Validation of qrs-polarity algorithm with special emphasis in parahisian pathways / Validación del algoritmo de la polaridad del qrs con especial énfasis en vías parahisianas

Abstract Background: 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. Purpose: 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. Methods: 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. Results: 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. Conclusion: 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.

Resumen Antecedentes: En 1996 Iturralde y colaboradores publicaron un algoritmo basado en la polaridad del QRS para determinar la ubicación de las vías accesorias (VA), este algoritmo fue desarrollado antes de la práctica masiva de la electrofisiología invasiva. Objetivo: Validar el algoritmo de la polaridad del QRS en una cohorte moderna de sujetos sometidos a ablación con catéter por radiofrecuencia (ACRF). Nuestro objetivo fue determinar su precisión global y su precisión para las VA parahisianas. Métodos: Realizamos un análisis retrospectivo de pacientes con síndrome de Wolff-Parkinson-White (WPW) a los que se les realizó estudio electrofisiológico (EEF) y ACRF. Empleamos el algoritmo de la polaridad del QRS para predecir la ubicación anatómica de la VA y comparamos este resultado con la ubicación anatómica real determinada en el EEF. Para determinar la precisión se utilizaron el coeficiente kappa de Cohen (k) y el coeficiente de correlación de Pearson. Resultados: Se incluyeron un total de 364 pacientes (edad media 30 años, 57 % varones). La puntuación k global fue de 0,78 y el coeficiente de Pearson de 0,90. También se evaluó la precisión para cada zona, la mejor correlación fue para las VA laterales izquierdas (k de 0.97). Hubo 26 pacientes con VA parahisianas, que mostraron una gran variabilidad en las características del ECG. Empleando el algoritmo de la polaridad del QRS, el 34,6 % de los pacientes tenía una ubicación anatómica correcta, el 42,3 % tenía una ubicación adyacente y solo el 23 % una ubicación incorrecta. Conclusión: El algoritmo de la polaridad del QRS tiene una buena precisión global; su precisión es alta, especialmente para VA lateral izquierdo. Este algoritmo también es útil para la VA parahisiana.

Duración de la onda P en las 12 derivaciones del electrocardiograma y su relación con el tiempo de conducción interauricular en pacientes con taquicardias paroxísticas supraventriculares / P wave duration in the 12 leads of the electrocardiogram and its relationship with interatrial conduction time in patients with paroxysmal supraventricular tachycardias

RESUMEN Introducción: Existen algunos estudios que relacionan parámetros de la onda P con diferentes tiempos de conducción auricular, pero no se han realizado teniendo en cuenta a cada derivación del electrocardiograma. Objetivo: Determinar la duración de la onda P (Pdur) en las 12 derivaciones y relacionarlas con el tiempo de conducción interauricular. Método: Estudio de corte transversal en 153 pacientes adultos con diagnóstico confirmado de taquicardia por reentrada intranodal (TRIN) o vías accesorias mediante estudio electrofisiológico invasivo. Resultados: Al comparar la Pdur entre sustratos arrítmicos por cada derivación, no existieron diferencias significativas, excepto en V6. En las derivaciones DII, DIII, aVR, aVF, V1 y de V3-V6 la Pdur se correlacionó con el tiempo de conducción interauricular en ambos sustratos arrítmicos. En el análisis multivariado, la Pdur constituyó un predictor independiente de tiempos de conducción interauricular ≥ 95 percentil, en las derivaciones de cara inferior y en V3, V5 y V6. Se observaron altos valores del área bajo la curva de la Característica Operativa del Receptor en las derivaciones DII (0,950; p<0,001), DIII (0,850; p<0,001) y V5 (0,891; p<0,001). Conclusiones: No existen diferencias por derivación en la Pdur al comparar casos con TRIN y vías accesorias, excepto en V6. La mayoría de las derivaciones se correlacionaron con el tiempo de conducción interauricular. La Pdur fue un predictor independiente de tiempos de conducción interauricular ≥ 95 percentil. La derivación DII presenta la mayor capacidad discriminativa para encontrar valores prolongados del tiempo de conducción interauricular.

ABSTRACT Introduction: Although some studies relate P wave parameters to different atrial conduction times, they do not consider each electrocardiogram lead separately. Objective: To determine the duration of P wave (Pdur) in the 12 leads of the electrocardiogram and relate it to the interatrial conduction time. Method: We conducted a cross-sectional study in 153 adult patients with confirmed diagnosis of atrioventricular nodal reentry tachycardia (AVNRT) or accessory pathways by invasive electrophysiological study. Results: When comparing the Pdur between arrhythmic substrates by each lead, no significant differences were found, except for V6. In leads II, III, aVR, aVF, V1 and V3-V6, Pdur was correlated with the interatrial conduction time in both arrhythmic substrates. In our multivariate analysis, the Pdur was an independent predictor of interatrial conduction times ≥ 95 percentile in inferior wall leads and in V3, V5 and V6. High values of the area under the receiver operating characteristic curve were observed in II (0.950; p<0.001), III (0.850; p<0.001) and V5 (0.891; p<0.001) leads. Conclusions: The Pdur showed no difference by leads when comparing cases with AVNRT and accessory pathways, except for V6. Most of the leads were correlated with the interatrial conduction time; Pdur was an independent predictor of interatrial conduction times ≥ 95 percentile. Lead II has the greatest discriminatory ability to find prolonged values of interatrial conduction time.

Analysis of clinical and electrophysiological characteristics of children with Wolff-Parkinson-White syndrome or ventricular pre-excitation / 中华实用儿科临床杂志

Objective@#To summarize the clinical and electrophysiological characteristics of children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.@*Methods@#One hundred and seventy-nine consecutive children with Wolff-Parkinson-White syndrome or ventricular pre-excitation who were hospitalized at Beijing Anzhen Hospital Affiliated to Capital Medical University and planned to accept radiofrequency ablations were selected.Electrocardiogram and echocardiography were completed and detailed clinical data were collected before ablations.Anterograde refractory period of accessory pathways (ERPAPA) and retrograde ventriculoatrial conduction were measured during electrophysiology studies.The clinical and electrophysiological characteristics of these children were analyzed.@*Results@#The ratio of left-sided to right-sided accessory pathways was 1.001.93(61 cases vs.118 cases). Six out of 61 patients with left-sided accessory pathways were verified by electrophysiology study.There was no statistical difference of P-R interval and QRS duration between patients with right-sided and left-sided accessory pathways(all P>0.05). Twelve patients were combined with congenital heart diseases.Fourteen patients with right-sided accessory pathways were of ventricular pre-excitation induced dilated cardiomyopathy.ERPAPA was measured successfully in 110 patients, ERPAPA less than 250 ms accounted for 32.7%(36/110 cases). Six children with two pathways were recognized.Antidromic atrioventricular reentrant tachycardia was induced in 3 children.One child had slow conduction pathway localized in right-sided septum.@*Conclusions@#Right-sided overt accessory pathways are more common in children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.Organic heart diseases are not uncommon.Besides congenital heart disease, a small proportion of patients with right overt accessory pathways may develop ventricular pre-excitatory induced dilated cardiomyopathy resulting from ventricular wall dyskinesia.Most of the decremental retrograde ventriculoatrial conduction is the characteristic of ventricular muscles rather than the accessory pathways in nature.Two pathways are not uncommon in children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.Before finishing radiofrequency ablation, the anterograde and retrograde function of the accessory pathway should be evaluated in detail again because it is easy to neglect the existence of another accessory pathway.

Características electrocardiográficas de vías fascículo-ventriculares en pediatría: estudio comparativo con las vías accesorias anteroseptalesderechas / Electrocardiographic characteristics of fasciculo-ventricular accessory pathways in children: A comparative study with right anteroseptal accessory pathways

Resumen Objetivos: Las vías accesorias (VAc) fascículo-ventriculares (FV) tienen una localización anatómica similar a las VAcanteroseptales derechas (ASD) y comparten características electrocardiográficas. El objetivo es comparar características electrocardiográficas de las VAC FV con las de las ASD en pediatría. Métodos: Se incluyeron pacientes con preexcitación manifiesta sometidos a estudio electrofisiológico. Las VAc FV se definieron por un intervalo HV ≤ 32ms y un alargamiento del AH sin modificación del HV, del grado o patrón de preexcitación ventricular durante la estimulación auricular. Tres observadores independientes y ciegos analizaron los ECG en cada grupo. Resultados: De 288 pacientes, 15 (5.2%) presentaban VAC FV y 14 VAC ASD (4.9%). El intervalo PR fue más largo en las VAc FV que en las ASD (113 ± 21 vs. 86 ± 13 ms respectivamente; p = < 0.001) y la duración del QRS fue menor (95 ± 12 vs. 137 ± 24 ms respectivamente; p = < 0.001). El ECG de las VAc FV presentó una deflexión rápida de baja amplitud previa al inicio del QRS en 13 de 15 pacientes (87%) y en 2 con VAc AV ASD (14%); (p = 0.003). Conclusiones: El intervalo PR fue más largo y el complejo QRS más angosto en la VAC FV respecto de las ASD. La presencia de una deflexión rápida de baja amplitud previa al inicio del QRS permitiría diferenciarlas de las aurículo-ventriculares ASD de manera no invasiva.

Abstract Objectives: Fasciculo-ventricular (FV) accessory pathways (AP's) and right anteroseptal (RAS) AP's share similar anatomic locations and electrocardiographic characteristics. The objective of this article is to compare these features in children. Methods: All patients with manifest pre-excitation who underwent an electrophysiological study were included. Fasciculo-ventricular AP's were defined by the presence of an HV inter- val ≤ 32 ms and a prolongation of the AH without changes in the HV interval, or the level of pre-excitation during atrial pacing. Three independent and blind observers analysed the ECG's in both groups. Results: Out of 288 patients, 15 (5.2%) had FV AP's and 14 (4.9%) right AS AP's. The PR interval was longer in FV AP's than in RAS (113 ± 21 vs 86 ± 13 ms respectively; P < .001) and the QRS was narrower (95 ± 12 vs 137 ± 24 ms respectively; P < .001). The ECG in patients with FV AP's showed a rapid low amplitude deflection at the begining of the QRS in 13 out of 15 patients (87%) and in 2 (14%) the RAS AP group (P = .003). Conclusions: The PR interval was longer and the QRS complex was narrower in patients with FV AP's. The presence of a rapid low amplitude deflection at the beginning of the QRS complex would allow to differentiate them from RAS AP's non-invasively.

Vias fascículo ventriculares: una rareza electrofisiológica / Ventricular fascicle pathways: an electrophysiological rarity / Vias fascículo-ventriculares: uma raridade eletrofisiológica

Las vias fascículo ventriculares (FV) sustentan una forma rara de preexcitation en la que la morfologia ECG recuerda a la de las vias paraseptales superiores, pero no participan en mecanismos de taquicardia ni requieren tratamiento específico. Algumas diferencias electrocardiográficas, la respuesta a la adenosina intravenosa y, sobre todo el estudio electrofisiológico sientam el diagnóstico diferencial. Se presentan los dos casos con vias FV de una serie consectiva de 62 pacientes con vias accesorias patentes remitidos a nuestro laboratorio para ablación con radiofrecuencia. En uno no se indujeron arritmias y en otro se indujo una taquicardia por reentrada nodal, que se sometió a ablación con êxito y que permitió el diagnóstico de inserción infrahisiana de la via accessoria FC.

Ventricular fascicle connections are an unusual form of pre-excitation. The 12-lead surface ECG during sinus rhythm is similar to the ECG of patients with anteroseptal and midseptal bypass tracts. These fibers do not participate in the tachycardia circuit or need any treatment. Electrocardiographic differences, the response to adenosine and particularly, the electrophysiologicstudy will guide to the correct diagnosis. We present two cases of ventricular fascicle connections in a consecutive series of 62 patients with accessory pathways referred to our service for evaluation and ablation. In one patient, no arrhythmias were induced, and in another patient an atrio-ventricular reentrant nodal tachycardia was induced, which was successfully ablated. The study also revealed theinfra-Hisian insertion of the ventricular fascicle connection.

As vias fascículo-ventriculares (FV) sustentam uma forma rara de pré-excitação em que a morfologia ECG recorda a das vias paraseptais superiores, mas não participam dos mecanismos de taquicardia nem requerem tratamento específico. Algumas diferenças eletrocardiográficas, a resposta à adenosina intravenosa e, sobretudo, o estudo eletrofisiológico estabelecem o diagnóstico diferencial. Apresentam-se os dois casos com vias FV de uma série consecutiva de 62 pacientes com viasacessórias patentes encaminhados ao nosso laboratório para ablação com radiofrequência. Em um não foram induzidas arritmias e no outro foi induzida uma taquicardia por reentrada nodal, que foi submetida à ablação com sucesso e que permitiu o diagnóstico de inserção infra-hissiana da via acessória FV.

Electrophysiological effects of ibutilide on normal cardiac conduction system and accessory pathways / 第二军医大学学报

Objective: To observe the electrophysiological effects of ibutilide on the normal cardiac conduction system and accessory pathways (AP) of patients with accessory pathways mediated reentrant tachycardia (AVRT) and to assess the safety of ibutilide in electrophysiology study (EPS) and radiofrequency catheter ablation (RFCA). Methods: Twenty-one patients with AVRT undergoing EPS received intravenous ibutilide (1 mg). Electrophysiological parameters, including P-A interval, A-H interval, H-V interval, QRS complex width, QT interval, paced QT interval, right atrial effective refractory period (RA ERP), right ventricular ERP (RV ERP)q atrioventricular node ERP (AVN ERP), AVN block cycle length (AVN BCD, antegrade AP ERP and retrograde AP ERP 9 were observed before and instantly, 15 min, and 30 min after injection of ibutilide. Results: There was no statistical difference in the P-A interval, A-H interval, H-V interval and QRS complex width before and after ibutilide injection(P>0.05). After injection of ibutilide, the QTc, QT intervals, the RA ERP, RV ERP, and AVN BCL were all significantly prolonged (P<0.05). The antegrade and retrograde ERP of AP were also increased (P<0.05), with no loss of antegrade and retrograde function of AP. All patients underwent successful ablation and Torsade de pointes (Tdp) and no other adverse effects were noticed. Conclusion: Ibutilide has no effect on the conductivity of normal cardiac conduction system. Routine dosage of ibutilide can prolong ERP of AP but does not block the conductivity, with no influence on electrophysiology study and radiofrequency catheter ablation. Ibutilide has no adverse effect on patients with AVRT.

Daño reversible del nodo auriculoventricular durante la crioablación de una vía accesoria parahisiana en un niño con preexcitación intermitente

El daño del nodo auriculoventricular (NAV) constituye una de las potenciales complicaciones de la ablación por radiofrecuencia de vías accesorias parahisianas. La crioterapia, con la potencial reversibilidad a temperaturas no extremas, puede constituir una alternativa en la ablación de estas vías. Un niño con preexcitación intermitente con una vía accesoria parahisiana y crisis de taquicardia paroxística supraventricular fue sometido a un estudio electrofisiológico y la crioablación permitió la eliminación de la vía accesoria con preservación de la integridad del NAV.

Reversible Damage of the Atrioventricular Node during Cryoablation of a para-Hissian Pathway in a Child with Intermittent Pre-excitation Syndrome Damage of the atrioventricular node (AVN) is one of the potential complications in radiofrequency ablation of para- Hissian accessory pathways. Cryotherapy, with reversibility potential at non extreme temperatures, may be an alternative in the ablation of these pathways. A child with intermittent pre-excitation syndrome, para-Hissian accessory pathway and a crisis of supraventricular paroxistic tachycardia was subjected to electrophysiological assessment, and cryoablation allowed removing the accessory pathway with preserved AVN integrity.

AVRT characterized by paroxysmal occurrence that slow atrioventricular accessory pathway participatesin / 中国实用内科杂志

Objective To study the electrophysiologic characteristics of atrial-ventricular reentrant tachycardia(AVRT)characterized by paroxysmal occurrence that slow atrioventricular accessory pathway participatesin.Methods Twenty-one cases were chosen from patients receiring radiofrequency ablation therapy in Peking University People's Hospital from July in 1999 to January of 2005.The patients with slow atrioventricular accessory pathways diagnosed correctly were divided into two groups with paroxysmal tachycardia and permanent tachycardia in terms of the occurrent frequence of AVRT.The electrophysiologic features of AVRT of two groups were contrastively analyzed.Results Compared with the group of permanent AVRT,it was found that antidromic refractory period of slow atrioventricular accessory pathways was longer[(359?46)ms vs (318?31)ms,P

Role of Coronary Sinus Electrode Catheter in Catheter Ablation of the Left-side Atrioventricular Accessory Pathways

BACKGROUND: Coronary sinus(CS) electrode catheter has been used ad a very useful mapping and guiding tool in catheter ablation of the left-side atrioventricular pathway(AP). Recently, it was reporter that single catheter approach of catheter ablation of the manifest left-side AP was feaside with a comparable success rate but shorter fluoroscopy time, compared with the standard approach. This study was performed to evaluate the role of CS electrode catheter in catheter avlation of the lefr-side AP. SUBJECTS AND METHODS: Sixty-five consecutive patients(43 men, 22 women) with a single left-side AP were included in this study. The first 32 patients underwent catheter ablation with an eletrode catheter in CS(CS+ group: 19 men, 13 women: 42.3+/- 14.6 years) and the later 33 patients with no electrode catheter in CS(CS- group: 24 men, 9 women: 38.8+/- 14.1 years). APs were localized by mapping the CS in CS+ group or by mapping the mitral valve annulus in CS- group with a 4mm-tipped deflectable catheter(7F, Webster or EPT). Radiofrequency energy(RF) was delivered unipolarly at a fixed power of 30-50 volts or 30-60 seconds. AP location, succes rate, number of RF applications, fluoroscopy time, and complications were compared between 2 group. RESULTS: APs were located at the left posteroseptal wall in 2(6.2%), left posterior wall in 5(15.5%), left posterolateral wall in 3(9.3%), left lateral wall in 18(56.3%), left anterolateral wall in 4(12.5%) in CS+ group. In CS- group, there were 6(18.2%) left posteroseptal, 2(6.1%) left posterior, 5(15.2%) left posterolateral, 12(36.4%) left lateral, 8(24.2%) left anterolateral AP with no significant difference in the distribution of the APs between 2 groups. The proportions of concealed and manifest APs wrer similar in 2 groups(17/15 vs. 19/14). Twenty-eight(87.5%) of 32 APs in CS+ group and 30(90.9%) of 33 APs in CS- group were successfully ablated showing no signigicant difference in the succes rates between 2 groups. The numbers of RF applications to ablate the APs were similar between 2 groups(3.9+/-3.4 vs. 3.5+/-2.9). Total fluoroscopy times wrer also similar between 2 groups(54.3+/-33.5 minutes vs. 47.2+/-21.4 minutes). There were no major conplications in both groups. CONCLUSIONS: Radiofrequency catheter ablation of the left-side APs may be successfully performed without using a CS electrode catheter as a guide in diagmosing and localizing left-side APs.

Electrophysiologic Characteristics of Successfully Ablated Midseptal Accessory Pathway

BACKGROUND: Catheter ablation using radiofrequency energy has been established as the most important mode of treatment in patients with accessory pathway. However the ablation of midseptal accessory pathways had been recognized as being more difficult to ablate than other located pathway because of the low incidence and the difficult localization of ablation site. This paper describes the electrophysiologic characteristics of successfully ablated midseptal accessory pathway using radiofrequency energy. METHOD: Routine electrophysiologic studies were performed in 13 patients with midseptal accessorypathway. Guided by the recording of VA interval, the ablation catheter was positioned in all patients in an area bounded anteriorly by the tip electrode of the His bundle catheter and posteriorly by the coronary sinus ostium. Local electrograms during orthodromic atrioventricular reentrant tachycardia or right ventricular apical pacing were compared for 13 patients with midseptal accessory pathway and consequent 13 patients with posteroseptal accessory pathway. RESULT: 13 patients with midseptal accessory pathway; eight with constant Wolff-Parfinson-White syndrome, one with intermittent Wolff-Parkinson-White syndrome and four with concealed bypass track underwent attempts at ablation of their pathway using radiofrequency energy. 11 accessory pathways were successfully ablated without complication during the firstsession. A second attempt at ablation was made in two patients with success(one; recurred case, the other one; failed case at the first session). In the surface 12-Lead ECG, all eight patientswith constant Wolff-Pakinsin-White syndrome had not shownen Qrs complex at lead 3. Two patient with midseptal accessory pathway had transient left bundle branch block during orthodromic tachycardia. The VA interval during left bundle branch block was not change compared to that during narrow complex tachycardia in both. In all patients with midseptal accessory pathway, the VA interval in his bundle electrogram were almost similar to that in the coronary sinus ostial electrogram, which was not observed in the patients with posteroseptal accessory pathway. CONCLUSION: We suggest that VA interval during orthodromic tachycardia and right ventricular apcial pacing is the most reliable market for identifying midseptal accessory pathway, especially distinguishing from posteroseptal accessory pathway.

Cathrter Aboation of The Posteroseptal Accessory Pathways

BACKGROUND: The ablation of accessory pathways(APs) using radiofrequency(RF) energy has been establihed as a primary modality of treatment for atrioventricular reentranr tachycardia with probrn safety and high rate of success. However, the ablation of posteroseptal(PS) APs had been recognized as being more difficult to ablate than those in other location because of the complex three dimensional anatony of the posterior apace, and multifarious approaches have been proposed. We analyzed electrophysiologic characteristics and results of catheter ablation of 70 consecutive patients, who underwent RF ablation of PS APs with or without booster direct current(DC) shock. METHODS: Teh AP location was confirmed to be in the PS region, ablation was attepmted at the atrial aspect of the tricuspid annulus adjacent to the coronary sinus ostium, within the coronary sinus in couding middle cardiac vein, or underneath the mitral annulus close to the septum using retrograde transaortic approach if deemed necessory. A continuous, unmodulated sine wave radiofr-equency generator was used as the source of energy for ablation. The site was considered optimal for ablation when the electrogram obtained from the ablation catheter had one or more of the following characteristics : (1) short VA intervals with an A : V ratio of