Feasibility of the transseptal approach for mapping and ablation in patients with ventricular aneurysm-related ventricular tachycardia with a steerable sheath: A retrospective study

Lian Chen; Min Tang; Xiaoqing Ren; Pihua Fang; Jingtao Zhang; Tianjie Feng; Zhengqin Zhai; Xiaonan Dong; Shu Zhang

doi:10.4103/ijhr.ijhr_15_21

ORIGINAL ARTICLE

Year : 2021 | Volume : 6 | Issue : 2 | Page : 85-89

Feasibility of the transseptal approach for mapping and ablation in patients with ventricular aneurysm-related ventricular tachycardia with a steerable sheath: A retrospective study

Lian Chen, Min Tang, Xiaoqing Ren, Pihua Fang, Jingtao Zhang, Tianjie Feng, Zhengqin Zhai, Xiaonan Dong, Shu Zhang
State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China

Date of Submission	30-Oct-2021
Date of Decision	03-Dec-2021
Date of Acceptance	06-Dec-2021
Date of Web Publication	28-Dec-2021

Correspondence Address:
Dr. Min Tang
State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005
China

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/ijhr.ijhr_15_21

Abstract

Background: A retrograde transaortic access might be limited in mapping and ablation for some left ventricular (LV) arrhythmias. We examined the feasibility and safety of a transseptal approach for catheter ablation of LV aneurysm (LVA)-related ischemic ventricular tachycardia (VT). Subjects and Methods: Five consecutive patients with postinfarction LVA-related VT were selected for catheter ablation at Fuwai Hospital from April 2011 to October 2015 in this retrospective study. After a routine transaortic LV-mapping approach was failed, a transseptal approach with a steerable sheath was performed in all these cases. The study was approved by the Ethics Committee of Fuwai Cardiovascular Hospital (approval No. 2016-768) on May 24, 2016. Results: In these five patients, four had LVAs located in the LV apical area, and one in the septum. Acute ablation successes were all failed to achieve through the transaortic route. Two were due to aortic stenosis and tortuous peripheral arteries and the others were due to failure to target the effective sites. While all ablation procedures succeeded through the sequent transseptal approach with a steerable sheath, and no major complications related to the transseptal approach were reported. During the 12-month (10–12 months) follow-up, no electrical storm or episode of VT was documented. One VT recurrence occurred, yet acute success was obtained again through the transseptal approach. Conclusions: Transseptal approach appears a feasible, safe, and effective method in catheter ablation for VT with LVA and could be considered as an elective approach.

Keywords: Ablation, steerable sheath, transseptal approach, ventricular aneurysm, ventricular tachycardia

How to cite this article:
Chen L, Tang M, Ren X, Fang P, Zhang J, Feng T, Zhai Z, Dong X, Zhang S. Feasibility of the transseptal approach for mapping and ablation in patients with ventricular aneurysm-related ventricular tachycardia with a steerable sheath: A retrospective study. Int J Heart Rhythm 2021;6:85-9

How to cite this URL:
Chen L, Tang M, Ren X, Fang P, Zhang J, Feng T, Zhai Z, Dong X, Zhang S. Feasibility of the transseptal approach for mapping and ablation in patients with ventricular aneurysm-related ventricular tachycardia with a steerable sheath: A retrospective study. Int J Heart Rhythm [serial online] 2021 [cited 2023 Mar 21];6:85-9. Available from: https://www.ijhronline.org/text.asp?2021/6/2/85/334130

Introduction

Radiofrequency catheter ablation has been proven as an effective adjunctive therapy for scar-related ventricular tachycardia (VT) in patients with structural heart disease, especially those with implantable cardioverter-defibrillator (ICD).^[1],[2],[3] Meanwhile a few observational case reports and small researches had also shown the feasibility of VT ablation in the presence of ventricular aneurysm.^[4],[5],[6]

A retrograde transaortic approach has frequently been used during a left VT ablation. However, for patients with aortic atheroma or stenosis, artificial aortic valve, aortic aneurysm, tortuous or occlusive peripheral arteries, this approach is limited. For these patients, a transseptal approach has to be considered.^[7],[8]

Preliminary studies have shown that although a transseptal approach is an effective approach for left ventricular (LV) mapping and ablation, there is limited access to the septal regions with the use of this method.^[9] A steerable sheath might be of advantage to mapping and ablating in LV septal regions. To the best of our knowledge, there is no report regarding catheter ablation of postinfarction LV aneurysm (LVA) related VT through the transseptal approach with the use of a steerable sheath. Therefore, our retrospective study aimed to assess the feasibility and safety of a transseptal approach for LVA-related VT mapping and ablation.

Subjects and Methods

Study population

Consecutive patients with ischemic heart disease who had failed to perform LVA-related VT ablation procedure via a retrograde transaortic approach were included in Fuwai Hospital between April 2011 and October 2015. Patients who had contraindications through a retrograde transaortic approach also were included. During this period, five patients (all male, mean age 54.2 years, range 43–63 years) were enrolled. Three patients with ICD were documented multiple defibrillation device shocks for fast VT within 3 months. Two had a recorded history of incessant VTs for 3 months before electrophysiological evaluation. No ventricular thrombus was detected by transthoracic echocardiography. All these patients had a long-term amiodarone therapy before the procedure. Written informed consents were provided by all the patients. The study was approved by the Ethics Committee of Fuwai Cardiovascular Hospital (approval No. 2016-768) on May 24, 2016.

Mapping and ablation procedure

A 6F decapolar catheter (St. Jude Medical, St. Paul, MN, USA) was positioned into the coronary sinus via the right jugular vein, and a 6F quadripolar catheter (C. R. Bard, Murray Hill, NJ, USA) was inserted into the right ventricular (RV) apex through the right femoral vein. A routine transaortic approach was performed in all these patients. The patients who had contraindication or failed to ablate via the transaortic route then underwent a transseptal puncture with an 8.5F AgilisTM NxT sheath (large curl; St. Jude Medical, St. Paul, MN, USA) under fluoroscopic guidance. The first three patients had successful LV-mapping through a transaortic approach; however, all failed to target effective ablation sites due to large LVAs. A transseptal puncture was performed with an Agilis sheath. The fourth patient was found bilateral tortuous and stenotic iliac arteries. The fifth patient had right iliac artery occlusion and left iliac artery stenosis. These two patients were difficult to perform LV-mapping even after an 8.5F Swartz™ left 1 sheath (Fast-Cath™ St. Jude Medical, MN, USA) was utilized in the aorta. These two patients then also chose to perform a transseptal puncture with an Agilis sheath. During sinus rhythm, the electro-anatomical substrate LV mapping was performed using a three-dimensional CARTO mapping system (Biosense Webster, Diamond Bar, CA, USA). Mapping and ablation procedures were performed by using cool-tip ablation electrodes (Thermocool; Biosense Webster). Scarred areas were defined with an amplitude <0.5 mV. Border zones were defined with amplitudes ranging from 0.5 to 1.5 mV. Ablation lesions were obtained at the exit point of the tachycardia (corresponded to the site of earliest activation on the activation mapping) and at the isthmus of the tachycardia circuit (the border zone between the scar area and the healthy myocardium) by delivering 60 s pulsesx of radiofrequency current under thermal control (55°C, 25 W). The effectiveness of the procedure was assessed by repeating the programmed stimulation (up to three extrastimuli) and burst pacing (progressively shortened cycle length) of the RV apex. Acute success was defined as no VT induction after at least two extrastimuli by ventricular stimulation in 15 min or more after ablation.^[1],[5]

In-hospital management and follow-up

All but one patient received amiodarone intake every day after ablation. All patients were followed up every 6 months. ICD interrogation was performed during each outpatient clinical visit.

Results

Patient characteristics

Four patients had LVAs located in the LV apical area, one in the septal region. The mean LV ejection fraction was 41.2% (range 33%–57%). The mean LV end-diastolic diameter was 59.2 mm (range 54–70 mm). More detailed patient characteristics are in [Table 1].

Table 1: Characteristics of ventricular aneurysm related ventricular tachycardia patients

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Mapping and ablation

Apical and basal infero-septal regions had significantly more detailed maps through the transseptal access especially with the use of an Agilis sheath [Figure 1] and [Figure 2].

Figure 1: (a and b) Transseptal puncture and left ventricular basal inferoseptal aneurysm left ventricular aneurysm angiography in 30° right anterior oblique projection and 45° left anterior oblique projection. I and II indicate an Agilis sheath advanced through the atrial septum and the ablation catheter located at the target site, respectively. Also seen are the catheter in the coronary sinus, the pigtail catheter (III) in the left ventricular, the catheter in the right ventricular and the implantable defibrillator ventricular lead (D). (c) A large left ventricular aneurysm was at good target site. RV=Right ventricular

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Figure 2: (a–c) Transseptal puncture and a large left ventricular apical aneurysm angiography in 45° left anterior oblique projection and 30° right anterior oblique projection respectively. I and II indicate an Agilis sheath advanced through the atrial septum and the ablation catheter located at the final target. III indicates failed to locate at the effective target via a retrograde transaortic approach as ablation catheter I did via a transseptal approach. Also seen are the catheter in the coronary sinus, the catheter in the right ventricular, a pigtail catheter (P) and the implantable defibrillator ventricular lead (D). (d) Voltage map shows with purple healthy myocardium with an amplitude >1.5 mV and with red the scar with an amplitude <0.5 mV which corresponds to a large apical left ventricular aneurysm

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Twelve induced morphologies of VT (4, 1, 2, 3, 2, respectively) were mapped. Moreover, the mean VT cycle length was 449.08 ± 74.83 ms (range 324–530 ms). The mean bipolar amplitude of the target potential was 0.475 ± 0.171 mV (range 0.229–0.712 mV). The mean earliest activation preceded the QRS complex onset by 41.42 ± 9.70 ms (range 32–64 ms). Acute ablation success was achieved via the sequent transseptal approach with a steerable sheath. No more inducible VTs occured after the programmed stimulation. Mapping and ablation parameters are reported in [Table 2].

Table 2: Mapping and ablation accuracy, complications, outcomes of ventricular aneurysm related ventricular tachycardia patients

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No cardiac complications or femoral hematomas and pseudoaneurysms occurred. No steerable sheath-related complications occurred. During the 12-month follow-up, no electrical storm was documented; VT recurrence occurred in one patient at his 6-month follow-up, while acute ablation success was regained through the transseptal approach with an Agilis sheath.

Discussion

The major findings of our study were as follows: (1) A transseptal approach is an effective and safe method in mapping and ablation for patients with postinfarction LVA-related VT, and might be considered as an alternative to retrograde transaortic route; (2) with the use of a steerable sheath, mapping and ablation efficacy could be improved through a transseptal approach, especially for LVA-related VT originating from the LV apical/basal inferoseptal regions.

Catheter ablation is recommended in patients with scar-related heart disease and sustained VT, especially recurrent ICD shocks due to sustained VT or electrical storm.^[10] The traditional approach for LV-mapping and VT ablation is a retrograde transaortic approach. However, in some cases, for patients with contraindications (such as aortic stenosis, aortic aneurysm, and severe peripheral artery diseases), a transseptal approach as an alternative should be recommended. Both of these two approaches are proven to be a safe and effective method for ischemic or nonischemic VT ablation.^{[8],[9],[11],[12],[13]} In our study, two patients had contraindications (severe iliac arteries stenosis/occlusion) and failed to ablate through a transaortic route even with the help of a Swartz™ left 1 sheath in the aorta. While a transseptal approach with an Agilis sheath had worked.

Previous studies have already reported limitations both for transaortic and transseptal approaches as to the accessibility to some particular LV regions. Pluta et al.^[9] reported that there is limited access to the septal areas with the use of a transseptal approach; while the lateral wall had fewer detail maps via a transaortic route. A study by evaluating 10 patients undergoing VT ablation using contact force-sensing catheters, in which both a transseptal and a transaortic approach were performed, found that contact force was significantly higher in the mid-anteroseptum, mid-inferior, and apex segments via transseptal approach and significantly higher in the basal-anteroseptum, basal-inferoseptum, basal-inferior, and basal-lateral regions via transaortic route.^[11] Ouyang et al.^[14] reported that the anterosuperior LV outflow tract could be reached through a transseptal route with a reversed S curve of the catheter while a transaortic approach could not. For patients with LVA-related VT, besides contraindications, sometimes it is hard to target the effective sites via the transaortic approach due to a large aneurysm.

As for the limitations of the transseptal approach, especially for large LVA, maybe a manually controlled steerable sheath instead of a conventional nonsteerable Swartz sheath could be considered when the transseptal approach is used. Swartz sheath was first invented for paroxysmal supra VT ablation and could only be steadily located in some particular regions. For patients with large LVA, the use of Swartz sheath may be limited. Previous studies have compared the nonsteerable and steerable sheath in atrial fibrillation/atrial flutter ablation and concluded that the steerable sheath can improve the success rate of atrial fibrillation and atrial flutter ablation, especially in patients with severe LA enlargement.^{[15],[16],[17],[18]} In our study, three patients (two had large apical LVAs and one had basal inferoseptal LVA) were successfully performed LV mapping through the transaortic approach, while failed to identify the effective ablation targets and unable to suppress VTs. With the help of an Agilis sheath, a trend toward more detailed maps of the apical/basal inferoseptal LVA was observed and the effective target sites were easily identified via the transseptal approach. Acute successes were all finally achieved in these five patients.

In addition, our study reported one case of VT recurrence. Large LVA-related VTs have a relatively high number of redo procedures due to the following complex factors: Extensive arrhythmogenic substrate; myocardial dystrophy, fibrosis, and calcifications within the aneurysm; and epicardially located area of the critical isthmus.^[19] However, acute success was regained still through the transseptal approach with an Agilis sheath in our study.

Although the transaortic approach for left ventricle originating VT ablation remains the gold standard method, our results suggested that a transseptal approach could be a safe and feasible alternative not only for patients with contraindications but for patients with large LVA. Meanwhile, a steerable sheath could be considered during the LV mapping and ablation via the transseptal approach.

Limitations

Our study was retrospective and the population was too small. Moreover, our study did not compare the outcomes of a steerable sheath with nonsteerable sheath in LV mapping/VT ablation for patients with large LVA. However, to date, no published VT studies have reported the transseptal approach for LVA-related VT in mapping and ablation with the help of a steerable sheath. Hence, this study can be considered as a pilot only. Prospective and well-designed studies are awaited.

Conclusions

These results suggest that a transseptal approach seems to be a safe, effective, and feasible method of RF ablation for patients with LVA-related VT. Moreover, it could be considered as an important alternative to the retrograde transaortic route in patients with limitations or contraindications to the latter. What is more, the steerable sheath seems to improve the transseptal approach for mapping and ablation of the LVA-related VT originating from the LV apical/septal region. More extensive and randomized studies are needed to confirm our study.

Institutional review board statement

The study was approved by the Ethics Committee of Fuwai Cardiovascular Hospital (approval No. 2016-768) on May 24, 2016.

Declaration of patient consent

The authors certify that they have obtained all appropriate consent from patients. In the forms, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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