Left Lateral Accessory Pathway Research Articles

Case series of catheter-based arrhythmia ablation in 13 pregnant women.

Catheter ablation is a rarely used procedure to treat arrhythmias during pregnancy. In the case of maternal arrhythmia during pregnancy, zero-fluoroscopic catheter ablation is preferable to medical treatment. Between April 2014 and September 2021, we examined the demographic data, procedural parameters, and fetal and maternal outcomes in pregnant women undergoing ablation at the Gottsegen National Cardiovascular Center and University of Pécs Medical School, Heart Institute. Fourteenprocedures (14 electrophysiological studies [EPS], 13 ablations) performed on 13 pregnant women (age 30.3 ± 5.2 years, primipara n = 6) were studied. During EPS, 12 patients had inducible arrhythmias. Atrial tachycardia was confirmed in three, atrioventricular re-entry tachycardia via manifest accessory pathway (AP) in three, and via concealed AP in one case. Atrioventricular nodal re-entry tachycardia was confirmed in three and sustained monomorphic ventricular tachycardia in two cases. Eleven radiofrequency ablation (84.6%) and two cryoablation (15.4%) were performed. The electroanatomical mapping system was used in all cases. Transseptal puncture was performed in two cases (15.4%) due to left lateral APs. The mean procedure time was 76.0±33.0 minutes. All procedures were performed without fluoroscopy. No complications occurred. During the follow-up, arrhythmia-free survival was achieved in all cases, but in two patients, we used antiarrhythmic drugs (AADs) to achieve it. APGAR score was within the normal range in all cases [median (interquartile range),9.0/10.0 (9.0-10.0/9.3-10.0)]. Zero-fluoroscopic catheter ablation was an effective and safe treatment option for our 13 pregnant patients. Catheter ablation may have less side effects on fetal development than the use of AADs during pregnancy.

Case series of catheter-based arrhythmia ablation in pregnant women

Abstract Funding Acknowledgements Type of funding sources: None. Background Antiarrhythmic drugs (AADs) should be used with caution in treating arrhythmias during pregnancy because of side effects, but catheter ablation is a rarely used procedure. Aim To investigate the efficacy and safety of catheter ablation in cardiac arrhythmias during pregnancy. Methods A double-center retrospective case series study was performed. We studied a population of patients undergoing catheter ablation for cardiac arrhythmias during pregnancy between April 2014 and September 2021 in two cardiovascular centers in Hungary. Results 14 procedures [14 electrophysiology studies (EPS), 13 ablations] performed on 13 gravid women (age 30.3±5.2 years, primipara n=6) were studied. The mean gestation period was 24.0 (20.0-27.0) weeks at the time of intervention, and the mean duration of arrhythmia was 44.0±53.0 months. Of the pregnant women 38.5% had comorbidities and 15.4% had structural heart disease. During EPS, 12 patients had inducible arrhythmias. Focal atrial tachycardia was confirmed in 3, AVRT via manifest accessory pathway (AP) in 3 (WPW syndrome) AVRT via counceled AP in 1 case. AVNRT was confirmed in 3, sustained ventricular tachycardia in 2 cases (25-25-8.3-25-16.6%). 11 radiofrequency ablations (RFA) (84.6%) and 2 cryoablations (15.4%) were performed. The electroanatomical mapping system was CARTO in 11 cases (84.6%) and NavX-EnSite in 2 cases (15.4%). Intracardiac echocardiography (ICE) was used in 5 cases (38.5%). Transseptal puncture was performed in 2 cases (15.4%) due to left lateral AP. The average procedure time was 76.0±33.0 min. All the procedures (100.0%) were performed without fluoroscopy. No complications occurred during the procedures. In the long term, arrhythmia-free survival was achieved in all cases (100.0%), but in two patients, we used AADs to achieve freedom of arrhythmia. With AADs, the mean birth weight was lower than that of fetuses of gravidas not taking drugs (2110±1314 vs. 3253±458 g). APGAR was within the normal range in all cases [9.0/10.0 (IQR) (9.0-10.0/9.3-10.0)]. Conclusions Zero-fluoroscopic catheter ablation during pregnancy is an effective and safe treatment method when needed. Catheter ablation for persistent maternal arrhythmias has a more beneficial effect on fetal development than the use of AADs. Indeed, long-term outcome and safety need to be investigated in a larger patient population.

AP-452681-4 UNUSUAL INITIATION OF ORTHODROMIC ATRIOVENTRICULAR REENTRANT TACHYCARDIA WITH A JUNCTIONAL BEAT

Spontaneous initiation of orthodromic atrioventricular reentrant tachycardia (AVRT) is commonly noted with premature ventricular beat (PVC). In the lab it can be initiated with programmed atrial or ventricular stimulation. We report the initiation of AVRT (with left lateral accessory pathway) with a junctional beat. Case report A 69-year-old male with history of Parkinson’s, HTN, who has had palpitations for few years. Event monitor showed narrow and wide complex tachycardia and he was scheduled for electrophysiology (EP) study and catheter ablation. He presented in sinus rhythm. EP study revealed normal AH and HV intervals with no evidence of preexcitation. Narrow complex supraventricular tachycardia (SVT) initiated spontaneously as noted in the Figure. SVT (short RP) was also initiated with ventricular and atrial extra stimuli without critical AH dependence. There was eccentric atrial activation during SVT with the earliest atrial activation on distal CS. Ventricular overdrive pacing (VOD) during SVT lead to VAV response ruling out atrial tachycardia. There was LBBB during SVT that increased the VA time from 94 ms to 170 ms. The tachycardia terminated with single fused PVC with VA block. Based on these findings a diagnosis of AVRT was made and the concealed left lateral accessory pathway was ablated at 1’o clock on mitral annulus via transseptal catheterization. This case illustrates spontaneous initiation of AVRT using a left lateral accessory pathway with a junctional beat that conducted retrogradely through the accessory pathway. This is a novel finding that has not been demonstrated prior to this. Hence a junctional beat can spontaneously initiate AVRT similar to a PVC. Similarly JPC can initiate AVNRT especially during ablation at the slow pathway region and should not be presumed to be junctional tachycardia.

Validation of qrs-polarity algorithm with special emphasis in parahisian pathways.

In 1996 Iturralde et al. published an algorithm based on the QRS polarity to determine the location of the accessory pathways (AP), this algorithm was developed before the massive practice of invasive electrophysiology. To validate the QRS-Polarity algorithm in a modern cohort of subjects submitted to radiofrequency catheter ablation (RFCA). Our objective was to determinate its global accuracy and its accuracy for parahisian AP. We conducted a retrospective analysis of patients with Wolff-Parkinson-White (WPW) syndrome who underwent an electrophysiological study (EPS) and RFCA. We employed the QRS-Polarity algorithm to predict the AP anatomical location and we compared this result with the real anatomic location determined in the EPS. To determine accuracy, the Cohen's kappa coefficient (k) and the Pearson correlation coefficient were used. A total of 364 patients were included (mean age 30 years, 57% male). The global k score was 0.78 and the Pearson's coefficient was 0.90. The accuracy for each zone was also evaluated, the best correlation was for the left lateral AP (k of 0.97). There were 26 patients with a parahisian AP, who showed a great variability in the ECG features. Employing the QRS-Polarity algorithm, 34.6% patients had a correct anatomical location, 42.3% had an adjacent location and only 23% an incorrect location. The QRS-Polarity algorithm has a good global accuracy; its precision is high, especially for left lateral AP. This algorithm is also useful for the parahisian AP.

The characteristics of pre-excitation syndrome concomitant with atrial tachyarrhythmia and the effect of radiofrequency ablation.

Wolff-Parkinson-White (WPW) concomitant with atrial tachyarrhythmia (ATA) has not been systemically characterized. Detailed electroanatomical mapping of the right atrium (RA) and/or left atrium (LA) was performed using three-dimensional mapping and the accessory pathway (AP) was mapped. WPW syndrome with ATA was diagnosed in 11 patients (median age 60 years). The characteristic of unidirectional anterograde conduction over the AP was displayed in nine patients, six of whom were intermittent. Sustained atrial tachycardia, that is, counterclockwise atrial flutter (AFL) with a median tachycardia cycle length (TCL) of 225 (220-275) ms, was mapped in eight patients; furthermore, "figure 8" right atrial reentry was mapped with TCL 250ms in one patient with a surgical history of ventricular septal defect repair. The remaining two patients underwent mitral annulus-dependent AT after paroxysmal atrial fibrillation (PAF) ablation and LA micro-reentry AT, respectively. In four patients, the location of the APs was left posterior. Left-lateral APs were identified in four patients. The locations of the APs in the remaining three patients were the right posterior and middle septum. All ATAs and APs were successfully ablated. After a median follow-up of 37 (15-72) months, no anterograde conduction over the AP was recorded, new onset of PAF was recorded in three patients, and all of them underwent circumferential pulmonary vein isolation. WPW with concomitant ATA frequently had continuous anterograde conduction over the AP with a rapid ventricular rate. Most WPWs displayed the characteristic of unidirectional anterograde conduction.

Utility of open window mapping using high-density mapping approach in accessory pathways ablation

Abstract Introduction and purpose We sought to described a new protocol of open window mapping (OW) utilizing high-density mapping in accessory pathways (AP) in CARTO® 3 system. This protocol automatically map conventional electrophysiology criteria for AP location, as shorter local EGM AV interval (extended early meets late tool), earliest local activation time (LAT)and annotation at unipolar signal (wavefront annotation). Methods This was a single center, prospective and observational trial of 21 consecutive patients who underwent an AP catheter ablation. Results We included 16 men and 5 women, with a mean age of 32.6±17.9 years. The characteristics of AP, including mapping and ablation were described in Table 1. Twelve AP were of left location and 9 in right location. Mapping was performed in anterograde conduction in 17 patients (80.9%), retrograde in 9 patients (42.9%) and orthodromic tachycardia in 7 patients (33.3%). Mean mapping points were 3205±2034, with 29.2 min±12.5 min of mapping. All 21 patients had a successful ablation after OW mapping and mean radiofrequency time until complete AP elimination was 2.76 s. We present an example of a Left lateral AP OW mapping in antegrade and retrograde conduction in Figure 1, which shows EEML mapping tool, targeting shorter interval EGM AV or VA and color adjust to determine earliest LAT in chamber of exit. Conclusions In our experience, automatically mapping of conventional electrophysiology criteria for AP diagnostic is feasible to localize AP insertion, suggesting an increasing in effectiveness of procedure, and reducing mapping time, ablation time and X-ray exposure time. More studies should be performed to corroborate these conclusions. Funding Acknowledgement Type of funding sources: None.

P34 ASYMPTOMATIC VENTRICULAR PRE–EXCITATION WITH DISAPPEARANCE DURING EXERTION: ALWAYS AN INDEX OF BENIGNITY?

Abstract Introduction The disappearance of pre–excitation at high heart rates points to a low arrhythmic risk: why resort to electrophysiological studies anyway? Clinical Case L.S., a 12–year–old patient, performed an ECG for sports examination with evidence of ventricular pre–excitation from an asymptomatic left lateral accessory route (Fig. A). A 24 h ECG–Holter during training showed the disappearance of the pre–excitation at high frequencies (Fig. B) which is considered a low risk index. The patient underwent a transesophageal electrophysiological study (SETE) during which an effective refractory antegrade period of 228 ms of the pathway was objectified through atrial extrastimuli (*) (Fig. C: drive of atrial stimuli (*) followed by extrastimulus with conduction on an accessory route (E)). In addition, a 1: 1 conduction was observed on the atrial pathway up to at least 270 bpm (222 ms). The antegrade refractory period of the resting path was <250 ms and therefore identified a high–risk condition to be treated with ablation. Discussion The disappearance of pre–excitation at high heart rates is usually considered indicative of an accessory pathway with a long refractory period and therefore at low risk, however it must be sudden. According to European guidelines, the execution of invasive studies in asymptomatic patients who are employed in high–risk jobs or competitive sports has a class I B indication, but in the remaining asymptomatic cases the indication is IIa B. The Holter ECG alone or the stress test, with a careless evaluation of the disappearance of the pre–excitation (sudden vs progressive with minimal residual pre–excitation) would have erroneously led to labeling this accessory pathway at low risk. In the left lateral accessory pathways, with the increase of the HR, there can be a disappearance or pseudo–disappearance of the pre–excitation for anatomical reasons (being further away from the SA node) and for an increase in the AV conduction speed, not therefore for a long refractory period of the pathway. SETE is closer to the atrial side of the left accessory pathway and allows to correctly classify the risk. Conclusion SETE is a low–cost and minimally invasive method that should be considered as an integral part of the study of patients with asymptomatic ventricular pre–excitation even if non–invasive stratification indicates low risk.

Mitral valve perforation after left lateral accessory pathway ablation: a case report

BackgroundRadiofrequency catheter ablation is considered to be a relatively safe procedure. This is an unusual case report in which severe mitral regurgitation was occurred after left lateral accessory pathway radiofrequency catheter ablation.Case presentationA 15-year-old man without structural heart disease was referred for ablation of a left lateral accessory pathway. He was a rugby player who had lived with Wolff–Parkinson–White syndrome since 2017. In 2017, two failed extensive radiofrequency catheter ablations of a left lateral accessory pathway had been performed in another center. In June 2018, he underwent a third radiofrequency catheter ablation of a left lateral accessory pathway using an anterograde transseptal approach with an early recurrence one month later. A successful fourth procedure was performed in August 2018 using a retrograde aortic approach. Three months later, the patient presented to the hospital with atypical chest pain and dyspnea on exertion. Transthoracic echocardiography revealed severe mitral regurgitation caused by a perforation of the posterior leaflet. Given the symptoms and the severity of the mitral valve regurgitation, the decision was taken to proceed with surgical intervention. Posterior mitral leaflet perforation was confirmed intraoperatively. The patient underwent video-assisted mitral valve repair via Minithoracotomy approach.ConclusionThis case demonstrates a very rare complication of Wolff–Parkinson–White radiofrequency ablation.

C60. Management of Symptomatic Wolff-Parkinson-White (WPW) Syndrome: A Case Report

Abstract Background Atrioventricular reentrant tachycardia (AVRT) could be the reentrant tachyarrhythmia that occurs in Wolff-Parkinson-White (WPW) syndrome. In AVRT, the existence of normal AV node and accessory pathway (AP) along with the atria and ventricles establish the electrical circuit that permits impulse re-entry. The incidence of multiple accessory pathways (MAP) is reported 3-15% and incidence of sudden cardiac death (SCD) in WPW syndrome is about 0.25% per year or 3% to 4% over a lifetime. Case Description We presented a case of Wolff-Parkinson-White Syndrome. A 28-year old man was admitted for evaluation of frequent episodes of palpitation. The diagnosis of WPW syndrome was established based on the 12 lead surface electrocardiogram (ECG). Echocardiography showed normal resting echocardiography then we performed electrophysiology study (EPS). We conducted the radiofrequency ablation (RFA) to the accessory pathway (AP). The challenging point of this case was multiple accessory pathways (APs) located at right posteroseptal and left lateral. Discussion Ablation of multiple accessory pathways (MAP) had a longer fluoroscopic time and large number of unsuccessful attempts than those with a single accessory pathway. We performed RFA at right posteroseptal and left lateral accessory pathway. The radiofrequency ablation has successfully eliminated both accessory pathways. In summary, we conclude that anatomical consideration, EP study, and the ablation strategy was important to improve the safety and success rate of RFA procedure.

C60. Management of Symptomatic Wolff-Parkinson-White (WPW) Syndrome: A Case Report

Abstract Background Atrioventricular reentrant tachycardia (AVRT) could be the reentrant tachyarrhythmia that occurs in Wolff-Parkinson-White (WPW) syndrome. In AVRT, the existence of normal AV node and accessory pathway (AP) along with the atria and ventricles establish the electrical circuit that permits impulse re-entry. The incidence of multiple accessory pathways (MAP) is reported 3-15% and incidence of sudden cardiac death (SCD) in WPW syndrome is about 0.25% per year or 3% to 4% over a lifetime. Case Description We presented a case of Wolff-Parkinson-White Syndrome. A 28-year old man was admitted for evaluation of frequent episodes of palpitation. The diagnosis of WPW syndrome was established based on the 12 lead surface electrocardiogram (ECG). Echocardiography showed normal resting echocardiography then we performed electrophysiology study (EPS). We conducted the radiofrequency ablation (RFA) to the accessory pathway (AP). The challenging point of this case was multiple accessory pathways (APs) located at right posteroseptal and left lateral. Discussion Ablation of multiple accessory pathways (MAP) had a longer fluoroscopic time and large number of unsuccessful attempts than those with a single accessory pathway. We performed RFA at right posteroseptal and left lateral accessory pathway. The radiofrequency ablation has successfully eliminated both accessory pathways. In summary, we conclude that anatomical consideration, EP study, and the ablation strategy was important to improve the safety and success rate of RFA procedure.

Left atrial \u0131ntramural hematoma after radiofrequency catheter ablation of left lateral accessory pathway

We report a case of left atrial hematoma after ablation of left lateral concealed accessory pathway. A 46-year-old male patient experienced chest pain after radiofrequency ablation. Transthoracic echocardiography and computed tomography revealed the intramural mass consistent with hematoma in the left atrium. He was hemodynamically stable, and conservative approach was decided. Atrioventricular groove is a vulnerable part of left atrium, and ablation of left free wall accessory pathway may require targeting both atrial and ventricular surfaces of the mitral annulus. Avoidance of forceful catheter manipulation during the electrophysiological procedure is important for prevention of this complication. Optimal periprocedural anticoagulation might reduce the risk of procedure-related thromboembolic complications, but electrophysiologists should always pay attention to an intramural hematoma that may occur after radiofrequency catheter ablation.

QRS alternans during right ventricular pacing while ablating a concealed left sided accessory pathway

A 16-year-old boy was referred for an electrophysiological study for documented regular narrow complex tachycardia. A diagnosis of a concealed left lateral accessory pathway was made with an eccentric atrial activation sequence both during tachycardia and right ventricular (RV) pacing. The pathway was mapped at the left posterior mitral vestibule during RV pacing, performed through the distal tip of the His bundle catheter pushed into right ventricular outflow tract. An unusual response to ventricular stimulation with alternation of QRS complex width and morphology was noted. The possible mechanisms are hereby discussed.

Catheter ablation for atrial fibrillation in very young patients

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Pulmonary vein automaticity is an established trigger of paroxysmal atrial fibrillation (PAF) making pulmonary vein isolation (PVI) the cornerstone for catheter ablation. However, data on triggers of AF and catheter ablation strategy in very young (<30 years old) patients are sparse. Methods and results: Sixteen young patients (mean age 25.2 ± 4.9 years; 75% men) with recurrent drug refractory PAF underwent EP study and ablation at 3 EP centers. None of the patients had structural heart disease or family history of AF. EP study revealed degeneration of induced supraventricular tachycardia (SVT) into AF in 5 patients (n = 5, 31.2%). Induced SVTs were left lateral concealed accessory pathway mediated orthodromic AVRT in two patients, typical AVNRT in two patients, and left superior PV tachycardia in one patient respectively. In patients with induced SVTs, SVT ablation without PVI was performed as an index procedure. Remaining patients underwent second generation cryoballoon (CB-2) based PVI (n = 11, 68.7%). There were no major complications related to ablation procedures. Follow-up was based on outpatient visits including 24-h Holter-ECG at 3, 6 and, 12 months post ablation, or additional Holter-ECG was ordered in case of symptoms suggesting recurrence. Recurrence was defined as any atrial tachyarrhythmia (ATA) episode >30s following a 3-month blanking period. After a median follow-up of 18.3 ± 6.2 months, 13 of 16 (81.2%) patients were free of ATA recurrence. None of the patients belonging to SVT ablation only group experienced ATA recurrence. Three patients with previous CB-2 PVI recurred, one had typical atrial flutter and underwent CTI ablation, remaining 2 patients had AF recurrence and medically followed. Conclusion In a considerable fraction of young adult patients with history of PAF SVTs may be responsible and SVT ablation without PVI may be sufficient as an index procedure. Catheter ablation AF seems to be safe and effective in this population.

Irregular orthodromic atrioventricular reentrant tachycardia using the left lateral accessory pathway due to intermittent mitral isthmus block

Mitral isthmus block during left lateral accessory pathway ablation has been reported in the past. Here, we document for the first time an irregular atrioventricular reciprocating tachycardia due to alternating mitral isthmus block and mitral isthmus delay, resulting in different atrioventricular node conduction times and tachycardia cycle length.

Safety and efficacy of electrophysiological studies and radiofrequency ablation of paroxysmal supraventricular tachycardia

Introduction: Cardiac electrophysiological study (EPS) and radiofrequency ablation (RFA) is an established mode of treatment either as first-line or for drug-refractory arrhythmias. Our center has recently started this service under 2-D mapping outside Kathmandu valley
 Objective: The aim was to evaluate the safety and efficacy of EPS and RFA for paroxysmal supraventricular tachycardias (PSVT).
 Methodology: This is an observational prospective study carried out in the Cardiac Unit of Nobel medical college, Biratnagar, Nepal. All cases diagnosed to have PSVT based on electrocardiogram or Holter recordingfromAugust 2018 and May2019wereincluded in the study. Data on clinical profile and findings of EPS were recorded. Fifty-nine cases were chosen for safety and efficacy analysis, using SPSS statistical software version 19.
 Results: There were 59 patients, 28(47.5%) males, and 31(52.5%) females. The mean age was 38.2 ± 15.9 years. Fifty-three patients underwent RFA while 6 patients underwent only EPS. In the Atrioventricular nodal reentry tachycardia (AVNRT) group, there was female dominance (P=0.2) while in Atrioventricular reentry tachycardia (AVRT) group, there was no significant gender difference (p=0.4). Left-sided pathway (68%) was more common in the AVRT group. Among the left accessory pathway (AP), left lateral AP (44%) was more common. No major complications including death were noted. Two cases of successful ablation relapsed in one month follow up.
 Conclusions: Early results of this small study in patients with PSVT confirm the efficacy and safety of RFA in newly established electrophysiology (EP) laboratory.

High-density Grid Use for Left Lateral Accessory Pathway.

High-density Grid Use for Left Lateral Accessory Pathway.

Development and evaluation of 12-lead electrocardiogram in the left free wall of accessory pathway localization in patients with typical Wolff-Parkinson-White syndrome

Objectives: This study was designed to characterize 12-lead electrocardiogram (ECG) for localization of the left free wall lateral accessory pathway (AP) in patients with typical Wolff-Parkinson-White (WPW) syndrome, to develop a new algorithm ECG for localizing APs, and to test the accuracy of the algorithm prospectively.
 Method: We studied 129 patients; 84 patients had typical WPW syndrome with single anterograde AP identified by successful radiofrequency catheter ablation (RFCA), and were enrolled to build a new ECG algorithm for localizing left free wall APs. Then, the algorithm was tested prospectively in 45 patients and compared with the location of APs successfully ablated by RFCA.
 Results: We found that the 12-lead ECG parameters in typical WPW syndrome, such as delta wave polarity in V1, R/S ratio in V1, transition of the QRS complex, and delta wave polarity in inferior, lead to diagnosis and localization of APs, with highest accuracy predicted from 74.5%-100%, and for development of a new ECG algorithm. From the 45 patients who were prospectively evaluated by the newly derived algorithm for the left free wall pathways, the sensitivity and specificity was high (from 75-100%).
 Conclusion: The 12-lead ECG parameters in typical WPW syndrome are closely related to left free wall AP localization and can be used to develop a new ECG algorithm by the parameters above. Moreover, the new ECG algorithm can predict the location of APs with high accuracy.

Comparison of the Accuracy of Three Algorithms in Predicting Accessory Pathways among Adult Wolff-Parkinson-White (WPW) Syndrome Patients in our Population

Background: after the introduction of catheter ablation of atrioventricular accessory pathways (APs) in Wolff-Parkinson-White (WPW) syndrome, to facilitate planned ablation and minimize catheter-related injury, predicting the AP was required. Localization of APs can be anywhere around the atrioventricular (AV) annuli, left- or right-sided, or within the septum or a rare possibility of Mahaim fibers. Objective: to compare between three algorithms in their accuracy in predicting the exact site of accessory pathway. Patients and Methods: one hundred patients with manifest pre-excitation who underwent electrophysiological study (EPS) and successful ablation of accessory pathway who were subjected to history taking, complete physical examination stressing on 12-lead of pre-excited electrocardiogram (ECG). Results: the distributions of the accessory pathway with left lateral accessory pathway being the most prevalent (27%) while the postero-lateral being the least prevalent one (2%) and that Right-sided accessory pathway was most frequently predicted by Arruda algorithm in 31% of patients and least frequently predicted by D’Avila in 17% of patients while its actually present in 23% of patients according to the EP study, Left-sided accessory pathway was most frequently predicted by D’Avila (61%) and least frequently predicted by Arruda (49%) whereas it was truly present in 51% of patients according to EP study. Mid and antero-septal accessory pathways were most frequently predicted by Chiang and least frequently predicted by Arruda while it was present in 26% of cases proved by EP study. In all algorithms, 72 % of predictions were correct for Chiang, 81 % for D’Avila, and 71 % for Arruda and the percentage of predictive accuracy of all algorithms did not differ between the algorithms (p=1.000; p=0.076; p=0.064, respectively) The best algorithm for prediction of right-sided and left-sided accessory pathways was D’Avila (p<0.001). The best algorithm that is particularly useful in predicting antero-septal and mid-septal accessory pathways was Chiang (p<0.001). Conclusion: prior knowledge of the AP location allows better planning, faster and safer procedure, as well as decreased exposure to ionizing radiation and unnecessary punctures. In all algorithms, 72% of predictions were correct for Chiang, 81% for D'Avila, and 71% for Arruda and the percentage of predictive accuracy of all algorithms did not differ between the algorithms (p=1.000; p=0.076; p=0.064, respectively). The best algorithm for prediction of right-sided and left-sided accessory pathways was D'Avila (p<0.001). The best algorithm that is particularly useful in predicting anteroseptal and mid-septal accessory pathways was Chiang (p<0.001).

Comparison of the Accuracy of Three Algorithms in Predicting Accessory Pathways among Adult Wolff-Parkinson-White (WPW) Syndrome Patients in our Population

Background: after the introduction of catheter ablation of atrioventricular accessory pathways (APs) in Wolff-Parkinson-White (WPW) syndrome, to facilitate planned ablation and minimize catheter-related injury, predicting the AP was required. Localization of APs can be anywhere around the atrioventricular (AV) annuli, left- or right-sided, or within the septum or a rare possibility of Mahaim fibers. Objective: to compare between three algorithms in their accuracy in predicting the exact site of accessory pathway. Patients and Methods: one hundred patients with manifest pre-excitation who underwent electrophysiological study (EPS) and successful ablation of accessory pathway who were subjected to history taking, complete physical examination stressing on 12-lead of pre-excited electrocardiogram (ECG). Results: the distributions of the accessory pathway with left lateral accessory pathway being the most prevalent (27%) while the postero-lateral being the least prevalent one (2%) and that Right-sided accessory pathway was most frequently predicted by Arruda algorithm in 31% of patients and least frequently predicted by D’Avila in 17% of patients while its actually present in 23% of patients according to the EP study, Left-sided accessory pathway was most frequently predicted by D’Avila (61%) and least frequently predicted by Arruda (49%) whereas it was truly present in 51% of patients according to EP study. Mid and antero-septal accessory pathways were most frequently predicted by Chiang and least frequently predicted by Arruda while it was present in 26% of cases proved by EP study. In all algorithms, 72 % of predictions were correct for Chiang, 81 % for D’Avila, and 71 % for Arruda and the percentage of predictive accuracy of all algorithms did not differ between the algorithms (p=1.000; p=0.076; p=0.064, respectively) The best algorithm for prediction of right-sided and left-sided accessory pathways was D’Avila (p<0.001). The best algorithm that is particularly useful in predicting antero-septal and mid-septal accessory pathways was Chiang (p<0.001). Conclusion: prior knowledge of the AP location allows better planning, faster and safer procedure, as well as decreased exposure to ionizing radiation and unnecessary punctures. In all algorithms, 72% of predictions were correct for Chiang, 81% for D'Avila, and 71% for Arruda and the percentage of predictive accuracy of all algorithms did not differ between the algorithms (p=1.000; p=0.076; p=0.064, respectively). The best algorithm for prediction of right-sided and left-sided accessory pathways was D'Avila (p<0.001). The best algorithm that is particularly useful in predicting anteroseptal and mid-septal accessory pathways was Chiang (p<0.001).

High-resolution mapping and ablation of recurrent left lateral accessory pathway conduction

Proper localization of the anatomical target during ablation of the accessory pathways (AP) and the ability to detect clear AP potentials on the ablation catheter are crucial for successful AP ablation. We report a case of recurring AP conduction that was finally eliminated using a novel ablation catheter equipped with high-resolution mini-electrodes. Smaller and closer electrodes result in high mapping resolution with less signal averaging and cancellation effects. Owing to improved sensitivity, the new catheter seems effective in detecting fragmented and high frequency signals, thus allowing more effective radiofrequency application and improving ablation success.