Maximal Pre-Excitation Based Algorithm for Localization of Manifest Accessory Pathways in Adults

Is this an anteroseptal accessory pathway?

The ECG of a patient during sinus rhythm shows preexcited QRS pattern, with rS pattern in lead V1, transition in lead V2, and positive inferior leads. Following the stepwise algorithms, the location of accessory pathway (AP) was identified at anteroseptal region. However, the precordial transition in lead V2 indicates mid-septal or posteroseptal AP. The mismatch suggested multiple APs and 5 APs were identified by electrophysiologic study. This case highlights the importance of detailed analysis of ECG in order to achieve adequate ablation.

Landiolol, an intravenous β1-selective blocker, is useful for dissociating a fusion of atrial activation via accessory pathway and atrioventricular node

Introduction

During ventricular pacing, a fusion of atrial activation may occur owing to the simultaneous retrograde conduction of the atrioventricular (AV) node and accessory pathway (AP), potentially leading to an inaccurate mapping of the atrial AP insertion site.

Objective

We tested the hypothesis that landiolol, an ultra-short-acting intravenous β1-blocker, could dissociate a fusion of atrial activation.

Methods

We conducted a prospective before-and-after study to investigate the effect of landiolol on retrograde conduction via the AV node and AP. We enrolled 21 consecutive patients with orthodromic AV reciprocating tachycardia who underwent electrophysiological studies at our hospital between January 1, 2018, and August 31, 2020.

Results

Six patients exhibited a fusion of atrial activation. After landiolol administration (10 μg/kg/min), the effective refractory period was unchanged in AP (280 [240-290] ms vs. 280 [245-295] ms, p = .91), whereas that of the AV node was prolonged (275 [215-380] ms vs. 332 [278-445] ms, p = .03). The Wenckebach pacing rate via retrograde AV node decreased after landiolol administration (180 [140-200] beats per minute [bpm] vs. 140 [120-180] bpm, p = .02). Thus, landiolol decreased the minimum ventricular pacing rate required to dissociate a fusion of atrial activation (180 [160-200] bpm vs. 140 [128-155] bpm, p = .007). Radiofrequency catheter ablation under landiolol administration successfully eliminated AP in all patients during ventricular pacing without complications or recurrence.

Conclusion

Landiolol inhibited the AV node without affecting the AP and helped dissociate a fusion of atrial activation at a lower ventricular pacing rate.

Electrocardiographic patterns of ventricular pre-excitation in dogs with right-sided accessory pathways

INTRODUCTION

The aim of the study was to describe the electrocardiographic features of ventricular pre-excitation (VPE) patterns characterized by the presence of delta (δ) wave, short P-δQRS interval, wide δQRS complexes in dogs with right-sided accessory pathways.

ANIMALS, MATERIALS AND METHODS

Twenty-six dogs with a confirmed accessory pathways (AP) via electrophysiological mapping were included. All dogs underwent a complete physical examination, 12-lead ECG, thoracic radiography, echocardiographic examination and electrophysiologic mapping. The AP were located in the following regions: right anterior, right posteroseptal, right posterior. The following parameters were determined: P-δQRS interval, δQRS duration, δQRS axis, δQRS morphology, δ-wave polarity, Q-wave, R-wave, R'-wave, S-wave amplitude, and R/S ratio.

RESULTS

In lead II, the median δQRS complex duration was 82.4 (IQR 7.2) and the median P-δQRS interval duration was 54.6 (IQR 4.2) msec. The median δQRS complex axis in the frontal plane was: + 68° (IQR 52.5) for right anterior APs, - 24 ° (IQR 24) for right postero-septal APs, - 43.5 ° (IQR 27.25) for right posterior APs (P = 0.007). In lead II, the polarity of the δ wave was positive in 5/5 right anterior APs and negative in 7/11 postero-septal APs and 8/10 in right posterior APs. In precordial leads of all dogs, R/S was ≤ 1 in V1 and > 1 in all leads from V2 to V6.

CONCLUSION

Surface electrocardiogram can be used to distinguish right anterior APs from right posterior and right postero-septal ahead of an invasive electrophysiological study.

Unusual QRS complexes associated with the simultaneous presence of a right-sided accessory pathway, fasciculoventricular pathway, and incomplete right bundle branch block

A 52-year-old man presented with delta waves on a body surface electrocardiogram, which suggested the presence of a right-sided accessory pathway (AP). Patients with right-sided APs generally have an rS pattern in leads V1-2, while he had an rS in lead V1 but an Rs in lead V2, which could not rule out the possibility of the presence of a septal AP or fasciculoventricular pathway (FVP). On the other hand, patients with septal APs or FVPs generally have a QS pattern in lead V1 instead of an rS pattern. An electrophysiological study demonstrated that the simultaneous presence of a right-sided posterolateral AP and FVP with incomplete right bundle branch block (ICRBBB) generated those unusual QRS complexes. The FVP arose distal to the site with ICRBBB, and the ICRBBB delayed the initiation of the FVP conduction. The delayed QS and Rs waves in leads V1-2 generated by the FVP conduction with ICRBBB appeared to produce rS and Rs patterns in leads V1-2, respectively. A radiofrequency application along the posterolateral tricuspid annulus eliminated the right-sided AP conduction. If the localization of APs based on the QRS morphology is difficult, multiple APs or an FVP with a conduction system disturbance should be noted.

Learning objective

Patients with right-sided posterolateral accessory pathways (APs) generally have an rS pattern in lead V2, while patients with fasciculoventricular pathways (FVPs) generally have a QS pattern in lead V1. The present case with a suspected right-sided posterolateral AP had unusual QRS complexes, an rS in lead V1, Rs in lead V2, and monophasic R in leads V3-6, which were associated with the simultaneous presence of a right-sided posterolateral AP, FVP, and incomplete right bundle branch block.

A Single-lead ECG algorithm to differentiate right from left manifest accessory pathways: A reappraisal of the P-Delta interval

INTRODUCTION

Despite numerous ECG algorithms being developed to localize the site of manifest accessory pathways (AP), they often require stepwise multiple-lead analysis with variable accuracy, limitations, and reproducibility. The study aimed to develop a single-lead ECG algorithm incorporating the P-Delta interval (PDI) as an adjunct criterion to discriminate between right and left manifest AP.

METHODS

Consecutive WPW patients undergoing electrophysiological study (EPS) were retrospectively recruited and split into a derivation and validation group (1:1 ratio). Sinus rhythm ECG analysis in lead V1 was performed by three independent investigators blinded to the EPS results. Conventional ECG parameters and PDI were assessed through the global cohort.

RESULTS

A total of 140 WPW patients were included (70 for each group). A score-based, single-lead ECG algorithm was developed through derivation analysis incorporating the PDI, R/S ratio, and QRS onset polarity in lead V1. The validation group analysis confirmed the proposed algorithm's high accuracy (95%), which was superior to the previous ones in predicting the AP side (p < 0.05). A score of ≤+1 was 96.5% accurate in predicting right AP while a score of ≥+2 was 92.5% accurate in predicting left AP. The new algorithm maintained optimal performance in specific subgroups of the global cohort showing an accuracy rate of 90%, 92%, and 96% in minimal pre-excitation, posteroseptal AP, and pediatric patients, respectively.

CONCLUSIONS

A novel single-lead ECG algorithm incorporating the PDI interval with previous conventional criteria showed high accuracy in differentiating right from left manifest AP comprising pediatric and minimal pre-excitation subgroups in the current study.

EASY-WPW: a novel ECG-algorithm for easy and reliable localization of manifest accessory pathways in children and adults

AIMS

Accessory pathway (AP) ablation is a standard procedure for the treatment of Wolff-Parkinson-White syndrome (WPW). Twelve-lead electrocardiogram (ECG)-based delta wave analysis is essential for predicting ablation sites. Previous algorithms have shown to be complex, time-consuming, and unprecise. We aimed to retrospectively develop and prospectively validate a new, simple ECG-based algorithm considering the patients' heart axis allowing for exact localization of APs in patients undergoing ablation for WPW.

METHODS AND RESULTS

Our multicentre study included 211 patients undergoing ablation of a single manifest AP due to WPW between 2013 and 2021. The algorithm was developed retrospectively and validated prospectively by comparing its efficacy to two established ones (Pambrun and Arruda). All patients (32 ± 19 years old, 47% female) underwent successful pathway ablation. Prediction of AP-localization was correct in 197 patients (93%) (sensitivity 92%, specificity 99%, PPV 96%, and NPV 99%). Our algorithm was particularly useful in correctly localizing antero-septal/-lateral (sensitivity and specificity 100%) and posteroseptal (sensitivity 98%, specificity 92%) AP in proximity to the tricuspid valve. The accuracy of EASY-WPW was superior compared to the Pambrun (93% vs. 84%, P = 0.003*) and the Arruda algorithm (94% vs. 75%, P < 0.001*). A subgroup analysis of children (n = 58, 12 ± 4 years old, 55% female) revealed superiority to the Arruda algorithm (P < 0.001*). The reproducibility of our algorithm was excellent (ϰ>0.8; P < 0.001*).

CONCLUSION

The novel EASY-WPW algorithm provides reliable and accurate pre-interventional ablation site determination in WPW patients. Only two steps are necessary to locate left-sided AP, and three steps to determine right-sided AP.

Preprocedural Discrimination of Posteroseptal Accessory Pathways Ablated from the Right Endocardium from Those Requiring a Left-sided or Epicardial Coronary Venous Approach

The success of radiofrequency catheter ablation of the accessory pathway (AP) depends on the accurate localisation of the bypass tract. In that respect, posteroseptal or inferior paraseptal APs often pose a diagnostic challenge because of the complex anatomy at the crux of the four cardiac chambers. Considering the differences in procedure risks and success rate depending on the need for a left-sided approach or a coronary sinus ablation, an accurate anticipation of the precise location of inferior paraseptal APs is critical to inform the consent process and guide the initial mapping strategy. Here, the preprocedural clues to discriminate APs that can be ablated from the right atrium, from those requiring a left-sided or epicardial coronary venous approach, are reviewed. Both manifest and concealed APs will be considered and, following the diagnostic process made by the operator before interpretation of the intra-cardiac signals, each of the following aspects will be addressed: clinical context and initial probability; and 12-lead ECG analysis during baseline ECG with manifest AP, maximal preexcitation, and orthodromic reciprocating tachycardia.

Is there a need for a novel algorithm for accessory pathways localization?

Wolff Parkinson White Syndrome (WPW) affects between 0.1% and 0.2% of the population, causes morbidity due to supraventricular tachycardia (SVT) and can lead to sudden cardiac arrest [1-3]. This article is protected by copyright. All rights reserved.

V1r + DIIq is a novel and accurate criterion to predict right vs. left paraseptal accessory pathways

PURPOSE

The correct estimation of accessory pathway (AP) localization from surface ECG is critical before the procedure. Our study aimed to detect the predictive value of the V1r + DIIq criterion for differentiating right- from left-sided paraseptal APs.

METHODS

We retrospectively included 58 patients with (Wolff-Parkinson-White) WPW syndrome and paraseptal APs who underwent successful catheter ablation (37 male, 21 female; mean age 34.4 ± 13.6 years). The V1r + DIIq criterion was calculated using the following formula: V1r + DIIq (mV) = initial r wave amplitude in V1 + q wave amplitude in DII. The combined criterion included V1r + DIIq <2.05 mV and/or no initial r wave in V1.

RESULTS

Right-sided paraseptal APs were detected in 36 patients (62.1%), left-sided paraseptal APs were detected in 21 patients (36.2%), and AP from CS was detected in 1 patient (1.7%). The initial r wave amplitude in V1 (mV), q wave amplitude in DII (mV) and V1r + DIIq criterion (mV) were lower in patients with right-sided paraseptal APs (p < 0.001). The percentage of patients with no initial r wave in V1 (36.1% vs. 0%) and those meeting the combined criterion (91.7% vs. 4.5%) were increased in patients with right-sided paraseptal APs. The cutoff value of the V1r + DIIq criterion obtained by ROC curve analysis was 2.05 mV for predicting right-sided paraseptal APs (sensitivity: 86.1%, specificity: 95.5%). The area under the curve (AUC) was 0.943 (95% CI = 0.881-1.000) (p < 0.001). The sensitivity and specificity values were 36.1% and 100%, respectively, for the no initial r wave criterion and 91.7% and 95.5%, respectively, for the combined criterion.

CONCLUSION

The V1r + DIIq criterion and the combined criterion represent novel and simple electrocardiographic criteria for accurately differentiating right- from left-sided paraseptal APs. This simple ECG measurement can improve the accuracy of detection of paraseptal AP localization and could be beneficial for decreasing ablation duration and radiation exposure.

Merged two-way mapping technique: an alternative 3D electroanatomical mapping approach to guide challenging ablation procedures of accessory pathways with bidirectional conduction properties

BACKGROUND

Catheter ablation of accessory pathways (AP) with bidirectional conduction may be challenging due to issues related to anatomical course or location.

OBJECTIVE

We describe an alternative electro-anatomical mapping technique which aims at depicting the entire anatomic course of the AP from the atrial toward the ventricular insertion in order to guide catheter ablation.

METHODS

Twenty consecutive patients with confirmed bidirectional AP conduction and at least one previous ablation procedure or para-Hisian location were included. 3-D electro-anatomical mapping was used to depict the merged 10-ms isochrone area of maximum early activation of both the ventricular and atrial signals during sinus rhythm and ventricular pacing/orthodromic tachycardia, respectively. Catheter ablation was performed within the depicted earliest isochrone area.

RESULTS

Acute bidirectional AP conduction block was achieved in all patients 4.2 ± 1.7 s after the first radiofrequency energy pulse was delivered, without reconnection during a 30 ± 10 min post-ablation observation time. No procedural complications were seen. After a mean follow-up period of 9 ± 7 months (range 3 to 16), no recurrences were documented.

CONCLUSION

This merged two-way mapping technique is a safe, efficient, and effective technique for ablation of APs with bidirectional conduction.

A case of transient ventricular pre-excitation associated with takotsubo cardiomyopathy

A 75-year-old woman, who had never exhibited a delta wave before, was diagnosed with sigmoid colon cancer and underwent surgical operation. Takotsubo cardiomyopathy (TC) occurred shortly after the operation. About 2 weeks following the onset of TC, a 12‑lead electrocardiogram revealed a delta wave that was present for 50 days, and the patient was diagnosed with transient ventricular pre-excitation. The delta wave disappeared prior to patient's discharge and was never observed thereafter. This transient appearance of a delta wave may be related to a pathological modulation of the autonomic nervous system during the acute phase of TC.

Algorithms to Identify Accessory Pathways' Location on the 12-Lead Electrocardiogram

The ability to estimate accessory pathway (AP) position enables pre-procedural planning, reduces mapping times, and improves risk estimates as part of the patient consent process. In this article, the nomenclature and important concepts of AP localization algorithms are outlined. An overview of three prominent algorithms is then provided. Each represents an era of invasive treatment of APs: surgical therapy, endocardial ablation, and contemporary electroanatomic mapping. In this manner, the premises, pitfalls, and evolution of AP localization algorithms are illustrated. In addition, the pertinent features of their work are distilled in a simplified topographic algorithm with the interventional electrophysiologist in mind.

What Have We Learned from the European Society of Cardiology 2019 Guidelines on Supraventricular Tachycardia

Supraventricular tachycardias (SVTs) are common arrhythmic conditions in clinical practice. Increased knowledge and experience on SVTs and some unclear situations in clinical practice led the European Society of Cardiology (ESC) team to write a new guideline. In this review, we touch upon the important points in the new ESC 2019 SVT guidelines and present changing approaches and suggestions. By providing a general review on SVTs, we also mention the basic mechanism, epidemiology, and clinical presentation of SVTs, approaching narrow and wide QRS tachycardias, SVTs in special patient groups, and treatment of SVTs.