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Patients with the Wolff-Parkinson-White syndrome may experience benign and malignant arrhythmias, the most common being atrioventricular reentrant tachycardias. This arrhythmia may degenerate into atrial fibrillation, which can be conducted over an accessory pathway capable of exceptionally fast conduction to the ventricles and degenerate into ventricular fibrillation, leading to sudden cardiac death. These life-threatening events generally affect symptomatic patients in their third or fourth decade. Although rare, ventricular fibrillation may be the first clinical manifestation in subjects who are asymptomatic or unaware of their conditions. Electrophysiologic study may be useful to identify subjects at high risk of sudden cardiac death.

Ablation of ganglionated plexuses (GPs) is a relatively new technique in patients with vasovagal syncope. Due to individual variation of GP settlement, reproducible GP detection methods are needed to during electrophysiologic study. In the present case, fractionation mapping software of Ensite system was tested to detect localization of GPs and first compared with previously validated fractionated electrograms based strategy.

Background To investigate the relationship between the location of accessory pathways, electrophysiologic characteristics, and ablation success in Wolfe-Parkinson-White (WPW) syndrome. Methods Electrophysiologic study was performed in 178 patients for a pre-excitation syndrome. Accessory pathway location, anterograde or retrograde conduction, ablation success, and recurrence rate were evaluated. Results Among 178 patients with WPW syndrome, the most frequent location of the accessory pathway was left lateral (39.3%) which had high ablation success rate (97%) and low recurrence rate (1%). A meaningful relationship exists between accessory pathway location and electrophysiologic characteristics. Ablation success rate was 89.7% and was statistically related to accessory pathway location. Recurrent occurred in 2.9% of our patients and was more frequent in right free wall and PJRT. Conclusions The location of accessory pathways has a great impact on conductivity, ablation success, and recurrence rate in WPW syndrome.

Introducao O desenvolvimento de dor precordial associada ao bloqueio de ramo esquerdo (BRE) intermitente na ausencia de doenca arterial coronariana tem sido descrito na literatura como sindrome do bloqueio de ramo esquerdo doloroso. O mecanismo responsavel pela dor precordial e desconhecido, mas a principal hipotese atualmente esta relacionada a dissincronia cardiaca aguda. Nessa sindrome, o BRE ocorre quando a duracao do ciclo e igual ou inferior ao periodo refratario do ramo esquerdo, principalmente durante o esforco fisico. A dor toracica [...]

Background The value of eletrophisiologic study (EPS) with programmed ventricular stimulation for risk stratification in patients with Brugada Syndrome (BS) remains controversial. Purpose The aim of this study is to determine the clinical and electrocardiographic predictors of positive EPS and to evaluate whether the induction of malignant ventricular dysrhythmias in the EPS is a predictor of events Methods A retrospective study was carried out of patients with spontaneous type 1 Brugada pattern followed up in Arrhythmology consultation at our Hospital. From this population, patients who underwent EPS for stratification of dysrhythmic risk were selected. Clinical and electrocardiographic variables were analyzed. Hospital records and monitoring data from cardiac devices were consulted. Statistical analysis was performed using SPSS 20.0. Results Fourty nine patients were included, with a mean age at the beginning of follow-up of 45±14 years, 40 (82%) of whom were male. In 16 individuals (33%) the EPS was positive with induction of malignant ventricular dysrhythmias. All patients with positive EPS implanted an implantable cardioverter-defibrillator and of the 32 patients with negative EPS, 10 implanted an implantable event recorder. The group of patients with positive EPS had a higher proportion of male patients (88% vs 78%). The median follow-up time was 31 months. The family history of sudden death, family history of BS, or identification of a genetic variant classified as pathogenic or probably pathogenic did not present any relationship with EPS positivity. Of the analyzed electrocardiographic markers, PR interval (178±29 vs 171±27) and QRS duration (119±24 vs 113±15) tended to be longer in patients with positive EPS. Additionally, it was found that 74% of patients with a QRS of less than 120 ms had a negative EPS. In the analysis of the value of EPS in the stratification of dysrhythmic risk, it was found that of all the patients who suffered events (4), 75% had positive EPS. Of the patients with negative EPS, only 3% (1) presented events in the follow-up. However, there was no significant association between these variables. Conclusion In this population, the analysed clinical elements did not correlate with the EPS result. Although there was no statistical significance, there was a tendency for patients with narrower QRS to be more likely to have negative EPS. Accordingly with published data, it was found that the EPS result was not a predictor of events during the follow-up period, which highlights the difficulty of risk stratification in patients with BS. Funding Acknowledgement Type of funding sources: None.

Introduction The arrhythmic risk stratification of patients with repaired Tetralogy of Fallot (TOF) is still controversial. The performance of an electrophysiologic (EP) study before pulmonary valve replacement (PVR), regardless of patient's risk factors, is an extended practice in some centers that is not recommended in current guidelines. The aim of our study was to explore the differences in ventricular tachycardia (VT) inducibility in patients with TOF during programmed ventricular stimulation (PVS) depending on the clinical indication. Methods All patients with repaired TOF who underwent an EP study with PVS between January 2001 and October 2020 were included. EP studies performed in the context of ventricular or supraventricular tachycardia ablations that had been previously diagnosed were excluded. We defined two clinical scenarios for performing the EP study: pre-PVR (performed previous to pulmonary valve replacement) or diagnostic EP study (performed due to high risk symptoms which included palpitations, syncope or presyncope). Baseline clinical information, electrocardiogram, echocardiogram and cardiac MRI parameters were retrospective recorded. Results A total of 139 EP studies with PVS were included; 87 in the pre-PVR group and 52 in the diagnostic EP study group. There was a greater incidence of palpitations, syncope and presyncope in the “Diagnostic EP study” group. Moreover, there were statistical significant differences in right ventricle dimensions and function between groups. The repair surgical approach was similar in both groups. It was detected a statistical significant difference in VT induction between the pre-PVR group and the diagnostic indicated group (16,1% vs 34,6%, p=0,012). Conclusions Differences in VT induction are observed during PVS performing in TOF patients depending on the clinical indication. Symptomatology is an important parameter that must be taken into account in order to decide whether to perform an EP study in this population. Funding Acknowledgement Type of funding sources: None.

A 27-year-old male was referred for further assessment after being evaluated by his general practitioner for isolated palpitations. A twelve-lead electrocardiogram was performed in which sinus rhythm with ventricular pre-excitation were observed. Electrophysiologic study demonstrated the presence of a fasciculoventricular accessory pathway.

Implantable loop recorders allow prolonged and continuous single-lead electrocardiogram recording, with the pivotal addition of remote monitoring. They have significantly shortened time to electrocardiographic diagnosis and appropriate therapy of many bradyarrhythmias/tachyarrhythmias and proved helpful in arrhythmia burden definition, offering invaluable information in the diagnostic workup for syncope and atrial fibrillation. Advanced cardiac signal recording is also possible by transesophageal catheters. They have been used to orient diagnosis during wide and narrow QRS complex tachycardias and also to perform minimally invasive pacing. Intracardiac electrophysiologic study remains, however, essential for diagnosis of several arrhythmias in the perspective of curative catheter ablation.

Syncope in patients with Brugada electrocardiogram pattern may represent a conundrum in the decision algorithm because incidental benign forms, especially neurally mediated syncope, are very frequent in this syndrome similarly to the general population. Arrhythmic syncope in Brugada syndrome typically results from a self-terminating sustained ventricular tachycardia or paroxysmal ventricular fibrillation, potentially leading to sudden cardiac death. Distinguishing syncope due to malignant arrhythmias from a benign form is often difficult unless an electrocardiogram is recorded during the episode. We performed a review of the existing literature and propose a practical approach for diagnosis and treatment of the patients with Brugada syndrome and syncope.

Regular atrial tachycardia (AT) is one of the most important proarrhythmic complications that may occur following left atrial pulmonary vein isolation (PVI). These tachycardias that develop after atrial fibrillation ablation may lead to worse symptoms than those from the original arrhythmia existing prior to the index ablation procedure. Ablation of various types of supraventricular tachycardias without the use of fluoroscopy has been shown to be feasible in both children and adults using three-dimensional mapping systems. We describe the case of a 71-year-old woman who developed a focal AT after a successful PVI procedure. The initial ablation failed with one mapping system. Repeat electrophysiologic study despite antiarrhythmic medications revealed the same focal AT, which was successfully ablated with a different mapping system. Both ablations were performed without fluoroscopy.

At 22 years following heart transplantation, a patient presented with incessant atrial flutter. During electrophysiologic study, 2 simultaneous atrial…, At 22 years following heart transplantation, a patient presented with incessant atrial flutter. During electrophysiologic study, 2 simultaneous atrial arrhythmias were mapped, 1 from the donor and 1 from the recipient’s heart. High-density mapping allowed for rapid identification of electrically abnormal areas, which were successfully ablated, thus restoring sinus rhythm. (Level of Difficulty: Advanced.), Graphical abstract

Background Mitral valve prolapse has been associated with increased risk of ventricular arrhythmias. We aimed to examine whether certain cardiac imaging characteristics are associated with papillary muscle origin of ventricular arrhythmias in these patients. Methods and results We screened electronic medical records of all patients documented to have mitral valve prolapse on either transthoracic echocardiogram (TTE) or cardiac magnetic resonance imaging (CMR) in our center, who also underwent an electrophysiologic study (EPS) between 2007 and 2016. Anterior and posterior mitral leaflet thickness and prolapsed distance were measured on TTE and late gadolinium enhancement (LGE) was assessed on CMR. Patients were categorized as papillary muscle positive (pap (+)) or negative (pap (-)) using EPS. Eighteen patients were included in this study. Of the 15 patients who underwent TTE, a significantly higher proportion of patients in the pap (+) group had an anterior to posterior leaflet prolapse ratio of >0.45 indicating more symmetric leaflet prolapse. There were no differences in anterior or posterior leaflet thickness or prolapse distance between the groups. Patients in the pap (+) group were more likely to be women. Of the 7 patients who underwent CMR, those who were pap (+) were more likely to have LGE in the region of the papillary muscles than those who were pap (-). Conclusion Female gender, more symmetric bileaflet prolapse on TTE, and the presence of papillary muscle LGE on CMR may be associated with papillary muscle origin of ventricular arrhythmias in patients with mitral valve prolapse.

Background The differential diagnosis of a supraventricular tachycardia (SVT) is accomplished using a number of pacing maneuvers. The incidence and mechanism of a single ventricular premature beat (VPB) on initiation and termination of tachycardia were evaluated during programmed electrical stimulation (PES) of the heart in patients with the two most common regular SVTs: atrioventricular re-entrant tachycardia (AVNRT) and orthodromic atrioventricular tachycardia (AVRT). Methods Three hundred and thirty-seven consecutive patients aged above 18 years with an inducible sustained AVNRT or AVRT were prospectively enrolled. Patients with more than one tachyarrhythmia mechanism were excluded. Two hundred and seventeen patients (64.4%) had typical slow/fast AVNRT and 120 (35.6%) had an orthodromic AVRT using a rapidly conducting accessory pathway for V-A conduction. In this cross-sectional study, we specifically report the analysis of tachycardia induction and termination by a single VPB. Results Tachycardia induction with a single VPB during sinus rhythm was seen in 7 of 120 AVRT and in only one of the 217 patients with AVNRT, (5.8% vs. 0.3%, p

A 14-year-old girl with a history of recurrent palpitations and documented wide QRS complex tachycardia was referred for electrophysiologic study and catheter ablation.

We present a case of incessant wide-complex tachycardia in a patient with left-ventricular assist device, and discuss the differential diagnosis with an in-depth analysis of the intracardiac tracings during the invasive electrophysiologic study, including interpretation of the relative timing of the fascicular signals during tachycardia and in sinus rhythm, and interpretation of pacing and entrainment maneuvers.

For older patients with unexplained syncope and chronic bifascicular block (BFB), ACC/HRS and ESC guidelines recommend empiric permanent pacemaker (PPM) implantation, or electrophysiologic study (EPS) and/or implanted loop recorder (ILR) to identify high-degree AV block. Single-center retrospective

International audience; Background: Accessory pathway (AP) ablation is not always easy. Our purpose was to assess the age-related prevalence of AP location, electrophysiological and prognostic data according to this location.Methods: Electrophysiologic study (EPS) was performed in 994 patients for a pre-excitation syndrome. AP location was determined on a 12 lead ECG during atrial pacing at maximal preexcitation and confirmed at intracardiac EPS in 494 patients.Results: AP location was classified as anteroseptal (AS)(96), right lateral (RL)(54), posteroseptal (PS)(459), left lateral (LL)(363), nodoventricular (NV)(22). Patients with ASAP or RLAP were younger than patients with another AP location. Poorly-tolerated arrhythmias were more frequent in patients with LLAP than in other patients (0.009 for ASAP, 0.0037 for RLAP

Background Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) often terminate spontaneously, presumably due to changes in the electrophysiological properties of the reentrant circuit. However, the mechanism of spontaneous termination of these arrhythmias is incompletely understood. Methods We included 70 consecutive patients with reentrant supraventricular tachycardias (35 AVNRT, 35 AVRT) in whom the arrhythmia ended spontaneously during the electrophysiologic study. We determined in each patient the duration of the induced arrhythmia, site of block, beat-to-beat oscillations in tachycardia cycle-length (CL), A-H, H-V, H-A and V-A intervals. Results In 21/34 (62%) patients with AVNRT and 19/30 (63%) with orthodromic AVRT, tachycardia termination was preceded by progressive increase in tachycardia CL due to prolongation of the A–H interval (Mobitz type-I pattern). In 13/34 patients with AVNRT (38%) and 11/30 with orthodromic AVRT (37%), termination occurred suddenly without a preceding change in CL, with block ensuing retrogradely either in the fast AV nodal pathway or the accessory pathway (Mobitz type-II pattern). In 4/5 patients with antidromic AVRT the tachycardia ended at the retrograde limb with previous prolongation of the VA interval. Conclusion Spontaneous termination of AVNRT and AVRT is a time-related phenomenon. Despite different pathways being involved in these two reentrant tachycardias, termination can follow antegrade or retrograde block in similar ratio (60% antegradely and 40% retrogradely). Antegrade block is preceded by prolongation of the AH interval (Mobitz type-I), whereas retrograde block occurs unexpectedly in the retrograde limb (Mobitz type-II). Fatigue of conduction appears to be involved in this phenomenon.

BACKGROUND Ventricular ectopy (VE) originating in the right ventricular outflow tract (RVOT) is a common arrhythmia. Mechanisms triggering or eliminating VE from RVOT are not entirely understood. METHODS AND RESULTS A patient with frequent, symptomatic VE underwent an electrophysiologic study: VE origin was mapped by NavX 3D navigation (St. Jude Medical, Inc., St. Paul, MN, USA). Incidental pressure applied manually to the sternum reproducibly eliminated VE for the time of exposure. Radiofrequency-ablation was successfully performed in the posterior RVOT. CONCLUSION The mechanism resulting in VE suppression remains speculative, since a mechanical alteration of the substrate for VE in the posterior RVOT by sternal pressure seems unlikely. "Mechano-electrical feedback" might have been the mechanism operative in this case.

This article provides a case study of a patient with exercised-induced near syncope. Intracardiac electrophysiologic study confirmed an intra-His block and a pacemaker was implanted.

This article discusses the case of a 69-year-old man with hypertension and diabetes who was admitted for recurrent palpitations and documented atrial flutter. The authors describe the electrophysiologic study and ablation of this case.

BACKGROUND: Detailed information on the profile of patients with Brugada syndrome (BrS) presenting their first arrhythmic event (AE) after prophylactic implantation of an implantable cardioverter-defibrillator (ICD) is limited. OBJECTIVES: The objectives of this study were (1) to compare clinical, electrocardiographic, electrophysiologic, and genetic profiles of patients who exhibited their first documented AE as aborted cardiac arrest (group A) with profiles of those in whom the AE was documented after prophylactic ICD implantation (group B) and (2) to characterize group B patients' profile using the class II indications for ICD implantation established by HRS/EHRA/APHRS expert consensus statement in 2013. METHODS: A survey of 23 centers from 10 Western and 4 Asian countries enabled data collection of 678 patients with BrS who exhibited their AE (group A, n = 426; group B, n = 252). RESULTS: The first AE occurred in group B patients 6.7 years later than in group A (mean age 46.1 ± 13.3 years vs 39.4 ± 15.1 years; P < .001). Group B patients had a higher incidence of family history of sudden cardiac death and SCN5A mutations. Of the 252 group B patients, 189 (75%) complied with the HRS/EHRA/APHRS indications whereas the remaining 63 (25%) did not. CONCLUSION: Patients with BrS with the first AE documented after prophylactic ICD implantation exhibited their AE at a later age with a higher incidence of positive family history of sudden cardiac death and SCN5A mutations as compared with those presenting with aborted cardiac arrest. Only 75% of patients who exhibited an AE after receiving a prophylactic ICD complied with the 2013 class II indications, suggesting that efforts are still required for improving risk stratification.

Focal atrial tachycardias (ATs) from the parahisian region can be successfully ablated from the right atrial septum (RAS), noncoronary cusp (NCC), and right middle septum (RMS). The optimal mapping and ablation strategy for ATs from these sites remains unclear.The purpose of this study was to investigate the electrophysiologic characteristics and optimal ablation sites of parahisian ATs from the RAS, RMS, and NCC.A total of 362 patients with ATs undergoing radiofrequency catheter ablation of ATs were included. A detailed examination including ECG analysis and electrophysiologic study was performed.Overall, 91 patients had a parahisian site of AT origin, and ablation was successful in 86 (94.5%). ATs were successfully eliminated from the RAS in 23, RMS in 19, and NCC in 44. The earliest "A" potential was recorded at the distal His catheter in 69.4% of NCC ATs vs the proximal His catheter in 83.3% of RAS ATs and 86.7% of RMS ATs. Mean timing of the "A" potential of RMS ATs recorded at the His-bundle catheter was -18.25 ± 7.20 ms, which was later than ATs from the RAS (-24.59 ± 8.73 ms) or NCC (-27.08 ± 5.63 ms). For ATs originating from the RAS and RMS, an A/V ratio1.22 predicted safe and successful ablation (sensitivity 88.4%, specificity 91.7%).For parahisian ATs, activation sequence and timing of the "A" on the His catheter can provide clues for the origin of ATs. When ablating at the RAS and RMS, an A/V ratio1.22 identified safe and effective ablation sites.

An isoproterenol infusion was administered during an electrophysiologic study (EPS) in a patient with a history of near syncope, left bundle branch block, and no documented atrioventricular (AV) block. Isoproterenol precipitated classic 2:1 Infra-Hisian AV block most probably proximal to the site of recording a His-Purkinje potential consistent with right bundle branch activity. Paroxysmal AV block also occurred during isoproterenol washout at a different site located distal to the presumed right bundle branch potential. Isoproterenol may be valuable diagnostically in an occasional patient suspected of AV block in whom an EPS is unrevealing and a drug challenge is negative.

Background Atrial electrical conduction properties have been implicated in atrial fibrillation (AF) pathogenesis. Objective The purpose of this study was to prospectively assess the potential association of interatrial conduction time (IACT) with incident AF. Methods The study included persons referred for invasive electrophysiologic study (EPS), aged ≥50 years, without AF history or valvular disease. IACT was defined as the interval between the high right atrium electrogram and the distal coronary sinus atrial electrogram. Results Six hundred twelve subjects were included (median follow-up 43 months, interquartile range 40–47). AF incidence was 21.7 cases per 1000 person-years. IACT was a significant predictor of AF with a c -statistic of 0.770 (95% confidence interval 0.702–0.838). In time-dependent analysis, IACT was a significant stratifier of AF risk (log-rank 28.0, P Conclusion IACT is independently associated with incident AF. The invasive nature of the measurement is a limitation for its use as a clinical risk stratifier (although it could be used in patients referred for EPS), but these results are of interest in themselves because they suggest a strong pathophysiologic connection between atrial conduction times and substrate alterations ultimately leading to AF.

International audience; 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.METHODS:ECGs of 861 patients in whom PS related to an atrioventricular accessory pathway (AP) was identified at electrophysiological study (EPS), were studied.RESULTS:The 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.CONCLUSION:The 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.

Objective Unexplained syncope is a challenge facing electrophysiologists. The prognosis varies widely depending on underlying causes, specially, cardiac ones. We sought to determine the abnormal electrophysiolgic (EP) study results as predictors of prognosis in syncope patients with suspected cardiac cause and risk factors associated with mortality. Methods A total of 227 consecutive patients with unexplained syncope were prospectively enrolled in this study. EP study was performed in 177 patients in base of inclusion criteria. These patients, in whom a cardiac cause of syncope was suspected, underwent EP study and if negative, head-up tilts test (HUTT). Complete follow-up was obtained for 132 patients for 20.0±10.8 months. Results A cardiac cause of syncope was established in 35%, a neurally mediated syncope in 35.6%, and in the rest 29.4% the cause of syncope remained unexplained despite a throughout neurologic and cardiologic evaluation. Logistic analysis revealed that the significant predictors of a cardiac cause of syncope were the absence of prodromal symptoms, left bundle branch block (LBBB), sever left ventricle (LV) dysfunction and male gender. At logistic analysis, the presence of LBBB (OR=6.63; 95% CI: 1.09-40) was significantly associated with outcome of death. Conclusion The present study provides evidence that presence of LBBB, abnormal EP study result and structural heart disease (SHD) have prognostic value in patients with suspected cardiac cause of syncope. The patients with SHD and unexplained syncope who had a negative EP study have a good long-term prognosis even in the presence of LV dysfunction.

Introduction: We investigated electrophysiological properties of the entire right ventricular (RV) endocardium of provoked ventricular tachycardia/ventricular fibrillation (VT/VF) in 2 patients with Brugada syndrome (BS). Methods: N/A. Results: Case 1. Type 3 Brugada type ECG which changed to type 1 ECG by class Ic antiarrhythmic drug, pilsicainide. Electrophysiologic study (EPS): Double ventricular premature stimuli from RVOT (600/260/200 ms) induced VF. The multielectrode array (Ensite, St. Jude Medical) was placed at the right ventricular outflow tract (RVO) and VF was induced again from RVOT (600/224/180 ms). Non-contact mapping during organized rapid VT before degenerating into VF showed that provoked VT arose from RVOT. Case 2: Type 1 Brugada type ECG. EPS: Triple ventricular premature stimuli from RV apex (600/250/220/200 ms) reproducibly induced VF. Non-contact mapping during organized rapid VT showed that provoked VT arose from RV free wall. Conclusion: RVOT and RV free wall appears to be crucial in the initiation and maintenance of VT with degeneration into VF in BS.

Syncope in the setting of infra-hisian block (HVB) is an indication for permanent pacemaker (PPM). However, not all HVB uncovered during electrophysiologic study (EPS) requires a PPM. A 39 year old woman presented with non-prodromal loss of consciousness while driving resulting in an accident.

ObjectiveThe objective of this study was to evaluate the efficacy of a novel approach for endocardectomy during coronary artery bypass graft with surgical ventricular restoration in patients with postinfarction left ventricular aneurysm.MethodsOne hundred sixty-eight patients underwent coronary artery bypass graft with surgical ventricular restoration from 2005 to 2011. Endocardectomy was performed as an integral part of surgical ventricular restoration for the prevention of ventricular tachycardia. The experimental group (surgical ventricular restoration–endocardectomy group; n = 74) underwent preoperative electrophysiologic study with electroanatomic left ventricular mapping. Radiofrequency ablation-induced markings were placed and were used later as guides for performing endocardectomy during coronary artery bypass graft with surgical ventricular restoration. The control group (surgical ventricular restoration group; n = 94) underwent surgical ventricular restoration without endocardectomy.ResultsThe 1-year mortality rates in the surgical ventricular restoration–endocardectomy and surgical ventricular restoration (control) groups were 5% and 13%, respectively. During the postoperative period, 3% of patients in the surgical ventricular restoration–endocardectomy group and 38% of patients in the surgical ventricular restoration group experienced ventricular tachycardia events (P

Background and Objectives Ventricular fibrillation (VF) can inadvertently occur during electrophysiologic study (EPS) or catheter ablation. We investigated the incidence, cause, and progress of inadvertently developed VF during EPS and catheter ablation. Subjects and Methods We reviewed patients who had developed inadvertent VF during EPS or catheter ablation. Patients who developed VF during programmed ventricular stimulation to induce ventricular tachycardia or VF were excluded. Results Inadvertent VF developed in 11 patients (46.7±9.3 years old) among 2624 patients (0.42%); during catheter ablation for atrial fibrillation (AF) in nine patients, frequent ventricular premature beats (VPBs) in one, and Wolff-Parkinson-White (WPW) syndrome were observed in one. VF was induced after internal cardioversion in six AF patients due to incorrect R-wave synchronization of a direct current shock. Two AF patients showed spontaneous VF induction during isoproterenol infusion while looking for AF triggering foci. The remaining AF patient developed VF after rapid atrial pacing to induce AF, but the catheter was accidentally moved to the right ventricular (RV) apex. A patient with VPB ablation spontaneously developed VF during isoproterenol infusion. The focus of VPB was in the RV outflow tract and successfully ablated. A patient with WPW syndrome developed VF after rapid RV pacing with a cycle length of 240 ms. Single high energy (biphasic 150-200 J) external defibrillation was successful in all patients, except in two, who spontaneously terminated VF. The procedure was uneventfully completed in all patients. At a mean follow-up period of 17.4±15.5 months, no patient presented with ventricular arrhythmia. Conclusion Although rare, inadvertent VF can develop during EPS or catheter ablation. Special caution is required to avoid incidental VF during internal cardioversion, especially under isoproterenol infusion.

Background 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. Methods 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. Results 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. Conclusions 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.

The purpose of this study was to evaluate electrophysiologic study (EPS) in risk stratification of relative indications for pacemaker implantation (PMI) after transcatheter aortic valve implantation (TAVI).We reviewed files of all patients who had a left bundle branch block (LBBB) and underwent EPS after TAVI between 3/2009 and 5/2015. The indications for EPS were new-onset LBBB and the presence of an old or a new-onset LBBB associated with either PR prolongation after TAVI (∆PR20 ms) or with "slow" atrial fibrillation (100/min). Pacemakers were implanted when significant infranodal disease was demonstrated. The control group comprised of 55 consecutive patients who underwent TAVI and had an indication for an EPS per our definitions. These patients were discharged without further intervention. All patients were followed during 1 year for the composite endpoint of mortality or PMI after hospital discharge.Indications for EPS were new LBBB (n = 8, 30.8%), new LBBB + ∆PR20 ms (n = 9, 34.6%), baseline LBBB + ∆PR20 ms (n = 7, 26.9%) and new LBBB + slow AF100 bpm (n = 2, 7.7%). Multilevel conduction disturbances involving the AV node (n = 19, 73.1%), the His (n = 3, 11.5%), and the infra-His system (n = 4, 15.4%) were found. Post discharge, there were 5 (9%) deaths and 3 (5.5%) PMI in the control group compared to none in the EPS group corresponding to event-free survival of 85 and 100%, respectively (p = 0.04).Patients with LBBB with or without ∆PR20 ms are at a higher risk of mortality and late PMI at 1-year follow-up. EPS can be used to safely identify patients in whom a PMI is needed.

This article discusses the merits of electrophysiology study (EPS) and/or ablation for asymptomatic preexcitation Wolff-Parkinson-White (WPW) ECG pattern. Sudden deaths in asymptomatic patients are too few to merit broad screening and aggressive intervention. It also discusses the risks of ablation and the low predictive accuracy of EPS. When WPW is an incidental finding, the decision to proceed with investigation and ablation can be made considering patients' situations and preferences. An invasive strategy is targeted at patients concerned about the low risk of life-threatening arrhythmia as a first presentation after a discussion of the risks and benefits.

Background and Objective Among patients with Brugada syndrome (BS) and aborted cardiac arrest, syncope, or inducible ventricular fibrillation at electrophysiologic study (EPS), the only currently recommended therapy is an implantable cardioverter-defibrillator (ICD), but these are not without complications. We assessed the total number of shocks (appropriate and inappropriate) and complications related to ICD in patients with BS. Methods and Results Twenty-five patients implanted with ICD for BS in 6 Gulf centers between January 1, 2002, and December 31, 2010, were reviewed. Implantable cardioverter-defibrillator indication was based on aborted cardiac arrest (24%), syncope (56%), or in asymptomatic patients with positive EPS (20%). During a follow-up of 41.2 ± 17.6 months, 3 patients (all with prior cardiac arrest) had appropriate device therapy. Four patients developed complications; 3 of them had inappropriate shocks. Conclusion In our cohort, appropriate device therapy was limited to cardiac arrest survivors, whereas none of those with syncope and/or positive EPS had arrhythmias. Overall complication rate was relatively high, including inappropriate ICD shocks.

A B S T R A C T Cardiac arrhythmias are prevalent among humans across all age ranges and may occur in the setting of underlying heart disease as well as in structurally normal hearts. While arrhythmias are widely varied in their clinical presentations, they possess shared electrophysiologic properties at the cellular level. The 3 main mechanisms responsible for cardiac arrhythmias are automaticity, triggered activity, and reentry. Although identifying the specific mechanism may at times be challenging for the clinician and require invasive electrophysiologic study, differentiating and understanding the underlying mechanism may be critical to the development of an appropriate diagnosis and treatment strategy.

More than 50% of patients with heart failure die from sudden cardiac death as a result of malignant arrhythmia. T wave alternans (TWA) is a convenient, noninvasive, and inexpensive testing modality, with a higher sensitivity and specificity for sudden cardiac death. Its prediction value for malignant arrhythmia may even exceed electrophysiologic study. Generally, the algorithms of TWA can be divided into frequency-domain and time-domain methods, and the latter has a stronger anti-interference ability. So far, a unified measuring formula and diagnostic criteria about TWA measurements have been created. Large clinical studies in recent years strongly suggest that TWA can predict sudden cardiac death, which can be used as a guide for the implanting of implantable cardioverter-defibrillator. This article reviews the current literature on recording techniques and clinical implications of TWA.

VA Intervals to Distinguish PSVT. Introduction: Usefulness of the interval between the last pacing stimulus and the last entrained atrial electrogram (SA) minus the tachycardia ventriculoatrial (VA) interval in the differential diagnosis of supraventricular tachycardias with long (>100 ms) VA intervals has not been prospectively studied in a large series of patients. Our objective was to assess the usefulness of the difference SA–VA in diagnosing the mechanism of those tachycardias in patients without preexcitation. The results were compared with those obtained using the corrected return cycle (postpacing interval—tachycardia cycle length—atrioventricular [AV] nodal delay). Methods and Results: We included 314 consecutive patients with inducible sustained supraventricular tachycardias with VA intervals >100 ms undergoing an electrophysiologic study. Atrial tachycardias were excluded. Tachycardia entrainment was attempted through pacing trains from right ventricular apex. The SA–VA difference and the corrected return cycle were calculated for every patient. Electrophysiologic study revealed 82 atypical AV nodal reentrant tachycardias (AVNRT) and 237 AV reentrant tachycardias (AVRT) using septal (n = 91) or free-wall (n = 146) accessory pathways (APs). A SA–VA difference >110 ms identified an atypical AVNRT with sensitivity, specificity, positive and negative predictive values of 99%, 98%, 95%, and 99.5%, respectively. Similarly, these values were 88%, 83%, 77%, and 92% for SA–VA difference

RésuméHormis avant l’ablation qu’elle précède systématiquement, l’exploration électrophysiologique semble avoir partiellement perdu de son intérêt et il n’existe pas de recommandations spécifiques récentes la concernant. Elle reste cependant toujours d’actualité à titre diagnostique dans nombre de tachycardies et de bradycardies, mais aussi plus rarement à titre pronostique. Cet article passe en revue et discute les diverses indications actuellement retenues.SummaryBeside just before a catheter ablation of arrhythmia, the electrophysiological study seems to have lost part of its interest, and there are no recent specific guidelines dealing with this particular topic. Yet its interest remains for diagnostic purposes of various bradycardia and tachycardia, but also, though less frequently, as a prognostic tool. This article reviews and discuss its current indications.

Background: In this study we evaluate wide QRS complexes observed during pharmacologic termination of supraventricular tachycardias. Methods: Patients with supraventricular tachycardia, undergoing electrophysiologic study were enrolled. 12 mg of adenosine or 10 mg of verapamil were administered during tachycardia, under continuous monitoring of intaracardiac and surface electrocardiograms. Electrocardiographic features of ventricular ectopy were noted. Results: Seventy-four patients were enrolled. 48 patients were randomized to adenosine and 26 to verapamil. Five different appearance patterns of ventricular ectopy were observed during termination of tachycardias. All wide QRS complexes were of ventricular origin and all of them were observed during the termination of tachycardia. Adenosine more frequently resulted in appearance of ventricular beats (15.4% vs 41.7%, P = 0.003), and this was more frequently observed in patients with atrioventricular nodal reentrant tachycardia. Patients with ventricular beats were younger than those without, in both, verapamil (47.5 ± 15.6 vs 65.0 ± 8.8 years, P = 0.04) and adenosine (40.9 ± 13.8 vs 49.7 ± 16.8, P = 0.03) groups. Left bundle branch block (LBBB)/superior axis morphology was most frequent morphology in adenosine group (55%). Two of 4 patients in verapamil group displayed LBBB/inferior axis QRS morphology and another 2 patients displayed LBBB/superior axis morphology. Conclusions: Noncatheter induced, five different appearance patterns and four distinct morphologies of ventricular origin were observed. Most of them do not directly terminate tachycardia, but are associated with its termination and are not observed in ongoing tachycardia.