Orthodromic Atrioventricular Tachycardia in Wolff-Parkinson-White Syndrome with Two Accessory Pathways Participation during the Same AVT

Case report of a 49-year-old patient with Wolff-Parkinson-White syndrome, very symptomatic, with apparent parahisian pathway who, during an electrophysiological study, presented orthodromic atrioventricular tachycardia, featuring two accessory pathways, retrogradely, the parahisian pathway and a hidden left posterolateral pathway, during the same tachycardia, alternating the retrograde pathway of tachycardia without interruption.

Accuracy of the Electrocardiogram in Localizing the Accessory Pathway in Patients with Wolff-Parkinson-White Pattern / Acurácia do Eletrocardiograma na Localização da Via Acessória em Pacientes com Padrão de Wolff-Parkinson-White

Abstract Background: There are currently several electrocardiographic algorithms to locate the accessory pathway (AP) in patients with Wolff-Parkinson-White (WPW) syndrome. Objective: To compare the ability of electrocardiographic algorithms in identifying the location of the AP in patients with WPW pattern referred for ablation. Methods: Observational, cross-sectional, retrospective study with 111 patients with WPW syndrome referred for AP ablation. The electrocardiogram (ECG) obtained prior to the ablation was analyzed by an experienced observer who consecutively applied seven algorithms to identify non-invasively the AP. We then compared the location estimated with this assessment with that obtained in the electrophysiological study and calculated the agreement rates. Results: Among the APs, 59 (53.15%) were distributed around the mitral annulus and the remaining 52 (46.85%) were located around the tricuspid annulus. The overall absolute accuracy of the algorithms evaluated varied between 27% and 47%, increasing to between 40% and 76% when we included adjacent locations. The absolute agreement rate by AP location was 2.00-52.20% for septal APs (n = 51), increasing to 5.90-90.20% when considering adjacent locations; 7.70-69.20% for right APs (n = 13), increasing to 42.90-100% when considering adjacent locations; and 21.70-54.50% for left APs (n = 47), increasing to 50-87% when considering adjacent locations. Conclusion: The agreement rates observed for the analyzed scores indicated a low discriminative ability of the ECG in locating the AP in patients with WPW.

Resumo Fundamento: Existem atualmente vários algoritmos eletrocardiográficos para localizar a via acessória (VA) em pacientes com síndrome de Wolff-Parkinson-White (WPW). Objetivo: Comparar a capacidade discriminativa dos algoritmos eletrocardiográficos na localização da VA no padrão de WPW em pacientes encaminhados para ablação. Métodos: Estudo observacional, transversal e retrospectivo, incluindo 111 pacientes com síndrome de WPW encaminhados para ablação da VA. O eletrocardiograma (ECG) prévio à ablação foi analisado por um observador experiente que aplicou consecutivamente sete algoritmos para identificar a VA de forma não invasiva. A localização estimada com esta avaliação foi comparada à obtida no estudo eletrofisiológico e as taxas de acerto foram calculadas. Resultados: Entre as VAs, 59 (53,15%) estavam distribuídas ao redor do anel mitral e as restantes 52 (46,85%) em torno do anel tricúspide. O acerto global absoluto dos algoritmos em estudo variou entre 27% e 47%, aumentando para 40% a 76% quando incluímos localizações adjacentes. O acerto absoluto em função da localização da VA foi o seguinte: para as VAs septais (n = 51) variou entre 2% e 52,20% (5,90% e 90,20% incluindo localizações adjacentes), para as VAs direitas (n = 13) variou entre 7,70% e 69,20% (42,90% e 100%, incluindo localizações adjacentes), para as VAs esquerdas (n = 47) variou entre 21,70% e 54,50% (50% a 87%, incluindo as localizações adjacentes). Conclusões: Os índices de acerto observados para os escores analisados indicaram uma reduzida capacidade discriminativa do ECG na localização da VA em pacientes com WPW.

Intermittent, subtle change of ST segment in narrow QRS regular tachycardia

No abstract available.

Successful Ablation of Resistant Left Lateral Accessory Pathway and Coexisting Atypical Atrioventricular Nodal Reentrant Tachycardia

A 41-year-old male was presented with drug-resistant supraventricular tachycardia. Electrophysiological study confirmed that the supraventricular tachycardia was caused by dual atrioventricular nodal pathways and a left lateral accessory pathway (AP). The left lateral AP was resistant to traditional endocardial ablation, but was successfully eliminated by radiofrequency ablation via the intracoronary sinus approach.

HISTOLOGICAL EXAMINATION OF THE A-V NODE AND A-V BUNDLE IN HUMAN HEARTS / 解剖学报

The morphology and position of the AV node and AV bundle were observed in 13 human hearts with serial sections. 1.the AV node is a long sagittal flatt ened structure, its transverse section is triangular in shape with a right convex surface, sometimes the cross section is fusiform or half oval in shape. Its size is 3.5x3.3x1.1 mm in adult. In 5 cases the endocardium lying on the right surface of the AV node is elevated.2.The AV node is situated in the upper border of the atrioventricular septum (between the levels of the attachment lines of the mitral and tricuspid valves). The adult AV node is 1.8-5.8 mm anterior to the coronary sinus orifice, 0.3-0.7 mm from the endocardium of the right atrium, 3.3-7.5 mm above the upper border of the septal leaflet of the tricuspid valve. The left surface of the AV node contacts with the central fibrous body.3.The AV node can be divided in 2 parts: superficial and deep, the fibers of the super ficial part are longitudinal in sections and end in the lower border of the AV node. In one case, the deep part is subdivided in an upper part and a lower part. In the specimens in which the right atrial endocardium lying on the right surface of the AV node is elevated, the overlaying fibers end in the endocardium. At the upper border, right surface, and posterior margin of the AV node, there are atrial fibers ending to the AV node. 4. The adult AV bundle is 5.7-7.9 mm long, 1.1-1.5 mm in diameter. Its anterior part is on top of the muscular interventricular septum in 7 specimens, on its left surface in 3 specimens, and in the substance of the muscular interventricular septum in 2 specimens. In one case its course is very special, at first on the top of muscular interventricular septum, then at its left surface, finally in the substance of the right part of the muscular interventricular septum.