Atrioventricular Reentrant Tachycardia Research Articles

Risk stratification of sudden cardiac death in subjects with asymptomatic ventricular preexcitation: diagnostic value of non-invasive and invasive methods

Abstract Introduction In subjects with asymptomatic ventricular preexcitation (AVP) guidelines recommend follow-up by non-invasive methods. However, in some patients accessory pathways (APs) show high-risk invasive parameters and risk of sudden death. Objectives To assess the association between the non-invasive and invasive risk stratification (NIRS and IRS) in AVP patients in our center. Material and methods Retrospective and observational study in 58 patients with AVP, underwent NIRS and IRS. Association between NIRS (electrocardiogram, holter and ergometry testing) and IRS variables (AERP ≤250 msec, SPERRI ≤250 msec, atrioventricular reentrant tachycardia or AF, multiple APs) from the electrophysiological study (EPS), and sensitivity and specificity of NIRS to predict a high-risk EPS were determined. Results Of patients with high-risk EPS (n=41), 55% had a previously low-risk NIRS (n=11) while 78% (n=30) had a high-risk NIRS (p=0.05). A low-risk NIRS had a sensitivity (S) 27% and specificity (E) 47% to predict a high-risk EPS. Conclusions In our population, 1 of every 2 patients with low-risk NIRS presented a high-risk IRS. The NIRS methods present low S and E for risk stratification in AVP patients. Funding Acknowledgement Type of funding sources: None.

Electrophysiological characteristics and catheter ablation of atypical fast-slow atrioventricular nodal reentrant tachycardia using an inferolateral left atrial slow pathway

Abstract Background Understandings of subtypes of atypical atrioventricular nodal reentrant tachycardia (AVNRT) using variants of slow pathway (SP) are still growing. Inferolateral (inf-lat-) left atrial (LA) SP is a rare variant extending into an inf-lat-LA along the mitral annulus (MA). Purpose To characterize an unknown subtype of atypical fast-slow (F/S-) AVNRT using an inf-lat-LA-SP as a retrograde limb (inf-lat-LA-F/S-AVNRT). Methods This Japanese multicenter retrospective study enrolled 4 patients of inf-lat-LA-F/S-AVNRT that was characterized by the earliest site of atrial activation during tachycardia (EAA) between 3 and 6 o'clock along the MA. The diagnosis was made by an exclusion of AV reentrant tachycardia (AVRT) and atrial tachycardia (AT) according to the standard criteria and was confirmed by successful elimination of tachycardia and the inf-lat-LA-SP. Results Surface ECG during tachycardia revealed long RP appearance except one who had short RP due to a short conduction time across the inf-lat-LA-SP. During tachycardia, far-field LA activation preceding near-field activation of coronary sinus (CS) musculature was visible in the CS recording in 2. Retrograde conduction via the inf-lat-LA-SP with a decremental delay was consistently reproducible with ventricular stimulation in 2, 1 of whom had double atrial response, while it was always masked by the presence of a retrograde conduction via the fast pathway in 1 and a retrograde block at the lower common pathway in 1. An injection of a small dose of ATP transiently interrupted a retrograde conduction over the inf-lat-LA-SP, suggesting its ATP-sensitivity. Exclusion of AVRT was made by no resetting of tachycardia with left ventricular extrastimulus in 2 and VA dissociation during overdrive pacing of tachycardia in remaining 2. Exclusion of AT was made by V-A-V response after ventricular entrainment in 1 and termination without atrial capture by ventricular pacing in 2. Ablation of the right-sided SP was unsuccessful to eliminate the tachycardia, but ablation at or near the EAA by transseptal approach was successful to cure the tachycardia, associated with an elimination of a retrograde conduction over the inf-lat-LA-SP following a development of an accelerated junction rhythm in all. Low-frequency potentials preceding local atrial activation, consistent with a retrograde activation via the inf-lat-LA-SP were detected along the MA medial to the EAA in 1. Conclusions Differential diagnosis of tachycardia with the EAA in the inf-lat-LA and especially long RP appearance should include inf-lat-LA-F/S-AVNRT. Presumed arrhythmogenic substrate of the inf-lat-LA-SP seemed to be consistent with the remnant of embryogenic AV ring tissue in the electropharmacological and locational characteristics. Successful elimination of this AVNRT can be obtained by ablation of the inf-lat-LA-SP, but not of the right-sided SP. Funding Acknowledgement Type of funding sources: None.

Return to Flying After Catheter Ablation of Arrhythmic Disorders in Military Aircrew.

INTRODUCTION: Catheter ablation is a widely used and effective treatment option for many tachyarrhythmic disorders. This study analyzes all ablation cases in German military aircrew over a 17-yr period. Recurrence of different arrhythmias and ablation complications were analyzed with an aim of refining specific recommendations for aircrew employment.METHODS: All cases of catheter ablations in pilots and nonpilot aircrew examined at the German Air Force Centre of Aerospace Medicine from 2004 to 2020 were analyzed for sex, age, concomitant diseases, ablated arrhythmias, complications, recurrences, time elapsed from ablation to reablation, number of ablations, and aeromedical disposition, including restrictions in case of a return to flying duties.RESULTS: There were 36 aircrew who underwent catheter ablation; 7 were ablated for 2 or more different arrhythmias; 10 underwent more than one ablation. Ablated arrhythmias included atrioventricular (AV) nodal re-entrant tachycardias, accessory pathways, focal atrial tachycardias, typical and atypical atrial flutter, atrial fibrillation, and premature atrial and ventricular complexes. Recurrence rates differed between the arrhythmias and were lowest in AV re-entrant tachycardias. Complication rates were low.CONCLUSION: In this aircrew cohort, nearly all aircrew were able to return to flying duties following ablation, albeit some with restrictions. Restrictions depended on the underlying arrhythmia, the ablation procedure, and the symptoms prior to ablation. A basic understanding of different arrhythmias, ablation techniques, and long-term success rates is essential for the AME and for the responsible licensing authority. Close cooperation with an electrophysiologist is necessary prior to and after ablation to ensure optimal management of aircrew with arrythmias.Guettler N, Nicol E, Sammito S. Return to flying after catheter ablation of arrhythmic disorders in military aircrew. Aerosp Med Hum Perform. 2022; 93(10):725-733.

Late pacemaker implantation after atrioventricular nodal reentrant tachycardia ablation: A systematic review and meta‐analysis

Catheter ablation (CA) of atrioventricular nodal reentrant tachycardia (AVNRT) is associated with late pacemakers for AV block (AVB). We performed a systematic review and meta-analysis of the pooled incidence of late pacemakers for AVB after CA of AVNRT. Relevant studies were identified from four electronic databases (PubMed, EMBASE, Scopus, and Cochrane Trial Register) from inception to 2022. A random effects model was used to calculate the odds of late pacemakers in CA of AVNRT compared to atrioventricular reentrant tachycardia (AVRT). Of 533 articles screened, 13 were included in systematic review. CA for AVNRT was performed in 16 471 patients (mean age 54 ± 17 years, 63% females), of which 68 (0.4%) underwent pacemaker implantation for late AVB. Meta-analysis was performed in 5 of the 13 studies (mean follow-up duration 7 ± 4 years). Patients who underwent CA of AVNRT were older (58 ± 17 vs. 52 ± 20 years, p < .001), and more likely female (60% vs. 41%, p < .001) than AVRT. Pooled estimates of late pacemakers for AVB were higher in CA of AVNRT than AVRT (0.5% vs. 0.2%, p = .006), with CA in AVNRT associated with almost twofold increased odds of late pacemakers indicated for AVB (odds ratio: 1.94, 95%confidence interval: 1.08-3.47, p = .027) compared to AVRT. AVNRT ablation is safe but associated with a low but definitely increased risk of requiring pacing in the later years due to AVB. This association is confirmed by pooling over 16 000 AVNRT patients receiving clinically indicated ablation and is helpful in providing informed consent for prospective patients undergoing ablation for AVNRT.

Electrogram characteristics at successful cryoablation sites in slow-fast atrioventricular nodal reentrant tachycardia

PurposeCryoablation is a safe alternative to radiofrequency (RF) ablation for slow-fast atrioventricular reentrant tachycardia (AVNRT); however, optimal electrogram parameters for site selection remain unknown. We retrospectively investigated local electrograms for slow pathway (SP) modification in cryoablation. MethodsForty-five consecutive patients with slow-fast AVNRT who underwent cryoablation using a 6-mm-tip catheter were enrolled. Electrogram parameters for sites of successful SP modification (success-sites) were investigated; these included the interval between atrial activation at His and the last deflection of SP potential, defined as the His(A)-SPP interval. In 8 patients, 3-dimensional mapping by multi-electrode catheter was performed pre-ablation for more detailed SP assessment. ResultsTwenty-seven of 45 patients had successful SP modification by 1 cycle of freeze-thaw-freeze cryoablation at a single site with a low amplitude and fragmented SP potential. Among a total of 76 cryoablation sites in all patients, the His(A)-SPP interval at success-sites (45 sites) was significantly longer than that at unsuccess-sites (31 sites) (86 ± 9 vs.78 ± 10 msec, p < 0.0001). The AV amplitude ratio was not significantly different between success-and unsuccess-sites (0.21 ± 0.22 vs.0.25 ± 0.23, p = 0.429). The cutoff value of the His(A)-SPP interval for successful cryoablation was 82 msec with a sensitivity of 0.67 and specificity of 0.71 (AUC: 0.739; 95%CI: 0.626–0.852; p < 0.0001). Three-dimensional mapping in all 8 patients showed that sites with the most delayed atrial activation and the last deflection of the fragmented SP potential within the Koch's triangle coincided with success-sites. ConclusionA longer His(A)-SPP interval and fractionated SP potential were characteristics of successful cryoablation for SP modification in slow-fast AVNRT.

Three-dimensional electroanatomically guided slow pathway elimination is associated with procedural improvements and clinical benefit in atrioventricular node reentrant tachycardia patients.

Slow pathway (SP) ablation, in the context of atrioventricular node reentrant tachycardia (AVNRT) treatment could result in either complete elimination or only modification of the SP with ambiguity regarding associated benefits. Three-dimensional electroanatomical mapping (3D-EAM) may be used adjunctively aiming to complete SP elimination. Our purpose was to compare a 3D-EAM-based strategy targeting SP elimination to the conventional fluoroscopic approach with respect to clinical outcomes. One hundred and two consecutive AVNRT patients (36 males, mean age 53.2 ± 13.7 years) underwent in two successive periods a conventional fluoroscopic ablation approach (n=42) or a 3D-EAM-guided ablation focusing on complete SP elimination (n=60). Several procedural parameters improved with 3D-EAM use, including fluoroscopy time (2.4 ± 4.7min vs. 13 ± 4.5min), dose-area product (1061 ± 3122 μGy × m2 vs. 5002 ± 3032 μGy × m2) and slow pathway elimination frequency (95% vs. 50%, all p < .001). Procedural time was slightly prolonged in the 3D-EAM group (101 ± 31 min vs. 87 ± 24 min, p=.013). Two major complications occurred in the conventional group. Altogether, over a mean follow-up of approximately 2.7 years, recurrence occurred in 6 of 42 (14.3%) in the conventional group as compared to 1 of 62 (1.7%) in the EAM-based group (p=.019). In the Kaplan-Meier analysis, time-to-event was significantly longer for the EAM-based patients (p < .030). Moreover, the EAM-based strategy was associated with less redo procedures' rates (9.5% in the non-EAM group vs. 0% in the EAM group, p=.026). The present study showed that an EAM-based SP elimination strategy is not only feasible and safe but it is also accompanied by improved clinical outcomes in the setting of AVNRT ablation.

The high-density grid catheter: A safe adjunctive tool in pediatric and complex congenital heart disease patients.

The safety and utility of the Advisor™ High-Density Grid mapping catheter (HDGC) in children and congenital heart disease (CHD) patients are not well described. A single-center retrospective cohort study of pediatric and CHD patients undergoing electrophysiology study and ablation to determine the effect of HDGC use on outcomes including complications, fluoroscopy use, procedure duration, acute ablation success, and arrhythmia recurrence. HDGC was used in 74/261 (28.3%) cases. HDGC subjects differed by median age (17 vs. 13 years; p < 0.001),weight (68 vs. 50 kg; p < 0.001), and prevalence of significant CHD (42% vs. 3%; p < 0.001). Arrhythmia substrates were dissimilar: HGDC cases had higher frequencies of intra-atrial re-entrant tachycardia (25.7% vs. 0.5%), atrial flutter (8.1% vs. 1.1%), ectopic atrial tachycardia (13.5% vs. 3.7%), and premature ventricular contractions (9.5% vs. 0.5%), and lower incidences of atrioventricular re-entrant tachycardia (16.2% vs. 46.1%). Complications were rare (n = 5, 1.9%) with no significant difference between groups (p = 1.00). Procedure duration-but not fluoroscopy exposure-was significantly longer in HDGC cases (median 256 vs. 216 min, p < 0.001). Acute success was lower (93.2% vs. 99.4%; p = 0.01) and recurrences higher (13.2% vs. 3.8%; p = 0.016) in HDGC compared to non-HDGC cases. HDGC use in children and CHD patients is safe and not associated with higher complication rates. The lower acute success and higher recurrence rates in HDGC cases likely reflect a bias toward HDGC use in more complex arrhythmia substrates rather than less favorable ablation outcomes.

Forward-Solution Noninvasive Computational Arrhythmia Mapping: The VMAP Study.

The accuracy of noninvasive arrhythmia source localization using a forward-solution computational mapping system has not yet been evaluated in blinded, multicenter analysis. This study tested the hypothesis that a computational mapping system incorporating a comprehensive arrhythmia simulation library would provide accurate localization of the site-of-origin for atrial and ventricular arrhythmias and pacing using 12-lead ECG data when compared with the gold standard of invasive electrophysiology study and ablation. The VMAP study (Vectorcardiographic Mapping of Arrhythmogenic Probability) was a blinded, multicenter evaluation with final data analysis performed by an independent core laboratory. Eligible episodes included atrial and ventricular: tachycardia, fibrillation, pacing, premature atrial and ventricular complexes, and orthodromic atrioventricular reentrant tachycardia. Mapping system results were compared with the gold standard site of successful ablation or pacing during electrophysiology study and ablation. Mapping time was assessed from time-stamped logs. Prespecified performance goals were used for statistical comparisons. A total of 255 episodes from 225 patients were enrolled from 4 centers. Regional accuracy for ventricular tachycardia and premature ventricular complexes in patients without significant structural heart disease (n=75, primary end point) was 98.7% (95% CI, 96.0%-100%; P<0.001 to reject predefined H0 <0.80). Regional accuracy for all episodes (secondary end point 1) was 96.9% (95% CI, 94.7%-99.0%; P<0.001 to reject predefined H0 <0.75). Accuracy for the exact or neighboring segment for all episodes (secondary end point 2) was 97.3% (95% CI, 95.2%-99.3%; P<0.001 to reject predefined H0 <0.70). Median spatial accuracy was 15 mm (n=255, interquartile range, 7-25 mm). The mapping process was completed in a median of 0.8 minutes (interquartile range, 0.4-1.4 minutes). Computational ECG mapping using a forward-solution approach exceeded prespecified accuracy goals for arrhythmia and pacing localization. Spatial accuracy analysis demonstrated clinically actionable results. This rapid, noninvasive mapping technology may facilitate catheter-based and noninvasive targeted arrhythmia therapies. URL: https://www. gov; Unique identifier: NCT04559061.

The advantage of the mini-electrode-equipped catheter for the radiofrequency ablation of paroxysmal supraventricular tachycardia.

Novel ablation catheters equipped with mini-electrodes (ME) offer high resolution mapping for target tissue. This study aimed to evaluate the mapping performance and efficacy of ME catheters in radiofrequency ablation (RFA) of paroxysmal supraventricular tachycardias (PSVTs). We prospectively enrolled 136 patients undergoing RFA of PSVT including 76 patients with atrioventricular nodal reentrant tachycardia (AVNRT) and 60 patients with atrioventricular reentrant tachycardia (AVRT) or Wolff-Parkinson-White (WPW) syndrome. Patients were randomized to the ME group (ablation using ME catheters) or the control group (ablation using conventional catheters). The number of ablation attempt and cumulative ablation time to ablation endpoints, which was defined as an emergence of junctional rhythm in AVNRT or accessory pathway (AP) block in AVRT/WPW syndromes were compared. During ablation procedures, discrete slow pathway or AP electrograms were found in 27 (39.7%) patients in the ME group and 13 (19.1%) patients in the control group. The primary study outcomes were significantly lower in the ME group (ablation attempt number: 2.0 [1-4] vs. 3.0 [2-7] in the ME and control group, p = .032; ablation time: 23.5 [5.0-111.5] vs. 64.5 [16.0-185.0] s, p = .013). According to the PSVT diagnosis, ablation time to junctional rhythm was significantly shorter in the ME group in AVNRT. In AVRT/WPW syndrome, both ablation attempt number and ablation time to AP block were nonsignificantly lower in the ME group. The novel ME catheter was advantageous for identifying pathway potentials and reducing initial ablation attempt number and ablation time to reach acute ablation endpoint for PSVTs(ClinicalTrials.gov number, NCT04215640).

Randomized comparison of atrioventricular node re-entry tachycardia and atrial flutter catheter ablation with and without fluoroscopic guidance: ZeroFluoro study.

Interventional cardiology procedures may expose patients and staff to considerable radiation doses. We aimed to assess whether exposure to ionizing radiation during catheter ablation of supraventricular tachycardia (SVT) can be completely avoided. In this prospective randomized study, patients with SVT (atrioventricular re-entrant tachycardia n = 94, typical atrial flutter n = 29) were randomly assigned in a 1:1 ratio to catheter ablation with conventional fluoroscopic guidance (CF group) or with the EnSite Precision mapping system [zerofluoro (ZF) group]. Acute procedural parameters, increased stochastic risk of cancer incidence and 6-month follow-up data were assessed. Between May 2019 and August 2020, 123 patients were enrolled. Clinical parameters were comparable. Median procedural time was 60.0 and 58.0 min, median fluoroscopy time and estimated median effective dose were 240 s vs. 0 and 0.38 mSv vs. 0 and arrhythmia recurrence was 5% and 7.9% in the CF and ZF groups, respectively. The acute success rate was 98.4% in both groups. No procedure-related complications were reported. At an average age of 55.5 years and median radiation exposure of 0.38 mSv, the estimate of increased incidence was approximately 1 in 14 084. The estimated mortality rate was 1 per 17 857 exposed persons. The procedural safety and efficacy of the zero-fluoroscopic approach are similar to those of conventional fluoroscopy-based ablation for atrioventricular nodal re-entrant tachycardia and atrial flutter. Under the assumption of low radiation dose, the excessive lifetime risk of malignancy in the CF group due to electrophysiology procedure is reasonably small, whilst totally reduced in zero fluoroscopy procedures.

Safety and effectiveness of a novel dielectric mapping system: one-year, two chinese centers experiences

BackgroundThe KODEX-EPD system is a novel, dielectric three-dimensional mapping system. We aim to illustrate the feasibility, safety, and outcomes of ablation using the KODEX-EPD system.MethodsA total of 272 patients with supraventricular arrhythmias were enrolled and underwent catheter ablation using the KODEX-EPD system from October 2020 to July 2021. The feasibility, safety, and ablation outcomes were analyzed.ResultsOf the enrolled patients, 15 (5.4%) had atrial tachycardia (AT), 88 (31.4%) had atrioventricular reentrant tachycardia (AVRT), 141 (50.4%) had atrioventricular nodal reentrant tachycardia (AVNRT), 34 (12.1%) had atrial fibrillation (AF), and 9 (3.2%) had atrial flutter (AFL). All AF patients included were first-do-pulmonary vein isolation (PVI); there were 26 paroxysmal AF and 8 persistent AF. All patients achieved immediate success of ablation. The mean follow-up duration was 11.8 ± 2.4 months. One patient (1.1%) in the AVRT subgroup and two patients (1.4%) in the AVNRT subgroup experienced recurrence. When considering a three-month blanking time, the estimated freedom of AF at one-year post-ablation with and without AADs was 75.7% and 70.4%, respectively. The Kaplan–Meier analysis showed no significant difference in the overall AF recurrence (log-rank; P = 0.931) or AAD-free AF recurrence (log-rank; P = 0.841) between RFCA and cryoablation. One patient had mild pulmonary embolism. None of the patients died or had a cerebrovascular event in the periprocedural period.ConclusionsThis retrospective, two-center study demonstrated that catheter ablation of supraventricular arrhythmias using the KODEX-EPD system is feasible, safe, and effective.Trial registration Retrospectively registered.

Postnatal recurrence and transesophageal inducibility of prenatally treated fetal supraventricular tachycardia.

Antiarrhythmic treatment of fetal supraventricular tachycardia (SVT) is used to prevent morbidity and mortality. The postnatal management of survivors is often arbitrary and varied. The purpose of this study was to examine the utility of a risk-based postnatal management strategy. Sixty-six prenatally treated newborns with fetal long or short ventriculoatrial tachycardia were reviewed. Postnatal diagnoses included atrioventricular reentrant tachycardia, atrial ectopic tachycardia, and permanent junctional reciprocating tachycardia. Unless SVT persisted to birth, early neonatal observation without treatment was recommended. For newborns without spontaneous arrhythmia after ≥2 days of observation, inducibility was tested by transesophageal pacing study (TEPS). Postnatal therapy was advised for spontaneous or inducible SVT. Characteristics associated with these outcomes were analyzed. Twenty-eight patients (42%) experienced SVT at or early after birth, which was associated with fetal long ventriculoatrial tachycardia (odds ratio [OR] 6.8; 95% confidence interval [CI] 1.88-24.57; P = .0029); delayed in utero cardioversion with treatment (median 11 days vs 5.5 days; P < .0001); prenatal treatment with multiple antiarrhythmics (OR 4.42; 95% CI 1.56-12.55; P = .0059); and postnatal atrial ectopic tachycardia/permanent junctional reciprocating (OR 18.0; 95% CI 2.11-153.9; P = .0013). Of the 38 neonates undergoing TEPS, 19 (50%) had inducible tachyarrhythmias. Recurrence of SVT during infancy or childhood was documented in 4 of 6 patients with SVT at birth (66%), 8 of 22 patients with early neonatal SVT (36%), 4 of 19 patients with inducible SVT (21%), and 0 of 19 untreated patients without inducible SVT (0%) (P= .0032). The postnatal risk of SVT is related to the arrhythmia mechanism and prenatal treatment response. In newborns without spontaneous SVT, TEPS may be useful to guide the need for postnatal treatment on the basis of SVT inducibility.

Author's reply: A novel mechanism of sudden infant death syndrome during atrioventricular reentrant tachycardia: a case report.

Author's reply: A novel mechanism of sudden infant death syndrome during atrioventricular reentrant tachycardia: a case report.

Negative SA-VA difference during entrainment of a supraventricular tachycardia: a new criterion for the diagnosis of focal atrial tachycardia

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Ventricular overdrive pacing during tachycardia is one of the most common and useful maneuvers to assess de differential diagnosis of supraventricular tachycardia (SVT). Focal atrial tachycardia (FAT) usually presents long ventriculo-atrial (VA) interval, which is a passive interval since FAT is not an atrio-ventricular reentry. Therefore, during ventricular entrainment of a FAT, the stimulus-atrial (SA) interval will depend solely on the retrograde VA conduction time, if retrograde conduction exists. This retrograde conduction time is usually shorter than the VA Interval during tachycardia, thus being able to cause a negative SA-VA difference. This does not occur in other types of SVT, where the SA-VA difference helps to differential diagnosis, but positive values have been described. Purpose Our aim was to analyze whether the SA-VA value discriminates FAT from the other types of SVT, in patients with SVT and VA conduction when stimulating the ventricle during tachycardia. Methods Multicenter data of SVT entrainment were collected retrospectively, including FAT, atrioventricular nodal reentry tachycardia (AVNRT), and atrioventricular reciprocating tachycardia (AVRT). The numeric value of SA-VA difference was calculated for each case. The best SA-VA cut-off point for the diagnosis of TAF was determined, evaluating the sensitivity and specificity of this value for the diagnosis of TAF with respect to the gold standard (classical criteria). Results Continuous ventricular pacing during tachycardia succeeded in accelerating the atrium to the pacing rate in 80 cases out of the total studied cases: 32 (40%) AVNRT, 28 (35%) AVRT and 20 (25%) FAT. All FAT cases had a negative SA-VA value and all AVNRT and AVRT cases obtained positive SA-VA (Figure 1). SA-VA value lower than 0 ms was the best cut-off point (using ROC curve, Figure 2) with an area under the curve of 1. SA-VA difference lower than 0 ms (or negative SA-VA difference) showed 100% sensitivity and specificity for the diagnosis of FAT. Conclusions Negative SA-VA difference is a new and accurate criterion for the diagnosis of focal atrial tachycardia.

P5 ACCESSORY PATHWAYS HIGH–DENSITY MAPPING IN WOLFF–PARKINSON–WHITE SYNDROME

Abstract Wolff–Parkinson–White syndrome is a common condition characterized by atrioventricular accessory pathways (AP), which can be asymptomatic or can be responsible for atrioventricular reentrant tachycardia or rapid conduction of atrial fibrillation to the ventricles: for this reason, patients are referred for catheter ablation procedures. Although success rates of ablation are &amp;gt;95%, late recurrences can occur in 2–21% of cases mainly depending on the anatomical position. Current approaches remain suboptimal, and when failures occur, they may be due to technical difficulties such as poor contact or catheter stability, inability to access the target site as well as mapping errors resulting in inaccurate location of the AP itself. High–density mapping represents an alternative approach to mapping arrhythmias since the collection of a high density of points allows pathway conduction to be mapped more efficiently. The use of a new software called open–window mapping proved to be reliable in the localization of AP and therefore in the determination of the effective ablation site. A 41–year–old male patient was referred to our Centre following the ECG finding of manifest ventricular preexcitation and short–lasting paroxysmal palpitations. In the Electrophysiology Lab, the diagnostic catheters were inserted with the “fluoroless” technique using the EnSite Precision™ mapping system (Abbott): the ECG and the endocavitary electrograms were indicative of a right Parahissian accessory pathway. The mapping was performed with a multipolar catheter (Advisor™ HD Grid). Once the location of the pathway had been estimated, the roving acquisition interval (RAI) was set according to the expected position of atrial and ventricular electrogram. The RAI window was centered at this point and was opened in both directions (open window mapping) to fully include signals leading up to and traveling away from the AP. It accurately showed the location of the pathway just few millimeters from the Hissian potential. The baseline electrophysiological study revealed an effective antegrade refractory period (PREAP) of 320 msec. In isoproterenol, antegrade PREAP was reduced to 300 msec and inducibility of arrhythmias was not observed. Therefore, in consideration of the poor conductive properties and the non–inducibility of arrhythmias, as well as the anatomical site near the conduction system, it was decided not to proceed with the ablation due to the significant risk of atrio–ventricular block.

PO-717-02 TRANS-HEPATIC ‘BODY-FLOSSING’ TO OBTAIN ACCESS IN A PATIENT WITH VENOUS OCCLUSIONS FOR SUPRAVENTRICULAR TACHYCARDIA ABLATION

Trans-hepatic access (THA) can be performed for ablations in patients with femoral venous occlusions. In the setting of additional superior vena cava (SVC) occlusion, obtaining a second access can be challenging. To describe retrograde crossing of a chronic total venous occlusion (CTVO) followed by superior snaring after THA. n/a A 45-year-old female with a history of end-stage renal disease presented with recurrent supraventricular tachycardia refractory to medications. She had dialysis performed at different times via all 4 extremities and had known inferior CTVO. THA was obtained to gain access into the heart (A, blue arrows). Right internal jugular vein (IJV) was occluded; the left IJV vein was accessed, however, there was evidence of SVC stenosis (B, yellow dotted line), and a wire could not be advanced antegradely. Using a Glidewire from the THA, the stenosis was crossed retrogradely (C, yellow arrows). From the left IJV sheath, the wire tip was snared (D, white arrow), and pulled out (Figure 1E, green arrows). Once through-and-through access was obtained, a long sheath was advanced over the wire into the right atrium (F, red arrows) through which another decapolar catheter (G-H, orange arrow) was placed and with the help of the THA decapolar coronary sinus catheter (G, asterisk), the diagnosis of typical atrioventricular node reentrant tachycardia was confirmed. Following this, the THA decapolar catheter was replaced by an ablation catheter (H, red arrow) for successful slow pathway modification. Obtaining venous access in addition to the THA can be challenging in patients with superior and inferior venous stenosis. Retrograde crossing of CTVO scan be performed after THA, and with the help of snaring, additional access can be obtained.

Near zero vascular complications using echo-guided puncture during catheter ablation of arrhythmias: A retrospective study and literature review.

BackgroundCatheter ablation (CA) is routinely used for the treatment of arrhythmias. Vascular complications are the most common complications during these procedures. Previous data reported that ultrasound (US)‐guided puncture is a useful method to avoid vascular complications. We reported our experience using US‐guided puncture in patients undergoing CA for arrhythmias.MethodsA total of 273 patients (mean age 57 ± 17 years; 58% male) were referred to our center for CA of arrhythmias from January 2016 to December 2019. All procedures were performed by expert operators, and US‐guided vascular access was performed on all patients. Doppler sonography was performed the day after the procedure on all patients.ResultsEighty‐four patients (31%) underwent atrioventricular nodal reentrant tachycardia ablation, 49 patients (18%) atrioventricular reentrant tachycardia ablation, 14 patients (5%) atrial tachycardia ablation, 25 patients (9%) atrial flutter ablation, 63 patients (23%) atrial fibrillation ablation, and 38 patients (14%) ventricular tachycardia ablation. Vascular pseudo‐aneurysms and arteriovenous fistula were defined as major complications; furthermore, venous thrombosis and inguinal hematomas were as defined minor complications. The percentage of major vascular complications was 0.3% (1 arteriovenous fistula) and the percentage of minor vascular complications was 0.3% (1 venous thrombosis).DiscussionUltrasound‐guided vascular puncture in patients undergoing CA is useful to improve procedural success and reduce complications.

Atypical fetal junctional ectopic tachycardia: a case report and literature review

BackgroundJunctional ectopic tachycardia (JET) is caused by ectopic rhythms, originating in the atrioventricular node, typically with heart rate between 200 and 250 bpm. Herein, we present a case of fetal JET with normal fetal heart rate and a review of nine cases.Case presentationA 32-year-old, gravida 2, para 1, woman in whom fetal JET could not be diagnosed prenatally because the fetal heart rate was within the normal range. The fetus was diagnosed with premature restriction of the foramen ovale, and a cesarean section was performed, owing to the right heart overload that was characterized by fetal ascites and abnormal fetal Doppler velocity. Postnatally, the female neonate was diagnosed with JET on a 12-lead electrocardiogram, which revealed a neonatal heart rate of 158 bpm with narrow QRS and atrioventricular dissociation. After failure to respond to amiodarone therapy, she was treated with flecainide, which controlled the JET rate from 120 to 150 bpm. Fetal tachycardia with ventriculo-atrial (VA) dissociation or 1:1 VA conduction with a shorter VA interval than that of atrioventricular reentrant tachycardia confirmed the diagnosis of fetal JET.ConclusionsJET should be suspected even in the absence of tachycardia in patients with ductus venosus and pulmonary vein retrograde flow or tricuspid and mitral regurgitation without a cardiac anomaly, as tachycardia might sometimes be intermittent in cases of JET.

Successful radiofrequency ablation of swallowing-induced atrial tachycardia arising from left superior ganglionated plexus.

A man in his early 40s developed palpitations brought on by swallowing and was found to have short runs of atrial tachycardia induced by swallowing solid food. Atrial tachycardia during swallowing was documented on electrocardiography and 24-hour Holter monitoring. No structural heart disease or esophageal disorders were found by echocardiography. The patient then underwent an electrophysiological study and catheter ablation. We mapped the left atrium with a multipolar mapping catheter while the patient swallowed bread and found that the earliest endocardial breakthrough was on the left anterior superior atrium, where the left superior ganglionated plexus was located. We successfully eliminated the paroxysmal atrial tachycardia at this site. Interestingly, in the process of ablation, atrioventricular node reentrant tachycardia was triggered. After the slow-pathway ablation procedure, no further tachycardia was induced.

Antiarrhythmic Medication in Neonates and Infants with Supraventricular Tachycardia

Supraventricular tachycardia (SVT) is the most common arrhythmia in neonates and infants, and pharmacological therapy is recommended to prevent recurrent episodes. This retrospective study aims to describe and analyze the practice patterns, effectiveness, and outcome of drug therapy for SVT in patients within the first year of life. Among the 67 patients analyzed, 48 presented with atrioventricular re-entrant tachycardia, 18 with focal atrial, and one with atrioventricular nodal re-entrant. Fetal tachycardia was reported in 27%. Antiarrhythmic treatment consisted of beta-receptor blocking agents in 42 patients, propafenone in 20, amiodarone in 20, and digoxin in 5. Arrhythmia control was achieved with single drug therapy in 70% of the patients, 21% needed dual therapy, and 6% triple. Propafenone was discontinued in 7 infants due to widening of the QRS complex. After 12 months (6–60), 75% of surviving patients were tachycardia-free and discontinued prophylactic treatment. Patients with fetal tachycardia had a significantly higher risk of persistent tachycardia (p: 0.007). Prophylactic antiarrhythmic medication for SVT in infancy is safe and well tolerated. Arrhythmia control is often achieved with single medication, and after cessation, most patients are free of arrhythmias. Infants with SVT and a history of fetal tachycardia are more prone to suffer from persistent SVT and relapses after cessation of prophylactic antiarrhythmic medication than infants with the first episode of SVT after birth.