 9, No. 1, January 2013; 18-24

A case series of patients with poorly-tolerated arrhythmias related to a preexcitation syndrome and presenting with atypical ECG

The aim of study was to report different and unusual patterns of preexcitation syndrome (PS) noted in patients referred for studied for poorly-tolerated arrhythmias and their frequency. Electrophysiologic study (EPS) is an easy means to identify a patient with PS at risk of serious events. However the main basis for this diagnosis is the ECG which associates short PR interval and widening of QRS complex with a delta wave. MethodsECGs of 861 patients in whom PS related to an atrioventricular accessory pathway (AP) was identified at electrophysiological study (EPS), were studied. ResultsThe most frequent unusual presentation (9.6%) was the PS presenting with a normal or near normal ECG, noted preferentially for left lateral AP and rarely for posteroseptal or right lateral location. More exceptional (0.1%) was the presence of a long PR interval, which did not exclude a rapid conduction over AP. The association of a complete AV block with symptomatic tachycardias was exceptional (0.3%) and was shown related to a rapid conduction over AP after isoproterenol. Most of the presented patients were at high-risk at EPS. ConclusionThe diagnosis of PS is not always evident and symptoms should draw attention to minor abnormalities and lead to enlarge indications of EPS, only means to confirm or not PS.

A case of manifest Wolff-Parkinson-White syndrome with atrioventricular accessory pathway apparently in an oblique course due to loose electrical connections between coronary sinus musculature and left atrium

A case of manifest Wolff-Parkinson-White syndrome with atrioventricular accessory pathway apparently in an oblique course due to loose electrical connections between coronary sinus musculature and left atrium

Radiofrequency ablation of a left lateral atrioventricular accessory pathway in a 13-year-old boy with a criss-cross heart guided by nonfluoroscopic imaging

We present the first description of successful radiofrequency (RF) ablation of a bidirectional atrioventricular accessory pathway (AP) guided by nonfluoroscopic mapping with use of three-dimensional magnetic resonance imaging integrated into the Nav-X system (MRI/Nav-X fusion) in a 13-year-old boy with remote surgical palliation for cyanotic criss-cross heart with atrioventricular discordance, double-outlet right ventricle, and a large ventricular septal defect. Due to complex anatomy, a unique finding was that the eliminated left lateral AP electrically connected the left atrium to the antero-superior morphologic right ventricle prior to ablation.

Spanish Catheter Ablation Registry. 12th Official Report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2012)

Introduction and objectivesThis article presents the findings of the 2012 Spanish Catheter Ablation Registry. MethodsData were collected in 2 ways: retrospectively using a standardized questionnaire, and prospectively using a central database. Each participating center selected its own preferred method of data collection. ResultsSeventy-four Spanish centers voluntarily contributed data to the survey. A total of 11 042 ablation procedures were analyzed, averaging 149 (103) per center. The 3 main conditions treated were atrioventricular nodal reentrant tachycardia (n=2842; 25.7%), cavotricuspid isthmus (n=2485; 23%), and accessory pathways (n=1999; 18%). Atrial fibrillation was the fourth most common substrate treated (n=1852; 17%), representing a slight increase. The number of ventricular arrhythmia ablation procedures was similar to that of 2011, but there was a decrease in procedures for ventricular tachycardia associated with postinfarction scarring. The overall success rate was 94.9%, major complications occurred in 1.9%, and the overall mortality rate was 0.04%. ConclusionsData from the 2012 registry show that the number of ablations performed continued to increase. Overall, they also show a high success rate and a low number of complications. Ablation of complex substrates continued to increase, particularly in the case of atrial fibrillation.

Registro Español de Ablación con Catéter. XII Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2012)

Introduction and objectivesThis article presents the findings of the 2012 Spanish Catheter Ablation Registry. MethodsData were collected in 2 ways: retrospectively using a standardized questionnaire, and prospectively using a central database. Each participating center selected its own preferred method of data collection. ResultsSeventy-four Spanish centers voluntarily contributed data to the survey. A total of 11 042 ablation procedures were analyzed, averaging 149 (103) per center. The 3 main conditions treated were atrioventricular nodal reentrant tachycardia (n=2842; 25.7%), cavotricuspid isthmus (n=2485; 23%), and accessory pathways (n=1999; 18%). Atrial fibrillation was the fourth most common substrate treated (n=1852; 17%), representing a slight increase. The number of ventricular arrhythmia ablation procedures was similar to that of 2011, but there was a decrease in procedures for ventricular tachycardia associated with postinfarction scarring. The overall success rate was 94.9%, major complications occurred in 1.9%, and the overall mortality rate was 0.04%. ConclusionsData from the 2012 registry show that the number of ablations performed continued to increase. Overall, they also show a high success rate and a low number of complications. Ablation of complex substrates continued to increase, particularly in the case of atrial fibrillation.Full English text available from:www.revespcardiol.org/en

Radiofrequency Catheter Ablation of Left-sided Accessory Atrioventricular Pathways at Atrial Insertion Sites.

Background: This study assessed the efficacy and safety of techniques used to ablate left-sided accessory atrioventricular pathways at atrial insertion sites by retrograde aortic approach. Radiofrequency catheter ablation of left-sided accessory pathways by way of retrograde aortic approach can be highly successful. Methods: This study were done in the department of Cardiology, National Institute of Cardiovascular Diseases (NICVD), Dhaka from June 2009 and March 2010, a total 30 patients with recurrent SVT who has left sided accessory atrioventricular pathways found after electrophysiological study, underwent attempted radiofrequency catheter ablation of one or more accessory atrioventricular pathways by retrograde aortic approach. The ablation catheter was inserted into the femoral artery and passed retrogradely across the aortic valve .Once an optimal target site has been identified, radiofrequency energy at a pre-selected temperature of 55 - 60 0 C and power output set at 50 watts was delivered through the ablation catheter. Loss of preexcitation or interruption of the tachycardia within 5 seconds of RF application was considered effective and RF current was continued in this location 30 to 60 seconds. Ablation success was defined at completion of procedure as acutely successful or unsuccessful on the basis of successful elimination of all ablation targets. Results: During EP study it was found that 9 patients had concealed accessory pathways and 21 had manifest pre-excitation. WPW left-lateral pathway was present in 10 (33.3%), concealed left lateral in 08 (26.7%) ,WPW left posterior in 11 (36.7%), concealed left posterior in 1 (3.3%). Out of 30 accessory pathways, 24 were successfully interrupted with radiofrequency catheter ablation with a primary success rate of 80 %. The ratio of atrial/ ventricular electrogram in successful sites was 0.83 ±0.27 (0.53-1.46). There were no major complications with retrograde aortic approach. Six failed patients were ablated via transseptal method. Conclusion: The retrograde atrial insertion approach to left-sided accessory pathway ablation is very safe and high effective, especially suitable for the failed patients by using retrograde ventricular insertion ablation procedure and by using single-catheter ablation of accessory pathway. DOI: http://dx.doi.org/10.3329/uhj.v8i2.16081 University Heart Journal Vol. 8, No. 2, July 2012

Identification of a Novel De Novo Mutation Associated with PRKAG2 Cardiac Syndrome and Early Onset of Heart Failure

IntroductionThe major structure elements of the AMP-activated protein kinase (AMPK) are α, β, and γ sunbunits. Mutations in γ2 subunit (PRKAG2) have been associated with a cardiac syndrome including inherited ventricular preexcitation, conduction disorder and hypertrophy mimicking hypertrophic cardiomyopathy. The aim of the present study was to identify PRKAG2 syndrome among patients presenting with left ventricular hypertrophy (LVH).Methods and ResultsNineteen unrelated subjects with unexplained LVH were clinically and genetically evaluated. Among 4 patients with bradycardia, manifestations of preexcitation were only found in a 19 year old male who also developed congestive heart failure 3 years later. Electrophysiological study of this case identified the coexistence of an AV accessory pathway and AV conduction defect. Histological analysis of his ventricular tissue isolated by biopsy confirmed excessive glycogen accumulation, prominent myofibrillar disarray and interstitial fibrosis. Direct sequencing of his DNA revealed a heterozygous mutation in PRKAG2 consisting of an A-to-G transition at nucleotide 1453 (c.1453A>G), predicting a substitution of a glutamic acid for lysine at highly-conserved residue 485 (p.Lys485Glu, K485E), which was absent in his unaffected family members and in 215 healthy controls. To assess the role of K485 in the structure and function of the protein, computational modeling calculations and conservation analyses were performed. Electrostatic calculations indicate that K485 forms a salt bridge with the conserved D248 residue in the AMPK β subunit, which is critical for proper regulation of the enzyme, and the K485E mutant disrupts the connection.ConclusionsOur study identifies a novel de novo PRKAG2 mutation in a young, in which progression of the disease warrants close medical attention. It also underlines the importance of molecular screening of PRKAG2 gene in patients with unexplained LVH, ventricular preexcitation, conduction defect, and/or early onset of heart failure.

臨床 Wolff-Parkinson-White症候群における副伝導路高周波カテーテルアブレーション

臨床 Wolff-Parkinson-White症候群における副伝導路高周波カテーテルアブレーション

Management of Patients With Atrial Fibrillation (Compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS Recommendations)

This document is a compilation of the current American College of Cardiology Foundation/American Heart Association (ACCF/AHA) practice guideline recommendations for atrial fibrillation (AF) from the “ACC/AHA/ESC 2006 Guidelines for the Management of Patients With Atrial Fibrillation),”* the “2011 ACCF/AHA/HRS Focused Update on the Management of Patients With Atrial Fibrillation (Updating the 2006 Guideline)”† and the “2011 ACCF/AHA/HRS Focused Update on the Management of Patients With Atrial Fibrillation (Update on Dabigatran).”‡ Updated and new recommendations from 2011 are noted and outdated recommendations have been removed. No new evidence was reviewed, and no recommendations included herein are original to this document. The ACCF/AHA Task Force on Practice Guidelines chooses to republish the recommendations in this format to provide the complete set of practice guideline recommendations in a single resource. ### 1.1. Pharmacological and Nonpharmacological Therapeutic Options #### 1.1.1. Rate Control During AF Class I 1. Measurement of the heart rate at rest and control of the rate using …

ASSA13-02-11 Single-Centre Results of Gender and Age Differences of Paroxysmal Supraventricular Tachycardia

ObjectiveTo study the gender and age differences of paroxysmal supraventricular tachycardia.Methods1578 patients with consciously palpitations due to paroxysmal supraventricular tachycardia (PSVT) tachycardia were involved in this study. PSVT was confirmed...

302: Familial atrioventricular node reentrant tachycardias

Familial Wolff-Parkinson-White (WPW) syndrome and gene (PRKAG2) was reported. Rare case reports suggest that genetic factors may play a role in the formation of accessory atrioventricular pathways (AP) and dual AV nodal pathways. In this last case, nothing is known, probably because atrioventricular node re-entrant tachycardia (AVNRT) is associated with a good prognosis. The purpose of study was to look for familial forms of AVNRT. 792 patients with a preexcitation syndrome, 251 patients with a normal ECG but with atrioventricular re-entrant tachycardia (AVRT) using a concealed AP and 969 patients with AVNRT were referred in our department. Electrophysiological study (EPS) was performed in all subjects. The familial forms in these groups have been sought. Only patients with documented and/or induced supraventricular tachycardia were retained as having tachycardia. Among patients with a preexcitation syndrome, we did not find familial form of preexcitation syndrome. Sister of a young patient who had presented a WPW-related ventricular fibrillation complained of tachycardia, but AVNRT was identified at electrophysiological study (EPS). Two other patients had a family history of unexplained sudden death, but no ECG was recorded before death in these patients. Among patients with AVRT and normal ECG, one familial form was noted (father and daughter) (0.4%). Among patients with AVNRT, 7 families were identified (0.7%): mother and son (n=4), mother and daughter (n=1), brother and sister (n=1), father and daughter (n=1). The frequency of familial AVNRT was significantly higher than in patients with a preexcitation syndrome (p <0.025). The frequency of familial AVNRT was probably underestimated because frequently patients reported a familial history of tachycardia but the nature of the tachycardia could not be proven. A genetic origin of some AVNRT exists in some families. Its frequency is approximately 0.7% in our population. Although patients with AVNRT are not at risk of life-threatening arrhythmia, the history of tachycardia in family may lead to look for the same tachycardia. The frequency is higher than in preexcitation syndrome.

Catheter Ablation of an Unusual Decremental Accessory Pathway in the Left Coronary Cusp of the Aortic Valve Mimicking Outflow Tract Ventricular Tachycardia

The anatomic location of atrioventricular (AV) bypass tracts (or accessory pathways) is variable, but these generally traverse the tricuspid or mitral annulus and insert into the atrium and ventricle near the AV ring. There is only 1 case report of an accessory pathway ablated in the left coronary cusp (LCC),1 and this pathway had bidirectional conduction, was not decremental, and was associated with an orthodromic tachycardia. We report here the first case of an antegrade slowly conducting, decremental, accessory pathway that was also successfully ablated in the aortic LCC. This pathway generated antidromic tachycardia having a QRS morphology mimicking those seen in outflow tract ventricular tachycardia. A 42-year-old woman was evaluated for palpitations and presyncope for 2 years. These were commonly associated with shortness of breath and chest heaviness that would resolve spontaneously. Her baseline ECG was normal without ventricular preexcitation. Echocardiogram, coronary angiogram, and thyroid function were also unremarkable. On her third presentation to a hospital, a broad complex tachycardia was captured (representative 12-lead ECG shown in Figure 1). The cycle length was 480 ms, the QRS duration was 150 ms, and a left bundle branch morphology with a right inferior axis was noted. She was referred for ablation of suspected ventricular outflow tract tachycardia. Consent was obtained for mapping and ablation of this tachycardia. During placement of catheters, a spontaneous initiation of tachycardia occurred, which was noted to have 1:1 AV association. A quadripolar catheter was placed at the right ventricular apex and His bundle, with a decapolar catheter in the coronary sinus. During ventricular pacing, retrograde conduction occurred with a long ventriculoatrial interval. Tachycardia was readily initiated with ventricular premature beats showing retrograde decremental conduction (Figure 2). An antegradely conducting accessory pathway was noted during atrial pacing maneuvers. During delivery of premature atrial stimulations, shortening of …

Surgical ablation of atrial fibrillation after the PRAGUE-12 study: more questions than answers

This editorial refers to ‘Comparison of cardiac surgery with left atrial surgical ablation vs. cardiac surgery without atrial ablation in patients with coronary and/or valvular heart disease plus atrial fibrillation: final results of the PRAGUE-12 randomized multicentre study’, by P. Budera et al. , doi:10.1093/eurheartj/ehs290 No doubt surgical research has paved the way to curative treatment of cardiac arrhythmias. Long before the idea of catheter ablation was born, accessory atrioventricular pathways were interrupted by surgical knives, ventricular tachycardia was successfully treated by endocardial resection or scar circumcision, and even the first successful approaches to cure atrioventricular nodal re-entrant tachycardia were done in the surgical operating theatre. However, for these types of arrhythmias, surgical procedures are nowadays performed very rarely, mainly because of the tremendous success of catheter ablation. In atrial fibrillation (AF), current interventional treatment concepts and strategies would have been impossible without the milestone work of cardiac surgeons. The most important contribution came from James Cox and colleagues who established the Maze operation, the first curative treatment option for AF patients.1 In an attempt to replicate the Maze procedure with percutaneous catheters, John Schwarz initiated the development of catheter ablation procedures for AF in the early 1990s. Subsequently, and step by step, techniques and technologies were improved, and today catheter ablation is established as a leading treatment strategy for symptomatic patients with AF. In contrast, today stand-alone surgical ablation of AF does not play such a significant role. As indicated in a recent survey, failed catheter ablation currently is the most frequent indication for stand-alone surgical ablation.2 When compared with catheter ablation, surgical procedures are more invasive, more complex and complicated, and also more expensive. However, many patients with an indication for cardiac surgery because of coronary artery disease or valvular heart disease have or even suffer from …

Approach to the Difficult Septal Atrioventricular Accessory Pathway

Ablation of accessory tracts in the posteroseptal region can be challenging, as illustrated by these 2 cases. Familiarity of the anatomy of this region and recognition of the ECG patterns can help identify the AP origin and potentially improve success rates of ablation. The isoelectric initial preexcited QRS complex with rSR’ pattern in lead V1 of the surface ECG but not the relatively earlier local ventricular activation at PSMA region may indicate a left-sided ablation approach for these APs.

Pacemap of delta wave for successful ablation of traumatized atrioventricular accessory pathway

547-5271/$ -see front matter © 2012 Heart Rhythm Society. All rights reserved oss of AP conduction, but it appears that the vast majority of raumatized tissues recover (resumption of conduction) over a eriod ranging from several minutes to months. The ability to elocate the AP in order to complete the ablation procedure is onfounded by the time it takes to recover conduction. If onduction does not resume after mechanical trauma, radiofreuency (RF) ablation at the presumed AP location site may be ssociated with a poor ablation outcome or may lead to iscontinuation of the procedure. Rarely, persisting AP potenials may be used as a guide to ablation. We report a patient who underwent successful ablation of a right lateral AP by using pacemapping of the delta wave from the tricuspid annulus (TA) after mechanical trauma had eliminated conduction.

Two-dimensional speckle-tracking echocardiography for atrioventricular accessory pathways persistent ventricular pre-excitation despite successful radiofrequency ablation

The present study was undertaken to investigate the concordance between longitudinal two-dimensional (2D)-speckle-tracking data and endocardial mapping for localizing atrioventricular accessory pathways (AP), and whether longitudinal 2D-speckle-tracking imaging accurately identifies the contractile abnormalities associated with AP and the effect of radiofrequency ablation. Echocardiograms were repeated twice in 40 patients with Wolff-Parkinson-White (WPW) syndrome (before and early after ablation) and in 40 healthy controls to obtain longitudinal 2D strain and strain rate data. The site of ablation was considered as the gold standard for the AP localization. While control patients had a homogeneous strain pattern, all but two patients with WPW had an abnormal deformation pattern with three peaks in one or two basal contiguous segments: an early peak concomitantly with the delta wave followed by a systolic and a post-sytolic one. The rapid increase in LV longitudinal deformation within the basal pre-excited zone resulted in a pre-systolic peak strain rate at the beginning of the delta wave by SR imaging that was not found in controls. The early basal contraction spread towards the mid-ventricle before merging with the normal activated segments in 15 patients (39%). Contractile abnormalities were no more than one adjacent segment different compared with the AP ablation site in all these 38 patients. Regional strain was impaired in the pre-excited areas especially in AP localized in the interventricular septum. The abnormal deformation pattern persisted in 16 (42%) patients despite successful radiofrequency ablation. However, the difference in the regional strain between WPW patients and controls did not remain after ablation. Longitudinal 2D-speckle-tracking data accurately match with endocardial mapping findings for localizing AP. Longitudinal 2D-speckle-tracking imaging accurately identifies AP-associated contractile abnormalities. Longitudinal 2D-speckle-tracking identifies persistence of local ventricular pre-excitation immediately after successful ablation.

Postablation-acquired short atrioventricular Mahaim-type fibers: Observations on their clinical, electrocardiographic, and electrophysiologic profile

The electrophysiologic characteristics of decrementally conducting accessory pathways (APs) are well described; however, little is known about decrementally conducting APs caused by the radiofrequency ablation of a rapidly conducting AP. To report the clinical, electrocardiographic, and electrophysiologic characteristics of 6 patients who developed a decremental AP after an attempt at ablation. We compared the clinical and electrophysiologic characteristics of 295 consecutive patients with the Wolff-Parkinson-White syndrome who underwent radiofrequency ablation of 311 manifest APs (group A) with those of 6 patients with the Wolff-Parkinson-White syndrome in whom a decrementally conducting AP was detected after an attempt at ablation. The AP ablation site in group B patients was at the coronary sinus ostium region in 3 patients, middle cardiac vein in 2 patients, and left posteroseptal region in 1 patient. Sixty-two bypass tracts in group A patients and all 6 in group B patients were ablated at these locations, while 249 bypass tracts in group A patients and none in group B patients were ablated elsewhere (P = .0001). Five of the 6 patients (83%) with acquired Mahaim physiology had an AP located in the venous system. The odds for developing an acquired decremental antegrade atrioventricular AP when it was located inside the venous system were 1 in 6. All group B decremental APs were sensitive to adenosine, but none in 85 group A patients (P <.0001). The risk for developing decremental conduction after the ablation of a rapidly conducting AP is greater for APs inside the coronary venous system. Acquired decremental antegrade atrioventricular APs are electrophysiologically similar to de novo ones. They are capable of being part of an arrhythmia circuit and, therefore, should be targeted for ablation.

Immediate and long-term eff icacy and safety of catheter ablation of right anteroseptal atrio-ventricular accessory pathways

This study investigated long-term outcome of catheter ablation of right anteroseptal atrio-ventricular (AV) accessory pathways (AP) located close to the His bundle. MethodsBetween April 2003 and June 2011, 26 patients (6 females, age 35±13 years) underwent catheter ablation of right anteroseptal AP. These APs represented 10% of all 248 APs ablated within the given reference period. Elimination of AP conduction in both directions and preservation of normal AV conduction were the ablation procedure endpoints. ResultsFirst ablation was effective in 18 (69%) patients. After repeat ablation, AP was permanently eliminated in 22 (85%) patients (one, two, and three ablation procedures in 16, 5, and 1 patient, respectively). Ablation failed in 4 patients (1 procedure in 3 patients, 2 procedures in 1 patient). During 56±27 (4–102) month follow-up period since the last ablation, no late AP conduction recovery was found, and no late advanced AV block occurred. Post-ablation AV node Wenckebach point was present at the pacing rate of 176±26 (130–230) beats per minute. Of the two engaged operators, more experienced operator successfully accomplished first, second, and third ablation procedure in 14/16 (88%), 5/5 (100%), and 1/1 (100%) patients, respectively, the latter operator attained successful ablation in 4/10 (40%) and 1/2 (50%) patients at the first and second ablation procedures, respectively. ConclusionAblation of right anteroseptal AP close to the His bundle is feasible and safe. Late advanced AV block was not observed. Individual operator's experience influenced ablation efficacy.

P17 Profile of rheumatoid arthritis at first visit to a tertiary rheumatology centre

Non-documented palpitations, or phantom tachycardias, are palpitations deemed to be of unknown origin after evaluation with conventional diagnostic tools, such as 12-lead electrocardiogram and Holter recordings. Our aim was to determine the diagnostic value of an electrophysiologic study (EPS) and its role in the management of patients presenting with non-documented palpitations.We performed EPS in 78 consecutive patients with repeatable, poorly tolerated symptoms of paroxysmal, non-documented tachycardia, the absence of structural heart disease and at least one 24-h Holter recording. The duration and frequency of palpitations was registered in each patient.Long-lasting palpitations (>1 hour) were present in 15.4% of patients. Half of patients reported symptoms less often than once per week. Only 13/78 patients (16.6%) had normal EPS findings, while dual pathways at the AV node ± echo beats were identified in another 13 patients without inducible tachycardia. At least one tachycardia event was induced in 52 patients (66.6%). AVNRT was provoked in 32 patients (41.2%). Ablation was performed in 14/52 patients with inducible tachycardia (26.9%). Slow pathway ablation was also performed in three patients with dual AV pathways and atrial echo-beats but without provoked tachycardia. Follow-up data were available in 52 patients, and 84.6% had fewer or no clinical recurrences.EPS is safe and of enhanced diagnostic value in patients with unexplained palpitations because only 1/6 had negative results. EPS also provided an explanation about the mechanism of arrhythmia and successfully guided the management of these patients, as well as enhanced improvement in the quality of life.