Case Report, Int J Cardiol Res Vol: 12 Issue: 5
Successful Atrioventricular Nodal Re-entrant Tachycardia Ablation with High Density Mapping of the Voltage Bridge and Propagation Analysis using Coherent: A New Workflow
Paolo Sabbatani* and Alessandro Corzani
1Department of Cardiology, Bufalini Hospital, Cesena, Italy
*Corresponding Author: Paolo Sabbatani,
Department of Cardiology, Bufalini
Hospital, Cesena, Italy
E-mail: paolo.sabbatani@auslromagna.it
Received date: 04 August, 2023, Manuscript No. ICRJ-23-109193;
Editor assigned date: 08 August, 2023, PreQC No. ICRJ-23-109193 (PQ);
Reviewed date: 22 August, 2023, QC No. ICRJ-23-109193;
Revised date: 29 August, 2023, Manuscript No. ICRJ-23-109193 (R);
Published date: 05 September, 2023, DOI: 10.4172/2324-8602.1000518
Citation: Sabbatani M, Corzani A (2023) Successful Atrioventricular Nodal Re-entrant Tachycardia Ablation with High Density Mapping of the Voltage Bridge and Propagation Analysis using Coherent: A New Work low. Int J Cardiovasc Res 12:5.
Abstract
This case report refers to three case of patients who underwent Ablation of Nodal Reentrant Tachycardia (AVNRT) with the aid of high-density mapping catheters (Pentaray and Octaray) to identify and better characterize the zone of the slow pathway in Koch’s triangle and the voltage bridge. So it become essential to perform an accurate mapping of the Koch’s triangle with the 3D Electroantomical (EA) mapping system (CARTO® 3 Webster) to accurately define the ablation target area. As it results, in all three cases a more precise localization of the slow pathway is obtained and the procedure time and the number of radiofrequency deliveries are reduced compared to the traditional approach. Furthermore, the result is even more evident with the use of octaray catheter which allows to collect a large number of points for an even more precise mapping. This is the first case of use of this type of catheter in the setting of Ablation of Nodal Reentrant Tachycardia (AVNRT) ablation.
Keywords: Ablation of Ablation of Nodal Reentrant Tachycardia (AVNRT),
High density non-contact mapping, Coherent mapping, Voltage
bridge, Koch triangle mapping
Introduction
Atrioventricular Nodal Reentry Tachycardia (AVNRT) is the most common supraventricular tachycardia inducible in the electrophysiology laboratories [1,2]. In the 90s, ablative therapy of slow pathway proved to be the treatment of choice for this type of arrhythmia. Although the procedure is highly successful with 97% of success rate, 1%, 3%-4% of cases may recur and in less than 1% of the cases heart block can occur [3]. The slow pathway is located along the inferior aspect of the Koch’s triangle towards the tricuspid valve with an atrial voltage that is between 1/10 and 1/2 the ventricular voltage. Ablative therapy with Radio Frequency (RF) is delivered in the region of the slow pathway until either a junctional response is produced or non inducibility with or without Atrioventricular (AV) nodal echo beats induction is achieved. Ablation success is measured by the inability to induce Ablation of Nodal Reentrant Tachycardia (AVNRT) and a change in Atrioventricular (AV) nodal properties (induction of a single echo beat) under isuprel infusion [4]. Abolition of Ablation of Nodal Reentrant Tachycardia (AVNRT) inducibility in the presence of isoproterenol challenge is the most reliable marker for ablation success [5].
Voltage-guided ablation of the slow pathway in Ablation of Nodal Reentrant Tachycardia (AVNRT) is a fundamental change from the traditional anatomy-guided approach within the Koch’s triangle. In particular, the use of a voltage gradient map emphasizing the Low Voltage Bridge (LVB) may help in the identification of the Slow Pathway (SP) hence guiding the radiofrequency ablation [6].
To properly identify the Slow Pathway (SP) associated Low Voltage Bridge (LVB) it is necessary to define the relationship between the Low Voltage Bridge (LVB) and the anatomic Atrioventricular (AV) node. The Slow Pathway (SP) associated Low Voltage Bridge (LVB) is observed to connect the high voltage region at the coronary sinus ostium to the Atrioventricular (AV) nodal region (Type I). In some cases the Slow Pathway (SP) associated Low Voltage Bridge (LVB) is a narrow band between adjacent high-voltage regions (Type II) [7].
In light of this, it becomes essential to perform an accurate mapping of the Koch’s triangle with 3D Electroanatomical (EA) mapping systems to accurately define the ablation target area which would not be possible with the classical fluoroscopy-based approach [8].
With the aim to precisely localize the slow-pathway area, we developed a novel workflow using Electroanatomical (EA) mapping and multipolar mapping catheters and present three clinical cases of Ablation of Nodal Reentrant Tachycardia (AVNRT) treated with the proposed method.
Case Presentation
All patients underwent a complete Electrophysiology (EP) study before ablation. In all cases, the CARTO® 3 cardiac mapping system (Biosense Webster, Irvine, C-Arm (CA)) was used to avoid fluoroscopy exposure and to achieve accurate localization of the ablation target.
A multipolar diagnostic catheter (Pentaray™ or Octaray™, Biosense Webster) was used to create a Fast-Anatomical Map (FAM) of the right atrium allowing to advance the other diagnostic catheters without the use of fluoroscopy. When the map was completed, the Pentaray™ or Octaray™ catheter was positioned such that one spline recorded the signal. Additionally, a decapolar diagnostic catheter (Inquiry, Abbott Medical 6F) was positioned in the Coronary Sinus (CS) and a Quadripolar catheter (Viking, Abbott Medical, 6 F) was advanced in the right ventricle.
The diagnosis of Ablation of Nodal Reentrant Tachycardia (AVNRT) was performed according to standard pacing protocols [9]. Once the diagnosis of Ablation of Nodal Reentrant Tachycardia (AVNRT) was made, a bipolar voltage map of the Koch’s triangle was acquired in Sinus Rhythm (SR) using the Pentaray™ or Octaray™ catheter, setting the following filters of the Confidense™ module: Tissue Proximity Indicator (TPI) activated, Local Activation Time (LAT) stability set to 6 ms, position stability set to 6 mm, cycle length range adjusted to include only beats in SR. The color bar of the bipolar voltage map was set to range between approximately 0.1 mV and 1 mV to visualize the voltage bridge [10].
Before the analysis of the activation pattern, the inferior vena cava, the superior vena cava and the tricuspid valve were delineated with the anatomical structure tool of the CARTO® 3 system.
Next, the coherent algorithm was launched, generating an activation map showing the wave front propagation in the slow pathway region. To precisely identify the target ablation site, we looked for the thicker arrows generated by the coherent algorithm in the voltage bridge area. These thicker arrows correspond to the slowest conduction site. The slowest conduction site was then considered as the ablation target area.
Once the ablation target area was identified, The Smart Touch® (ST) Surround Flow (SF) catheter was advanced in the Right Atrium and Radiofrequency (RF) was delivered with a power between 25 Watts and 30 Watts. Afterwards, a new Electrophysiology (EP) study was performed to verify if the Ablation of Nodal Reentrant Tachycardia (AVNRT) was still inducible. The procedure was considered concluded if non-inducibility of Ablation of Nodal Reentrant Tachycardia (AVNRT) was observed in basal condition and under isuprel intravenous administration at dosage of 1/20 gamma/ kg/min by adjusting the infusion to the heart rate response.
Below we report three clinical cases of Ablation of Nodal Reentrant Tachycardia (AVNRT) ablation using the proposed workflow. In none of the cases fluoroscopy was used for the entire procedure.
Case 1
The first patient is a 70-year-old woman without organic heart disease, suffering from arterial hypertension under pharmacological treatment. For years she has had frequent episodes of paroxysmal tachycardia sensitive to adenosine with evidence of probable nodal reentrant arrhythmia on the electrocardiographic tracing. For this reason, the patient underwent an Electrophysiology (EP) study.
A bipolar and Coherent map of the Koch’s triangle were acquired with the Pentaray catheter in 5 min resulting in 1.952 EA points collected (Figure 1).
Figure 1: Top left: Bipolar map of the Koch’s triangle (delineated with the white line), showing the voltage bridge area. Top right: Coherent vectors visualized on top of bipolar map. Blue dots indicate optimal sites (the corresponding signal recorded by the ablation catheter is indicated by the white circle). Bottom: Ablation lesions red and light red tags in the optimal site and corresponding junctional beats during ablation. Coronary Sinus (CS).
To find the ablation target area we focused the attention on the Low Voltage Bridge (LVB) zone and we looked for the thicker vectors of the Coherent map, corresponding to the slowest conduction zone. We then applied Radiofrequency (RF) in the target area.
To achieve the clinical endpoint, two Radiofrequency (RF) applications were required, with a total Radiofrequency (RF) time of 120 sec.
Radiofrequency (RF) was delivered with a power range of 20 watt to 30 watt and an average contact force of 13 gr.
The total procedure time was 90 min including the Strain Energy Function (SEF) at the beginning and at the end of the procedure.
Case 2
A 40-year-old man, smoker, suffering from arterial hypertension and dyslipidemia for over 15 years, reported almost daily episodes of paroxysmal tachycardia which responded to vagal and Valsalva maneuvers. The electrocardiogram recorded during the arrhythmia showed narrow QRS tachyarrhythmia with a heart rate of 180 bpm.
For this case, a bipolar and Coherent map of the Koch triangle were acquired with the Pentaray catheter in 10 min resulting in 1.537 points collected (Figure 2).
Figure 2: Left: Bipolar map of the Koch’s triangle delineated with the white line, showing the voltage bridge area. Right: Coherent vectors visualized on top of bipolar map and ablation lesions red tags in the optimal site signal in the white circle and corresponding junctional beats during ablation.
To achieve the clinical endpoint, two Radiofrequency (RF) applications were required, with a total Radiofrequency (RF) time of 121 sec.
Radiofrequency (RF) was delivered with a power range of 20 watt to 30 watt and an average contact force of 8 gr.
The total procedure time was 90 min including the Strain Energy Function (SEF) at the beginning and at the end of the procedure.
Case 3
A 55-year-old man with no previous cardiac history presented several times to the emergency room for episodes of prolonged arrhythmia arising both at rest and after physical effort. The arrhythmia did not respond to vagal maneuvers. The electrocardiographic tracing recorded during the arrhythmia showed a typical appearance of nodal reentry and the patient underwent transcatheter Electrophysiology (EP) study.
For this case, a bipolar and Coherent map of the Koch triangle were acquired with the octaray catheter (8 Fr, spacing 2-2-2-2-2) in 4 min and 60 secs resulting in 13706 points collected.
To achieve the clinical endpoint, one Radiofrequency (RF) application was required, with a total Radiofrequency (RF) time of 60 sec.
Radiofrequency (RF) was delivered with a power range of 20 watt to 30 watt and an average contact force of 10 gr.
The total procedure time was 70 min including the Strain Energy Function (SEF) at the beginning and at the end of the procedure (Figure 3).
Figure 3: Top: Bipolar map obtained with Octaray and corresponding signals in the Koch’s triangle area, including the signal (white circle). Bottom left: Coherent velocity vectors overlaid on bipolar map. Bottom right: Ablation tags and junctional beats during ablation.
Results and Discussion
In this Case Report we present a novel workflow for the treatment of Ablation of Nodal Reentrant Tachycardia (AVNRT) using Electroanatomical (EA) mapping. The three cases presented indicate that high density bipolar mapping of the Koch’s triangle combined with the Coherent propagation map allow to precisely identify the target ablation zone, resulting in a very limited number of Radiofrequency (RF) applications to achieve the clinical endpoint (≤ 2 applications).
As shown in the third case, the use of Octaray enabled to acquire a higher number of Electroanatomical (EA) points with a shorter total procedure time compared to the cases where the Pentaray was used. This is possible thanks to the increased number of electrodes (48) of the Octaray compared to the Pentaray catheter. Moreover, the smaller electrode size of the Octaray catheter, allows a higher signal resolution, resulting in an increased accuracy when defining the ablation target area. This increased accuracy further reduces the number of RF applications required to achieve the clinical endpoint (Octaray case-1 application, Pentaray cases-2 application each).
The major complication during Ablation of Nodal Reentrant Tachycardia (AVNRT) ablation is Atrioventricular (AV) block due to the proximity of the normal conduction system. With the proposed workflow, the combined information of the bipolar map and the Coherent vector velocity map may help to precisely identify the target ablation area reducing the risk of complications. Furthermore, this workflow allows Ablation of Nodal Reentrant Tachycardia (AVNRT) ablation without the use of fluoroscopy thanks to the mapping system.
Conclusion
In conclusion, the utilization of high-density mapping of the voltage bridge combined with coherent propagation analysis represents a promising new workflow for successful Atrioventricular Nodal Reentrant Tachycardia (AVNRT) ablation. This innovative approach enhances our understanding of the intricate electrophysiological mechanisms underlying AVNRT, leading to improved targeting and precision during ablation procedures. By identifying critical regions within the atrioventricular node and comprehensively assessing the propagation dynamics, this workflow optimizes the outcome of AVNRT ablation while minimizing potential complications. This advancement holds great potential for refining the management of AVNRT, offering patients a more effective and safer treatment option. Nevertheless, further studies and validation in diverse patient populations are warranted to establish the consistent efficacy and broader applicability of this technique, ultimately shaping the future landscape of arrhythmia intervention.
Acknowledgements
The Authors thank Rosalia Martino clinical support specialist, Matteo Fioravanti sales & clinical specialist and Jovana Janjic clinical support specialist of Biosense Webster for their valuable support.
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