Para-Hisian Accessory Pathway and Paroxysmal Second Degree Atrio-Ventricular Block in a Child

Para-Hisian Accessory Pathway and Paroxysmal Second Degree Atrio-Ventricular Block in a Child

Silvia Farruggio1 MD, Giuseppina Nicita1, MD, Elio Caruso1 MD, PhD.


1. Mediterranean Pediatric Cardiology Center, San Vincenzo Hospital, Taormina (ME), Italy.


Corresponding Author: Silvia Farruggio, Pediatric Cardiology, San Vincenzo Hospital, Contrada Sirina, 98039, Taormina (ME), Italy.

Copy Right: © 2023, Silvia Farruggio, This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Received Date: May 11, 2023

Published Date: June 01, 2023

DOI: 10.1027/marcy.2023.0213

 

Abstract

We report a rare case about 13 years old boy, with a previous history of syncope after painful bodily trauma. His ECG showed ventricular preexcitation and 24 hours ECG Holter showed a paroxysmal second degree atrio-ventricular block type one (Luciani-Wenckeback) during sleeping.

Transcatheter electrophysiologycal study showed a para-Hisian accessory pathway sited 5.1 mm to His area and no arrhythmias-induced.

Keywords: Accessory pathway – Atrio-ventricular block – pediatric arrhythmias – electrophysiology study

 

Abbreviations

AP: Accessory Pathway

AV: Atrio-Ventricular

AVB: Atrioventricular Block

CS: Coronary Sinus

EAM: Electroanatomic Map

EPS: Electrophysiological Study

FAM: Fast Anatomic Map

HR: Heart Rate

RA: Right Atrium

RV: Right Ventricle

AH: Atrial- His Bundle

HV: His-Ventricular


Para-Hisian Accessory Pathway and Paroxysmal Second Degree Atrio-Ventricular Block in a Child

Case Report

We report a rare case about ventricular preexcitation and second degree atrio-ventricular block (AVB) type one (Luciani-Wenckeback) during sleeping. A 13 years old boy was referred at our center for his-tory of two syncopes after painful bodily traumas, never palpitations reported. In another hospital neu-rological assessment and myocardial enzymes were normal. His ECG showed sinus rhythm at heart rate (HR) of 60 bpm, ventricular preexcitation with an anterograde conducting pathway with positive delta waves in the inferior leads (II, III, and aVF) and the lateral precordial leads (V3 through V6); negative delta waves were present in lead V1 and often in V2. Leads I and aVL have positive delta waves (negative in aVR). Normal QRS and QTc intervals (Fig.1).

 

According to the ECG the ventricular preexcitation seemed to involve an anteroseptal accessory pathway (AP). The ECG Holter 24 h in another hospital showed a paroxysmal second degree AVB type one (Luciani-Wenckeback) during sleeping (Fig. 2) and an uncertain supraventricular tachycardia referred from another hospital.

The patient was referred to our center and we decided to assess the arrhythmic risk of the AP and the atrio-ventricular (AV) conduction through the transcatheter electrophysiological study (EPS). We de-cided in agreement with family for transcatheter EPS rather than transesophageal EPS to stratify the arrhythmic risk, because of the uncertain supraventricular tachycardia, and to localize the AP as its as-sociation with AVB is very rare.

 

The echocardiogram showed normal sequential cardiac anatomy, no patent forame ovale, normal ejection fraction, no valvular regurgitation or stenosis, no pericardial effusion.

The procedure was planned as a non-fluoroscopic procedure. Vascular access was obtained without ul-trasonographic guidance. Informed consent was obtained from family.

 

In view of the paroxysmal second-degree AVB was also evaluate the loop recorder subcutaneous- implantation if a AV nodal disease had been diagnosed.

The procedure was performed under general anesthesia to avoid map shifts caused by patients’ movements and endotracheal intubation. The procedure was performed with the guidance of an elec-troanatomic map (EAM) system CARTO3 (Biosense Webster, Diamond Bar, CA, USA) without using fluoroscopy to reduce the risk of ionizing radiations1-2.

The CARTO3 EAM system, providing the visualization of multiple catheters, was used to navigate the venous system and to perform a right atrium EAM in order to place all the catheters in the heart.

 

Using the Seldinger technique three sheaths were inserted via the right femoral vein: 8 fr for Navistar tip 4 mm catheter, into the right atrium for the EAM, 7 fr for decapolar CS catheter and 6 fr for the quadripolar catheter. A conventional 4 mm quadripolar steerable catheter, with a deflectable tip to fa-cilitate electrophysiological mapping of the heart and to create a matrix (Navistar, Biosense Webster, Inc.)  was advanced into the right atrium to obtain 3-dimensional (3D) fast anatomic map (FAM) and to label the anatomic landmarks, including the inferior and superior caval veins, the right atrium (RA), the coronary sinus (CS), His area, and the tricuspid valve annulus.

The reconstruction of the right atrium was obtained by the FAM algorithm. This method continuously records movements of the Navistar catheter. On the basis of volume sampling, a surface reconstruc-tion was built in accordance with the set resolution level. The geometric reconstruction of the right atrium started positioning the Navistar catheter on the superior vena cava. The mapping catheter was then withdrawn from the superior vena cava through the right atrium down to the inferior vena cava, touching the endocardial surface of the lateral, septal, anterior, and posterior walls and tagging specif-ic anatomic landmarks such as the His bundle and the tricuspid ring. The navigation inside the cham-ber was guided by the integration of the direct visualization of the mapping catheter provided by the CARTO3 system and the analysis of the electrograms recorded from the tip of the roving catheter.

 

This matrix allowed for the advanced catheter localization of any non–sensor-equipped catheter such as the decapolar catheter advanced into the CS or the quadripolar catheter localized on the His. The His position was identified and marked on the 3D FAM of the RA as a reference.

A decapolar catheter was advanced in the CS and a quadripolar catheter placed in the His area/right ventricle.

The coronary sinus catheter was used as the system reference. To avoid introducing an extra sheath in-to children, we did not employ a fourth catheter, instead placing the high right atrium catheter in the His bundle when needed. In patients with a baseline sinus rhythm, we performed standard pro-grammed stimulation and burst pacing manoeuvres to induce atrial tachycardia.

 

Electrophysiological study was performed using standard protocols to assess conduction properties of the AP and arrhythmia inducibility.

The intracardiac recordings showed normal atrial- His bundle (AH) and His-ventricular (HV) inter-vals.

Early ventricular activation indicative of a para-Hisian AP was noted in the catheter’s distal pair (CS 9-10), which had not advanced fully into the coronary sinus, which was sited 5.1 mm to the His area (Fig. 3). Basal cycle length was 740 ms.

Atrial stimulation was initiated with a 600-ms cycle. Wenckeback cycle was calculated after incre-mental atrial stimulation at 330 ms. Each atrial impulse was always conducted to the ventricle over the AP. Programmed atrial stimulation (600 ms) with single extrastimuli (S1) from 500 ms to 280 ms was performed and a refractory AV nodal period was calculated at 280 ms.

 

Atrial stimulation with double and triple extrastimuli didn’t induce arrhythmias.

The same protocol was repeated with the use of isoproterenol infusion intravenously (8 μg/min) with-out inducing arrhythmias. 

The EPS has been ended as normal nodal conduction and the low arrhythmic risk of the AP. No fluor-oscopy was used. The loop recorder has not been implanted because of normal AV conduction and no arrhythmias induced from the EPS.

Based on these data, it was evident that the true mechanism of syncope was vagal stimulation subse-quently to painful stimulus. We suspected that the second AVB recorded during sleeping is due to epi-sodes of vagally mediated AVB occurring often during the night.

 

Syncope in a patient with manifest ventricular preexcitation usually led to indicate a fast conduction to the ventricle over the AP, for this reason the EPS has been conducted to exclude an AP contributing to the mechanism of syncope.

Although this mechanism explains syncope in the most patients with preexcitation, a detailed research for the causal mechanism should be based on the interpretation of the full medical history, considering the second-degree AV block, the painful stimulus and not only on the presence of an AP.

In our literature review, we didn’t find cases in pediatric population with similar clinical and electro-physiological characteristics3, few cases have been reported only in adulthood 4-6.

 

Moret, Schwartz and White wrote an historical manuscript about Wolff-Parkinson-White syndrome coexisting with second degree AV block describing only 8 cases in the 1959 and giving importance and support to their theory of accelerated conduction through the normal pathway 7.

In conclusion, we described a unique case of paroxysmal second degree AVB type one (Luciani-Wenckeback) and para-Hisian AP in a 13 years old boy. The simultaneous presence of second-degree AVB with a para-Hisian AP is rare.


In the baseline intervals of the EPS, we found a normal AH and HV intervals in the His-bundle cathe-ter, leading us to suspect that the paroxysmal second-degree AVB was vagally mediated and not the cause of syncope. In this case, the AP was the preferential way of conduction because during protocol of stimulation the intracavitary electrogram showed always the ventricular preexcitation even in the context of Wenckeback cycle and AV nodal refractory period assessments. The closeness of His area and AP can explain the association of this phenomenon.

 

References

 

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2. Gerber TC, Carr JJ, Arai AE, Dixon RL, Ferrari VA, Gomes AS, Heller GV, et al. Ionizing radiation in cardiac imaging: A science advisory from the American Heart Association Committee on Cardiac Imaging of the Council on Clinical Cardiology and Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention. Circulation 2009; 119:1056–1065.

3. Palanca V, Quesada A, Roda J, Villalba S, Mihi N, Velasco J. Sínsope por bloqueo auriculoventricular completo en un paciente con preexcitación [Intermittent atrioventricular block in an accessory pathway associated with complete infrahissian block]. Rev Esp Cardiol. 2004;57(4):363-366.

4. Barbhaiya C, Rosman J, Hanon S. Preexcitation and AV block. J Cardiovasc Electrophysiol. 2012;23(1):106-107..

5. Tan HL, van der Wal AC, Campian ME, et al. Nodoventricular accessory pathways in PRKAG2-dependent familial preexcitation syndrome reveal a disorder in cardiac development. Circ Arrhythm Electrophysiol. 2008;1(4):276-281. Arias MA, Pachón M, Casares-Medrano J, Puchol A. Ventricular preexcitation and atrioventricular block?. Heart Rhythm. 2013;10(1):142-143.

6. P.R. Moret, M.L. Schwartz, T.J. White; The Wolff-Parkinson-White Syndrome and Second Degree Heart Block: Report of a Case and a Discussion of the Significance of the Association of These Phenomena. Cardiologia 1 January 1959; 34 (1): 43–52. 

 

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