Importance of the Activation Sequence of the His or Right Bundle for Diagnosis of Complex Tachycardia Circuits

In this review, we emphasize the unique value of recording the activation sequence of the His bundle or right bundle branch (RB) for diagnoses of various supraventricular and fascicular tachycardias. A close analysis of the His to RB (H-RB) activation sequence can help differentiate various forms of supraventricular tachycardias, namely atrioventricular nodal reentry tachycardia from concealed nodofascicular tachycardia, a common clinical dilemma. Furthermore, bundle branch reentry tachycardia and fascicular tachycardias often are included in the differential diagnosis of supraventricular tachycardia with aberrancy, and the use of this technique can help the operator make the distinction between supraventricular tachycardias and these other forms of ventricular tachycardias using the His-Purkinje system. We show that this technique is enhanced by the use of multipolar catheters placed to span the proximal His to RB position to record the activation sequence between proximal His potential to the distal RB potential. This allows the operator to fully analyze the activation sequence in sinus rhythm as compared to that during tachycardia and may help target ablation of these arrhythmias. We argue that 3 patterns of H-RB activation are commonly identified—the anterograde H-RB pattern, the retrograde H-RB (right bundle to His bundle) pattern, and the chevron H-RB pattern (simultaneous proximal His and proximal RB activation)—and specific arrhythmias tend to be associated with specific H-RB activation sequences. We show that being able to record and categorize this H-RB relationship can be instrumental to the operator, along with standard pacing maneuvers, to make an arrhythmia diagnosis in complex tachycardia circuits. We highlight the importance of H-RB activation patterns in these complex tachycardias by means of case illustrations from our groups as well as from prior reports.

Ventricular tachycardia?

A 59-year-old patient presented with “suspicion of ventricular tachycardia” because of “abnormalities in the long-term ECG” (Figure. 1). Cryoablation of the slow path had already taken place beforehand, in the case of slow-fast atrioventricular nodal reentry tachycardia.

Voltage bridge mapping in atrioventricular nodal reentry tachycardia ablation in adult population: results from a multicenter registry

Funding Acknowledgements Type of funding sources: None. Background The presence of Low Voltage Bridge (LVB) in Atrioventricular Nodal Reentry Tachycardia (AVNRT) ablation has been described in children populations. Slow pathway ablations visualizing and targeting the LVB has been described to be safe and effective. However, the incidence of LVB in AVNRT ablation has not been widely explored in adult population. Purpose We aim to investigate the presence of LVB in adult patients (pts) undergoing AVNRT ablation, and the relationship between the LVB and the successful ablation site. We have also investigated the correlations between the Koch’s triangle (KT) anatomy and biophysical pts data. Methods The observational registry prospectively collected data of 165 pts. undergoing AVNRT ablation guided by 3D electroanatomical mapping system (EnSite - Abott, St Paul, MN) in 6 EP centers. Gender: 90F – 75M (55% - 45%) - Age: 57 ± 17 ys (min 15 – max 87) - Weight: 73 ± 15 kgs (min 42 - max 150) Prior of ablation a voltage map of KT was created using diagnostic and ablation catheters. We define as Type I LVB a clear, long area of low voltage within the KT between the CS ostium and the AV node with the base on the edge of the tricuspid annulus and Type II LVB a narrow low voltage channel between normal-voltage regions with the base on the edge of the tricuspid annulus. The relationship between LVB and successful site was evaluated at the end of the procedure. KT anatomical data were correlated to gender, age and weight. Results The LVB was identified in 134 pts (81%) with a prevalence of type I (91 - 68%) over type II (33 - 25%). In 10 pts (7%) the LVB did not match type I nor type II. When an LVB was identified, the correspondence between the LVB and the successful ablation site was verified in 117 pts (87%). In addition, a shorter RF time was applied when an LVB was found (396s vs 298s; p = 0.03). Strong correlations between KT anatomy and biophysical pts data were not identified. The distance between His electrograms and the successful ablation site weakly correlated (ρ = -0.24, p < 0.01) with pts age suggesting a shortening in the distance with age progression. Conclusion The visualization of the Low Voltage Bridge may be a helpful tool to guide AVNRT ablation in a large cohort of pts; furthermore it is associated with reduced RF applications time. The KT characteristics are difficult to be predicted a priori according to patient gender, age or weight.

The prevalence of familial form of atrioventricular nodal reentry tachycardia in south-eastern regions of Poland

Introduction Atrioventricular nodal reentry tachycardia (AVNRT) is one of the most common regular supraventricular arrhythmia referred for catheter ablation (CA). Although, several families with familial form of AVNRT (FAVNRT) in Subcarpathia province (SP, Poland), the comparison or prevalence of FAVNRT and comparison of their incidence in other provinces in Poland were not prospectively validated. Methods Data was derived from prospective multicenter registry of CA (ELEKTRO- ELMedica Network). Between year 2010 to 2018, the clinical data of 1544 patients with invasively documented AVNRT were verify for family history of FAVNRT. From December 2016 to March 2019 each patient with AVNRT were consulted with detailed family history and family residence origin with up to three-generation pedigree. Families with substantiate form of FAVNRT (at least two persons from the family after invasive validation of AVNRT and CA) divided into three groups according to their origin. Results From 1544 recruited patients 932 had origin in south-eastern provinces (SEP) of Poland [n=379, from SP; n=34, from Lubelskie; n=214, from Lesser Poland; and n=305 from Holy Cross]. The rest of the group (n=612) consisted of patients from other, not SEP parts of the country – other part of Poland (RPP). Finally, 45 (2,91%) patients from 24 families had diagnosed FAVNRT. The incidence of FAVNRT was significantly higher in SEP than RPP (4.02% vs 1.17%). Moreover, patients from SP has the highest prevalence of FAVNRT (6.33%) as compared to other provinces of SEP (2.47%). In SP and in bordering SEP provinces as well as the RPP appropriate risk (according to previous region) of FAVNRT was respectively 2.67 (95% CI: 1.36–5.23; P<0.004), 2.14 (95% CI: 0.86–5.34; P<0.10) according to reference RPP were observed. Conclusion Based on Hill's Criteria for Causality observed biological monotonic risk gradient of FAVNRT is proving geographical cause of increased prevalence of FAVNT. The closer they are the higher they is to the most endangered provinces in Poland- SP that also adjoined to Ucraine and Slovakia. Further, international, trans-border cooperation and genetic testing are required to validate genetic impact of FAVNRT in past Galicia region of Central Europe. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Study is funding by the research grant DI2015 021945 from budget resources in 2015 to 2017, as a research project in “Diamentowy Grant” program from “Narodowe Centrum Badan i Rozwoju (PL)”.