Hybrid Surgical Ablation of Recurrent Ventricular Tachycardia in a Patient With High-Risk Brugada Syndrome.

A 38-year-old man with a diagnosis of Brugada syndrome had a recurrence of monomorphic ventricular tachycardia 6 years after successful epicardial right ventricular outflow tract ablation by the use of subxiphoid access. Preprocedural and intraprocedural investigations suggested that the pathologic substrate of the right ventricular outflow tract had not been eliminated completely. Therefore, the patient underwent a hybrid electrophysiology-guided video-assisted thoracoscopic ablation. (Level of Difficulty: Advanced.).

A 38-year-old man patient with Brugada syndrome (BrS) and a previously implanted implantable cardioverter-defibrillator (ICD) presented to our device clinic for a standard check-up.

Learning Objectives

To reduce the risk of ventricular arrhythmia recurrences in patients with Brugada syndrome.

To identify arrhythmogenic substrate precisely by using 2 different mapping systems.

To ensure complete substrate elimination and reduce the risk of damaging collateral structures.

Medical History

The patient first received a diagnosis of BrS at the age of 24 years. After confirmation of the BrS diagnosis with an ajmaline challenge, an ICD was implanted in 2007. In 2011, multiple episodes of ventricular tachycardia (VT), treated with antitachycardia pacing and intracardiac shocks, were recorded by the device in concomitance with a syncopal event. Considering the family history of sudden cardiac death, the arrhythmic syncope, and the Brugada pattern type 1 uncovered by the ajmaline test, he was considered a good candidate for an epicardial ablation of the anterior right ventricular outflow tract (RVOT) with subxyphoid percutaneous access guided by an electronatomical mapping system. No arrhythmia recurrence was noted until the last device check-up (Figure 1).

Figure 1

Case Report Timeline

Timeline of the case from first discovery of Brugada syndrome (Brs) in 2007 until most recent follow-up visit in 2021. Numbers on the lower part of the illustration are number of ventricular tachycardia/ventricular fibrillation (VT/VF) episodes during the year; ∗VT/VF followed by implantable cardioverter-defibrillator (ICD) discharge. RVOT = right ventricular outflow tract; VATS = video-assisted thoracoscopic surgery.

Investigations

Interrogation of the device showed 3 monomorphic VT episodes, which occurred respectively in 2017 and 2018, with the last one broken by an internal shock (Figure 2). The electrocardiography (ECG) findings pointed to the anterior RVOT (Figure 3). An echocardiogram, a chest x-ray, and the results of a complete blood test were unremarkable.

Figure 2

Implantable Cardioverter-Defibrillator Recording of Monomorphic Ventricular Tachycardia Episode

Documented recurrence of monomorphic ventricular tachycardia 6 years after index procedure.

Figure 3

Preoperative Electrocardiogram

Brugada pattern type 1 present on leads V1, V2.

Management

Based on the previous long-term success of the subxyphoid epicardial ablation (6 years) and the fact that the pathologic substrate of BrS is generally located in the epicardial layer, the patient was scheduled for a hybrid thoracoscopic epicardial ablation of the anterior RVOT region.

The procedure was performed with the patient under general anesthesia, with the support of a noncontact cardiac mapping system (CardioInsight) before, during, and after the procedure, and an invasive endocardial and epicardial mapping using the Ensite system (Abbott).

During the procedure, a left-sided thoracoscopy was performed, and 3 5-mm ports were installed in intercostal spaces II, IV, and VI, and 2 instrument ports and 1 camera port (Figure 4). The pericardium was opened anteriorly to the left phrenic nerve, at the level of RVOT and of the anterior side of the right ventricle (RV).

Figure 4

Left-Sided Thoracoscopy

Camera port installed in IV intercostal space, 2 functional ports installed in II and VI intercostal spaces.

Interestingly, the thoracoscopic camera allowed the operators to assess the location and entity of previous epicardial radiofrequency (RF) applications. A multipolar catheter was advanced inside the thorax through the lower port and placed on top of the RVOT (Figure 5, left).

Figure 5

Video-Assisted Thoracoscopic Ablation Procedure

(A) Multipolar grid catheter placed on the anterior right ventricular outflow tract through thoracoscopic port. (B) Ablation on the right ventricular outflow tract with use of unipolar RF ablation probe.

A noninvasive electroanatomical map was created to confirm the baseline activation pattern. Meanwhile, endocardial invasive mapping was performed using the multipolar diagnostic catheter before and after the administration of ajmaline (1 mg/kg). A Brugada type 1 pattern was uncovered. Low-voltage long fragmented potentials (FP) were also present on the entire epicardial RVOT and on the anterior epicardial wall side of the RV adjacent to the RVOT (Figures 6 and 7).

Figure 6

Slow Conduction on the Right Ventricular Outflow Tract: Fragmented Potentials

Long (104 ms), low-voltage, fragmented potentials, aligned with QRS complex, recorded with multipolar catheter placed on the anterior right ventricular outflow tract, a typical finding on patients with Brugada syndrome.

Figure 7

Preablation Invasive Mapping

Invasive epicardial activation map created using Ensite Precision System. Red areas showing earliest activation. Blue colors represent areas of slowed conduction. (Left) Baseline map showing delayed conduction over the anterior right ventricular outflow tract (RVOT). (Right) Channels B2-B3, C2-C3, D2-D3 showing long low-voltage fragmented potentials on the RVOT, typical of patients with Brugada syndrome. Postablation invasive mapping is inaccurate because impedance changes after insertion of first thoracoscopic port.

Epicardial RF was applied to eliminate these abnormal potentials. A unipolar RF probe (CoolRail, Atricure) was advanced through the lower thoracoscopic port to the area of the fractionation. RF ablation of the epicardial RVOT and of the adjacent epicardial anterior wall was performed (Figure 5, right). Mapping with a multipolar grid catheter after the ablation showed complete absence of FP on the RVOT. A left-sided sympathectomy from distal C8 to T5 was also performed because of the concomitant long QT syndrome. At the end of the procedure, the ajmaline test was repeated. Both mapping systems confirmed lack of FP, which were associated with the complete absence of Brugada type I pattern on the 12-lead ECG (Figure 8). Therefore, it was decided not to perform an endocardial part of the hybrid ablation procedure.

Figure 8

Preablation and Postablation Noninvasive Mapping

(Left) Noninvasive activation map before and after ablation. Red areas show earliest activation. Blue colors represent areas of slowed conduction. (Far left) the earliest activation is on the anterior right ventricular outflow tract (RVOT) (small red area) and lateral RVOT is characterized by slow conduction (scar from previous ablation) blue area behind the red spot. Postablation activation is homogenous with no areas of early activation or slow conduction on the RVOT. (Right) Preablation and postablation voltage maps; violet area represents scar tissue, postablation map shows completeness of lesion area on the anterior RVOT.

Discussion

We report a first case of double epicardial ablation in the same BrS patient, using 2 different techniques.

BrS is an inherited cardiac disease ed by an increased risk of ventricular tachyarrhythmias and sudden cardiac death., Many genetic variations of ion channels have been unveiled since the discovery of the syndrome in 1992.

According to both dominant depolarization and repolarization hypotheses of BrS origin, the main area with electrophysiologic changes, leading to ECG abnormalities and ventricular arrhythmias in patients with BrS, is the epicardium of the anterior wall of the RVOT., This area is characterized by low voltage prolonged FP that become more evident under the administration of sodium channel blockers.

The standard therapy for BrS patients consists of ICD implantation to prevent sudden cardiac death. More recently, a new more invasive strategy has been developed: it consists in the elimination of the above-mentioned epicardial RVOT pathologic substrate using RF ablation, with the endpoint of normalizing the ECG type 1 pattern and rendering patients with BrS uninducible for ventricular tachyarrhythmias. The first report on this topic was published by Nademanee et al in 2011. Since then, several RVOT epicardial RF ablation techniques have been described by other investigators, ranging from a percutaneous invasive approach to more invasive surgical procedures. The effectiveness of every particular technique remains debatable, and every approach should be individualized.

Percutaneous epicardial ablation was first described in 1996 by Sosa et al and has become the preferred strategy for treating a variety of cardiac dysrhythmias. This technique has fundamental differences from endocardial ablation, adding limitations to this technique because of the increased risk of damaging collateral structures while manipulating the catheter. Significant strides have been made during the past 2 decades that have improved the intraprocedural strategies of percutaneous epicardial ablation. Nevertheless, there is still a clinical need for improving the safety of epicardial access and the efficacy of energy sources to ensure complete elimination of the arrhythmogenic substrate.

This case report clearly shows that despite the short-term and mid-term success of the index ablation procedure, performed with a percutaneous technique, the long-term result was not optimal.

Therefore, the strategy of epicardial surgical RVOT ablation was used after the recurrence, using a hybrid cardiac surgery ablation approach to overcome the potential limitations of percutaneous ablation. This technique has been developed in our center, was first described by Salghetti et al, and allows direct visualization of the target region and a clear view of the surrounding anatomical structures, which makes this procedure safe as effective. The real-time monitoring of probe contact and using specific tools designed especially for VAT procedures allows the creation of wider and durable lesions with less edema and a shorter procedure time.

The hybrid approach also allows a close collaboration between the cardiac surgeon and the electrophysiologist. RVOT surgical ablation can be tailored through an invasive and noninvasive mapping, which is useful in localizing the substrate of the disease and in quantifying the extension of the ablation lesions.

Follow-Up

The patient has had no recurrence of VT/VF at the 2-year follow-up visit.

Conclusions

This is the first case of a surgical epicardial ablation in a BrS patient who had previously undergone a percutaneous epicardial ventricular tachycardia ablation. This case supports the hypothesis that the main arrhythmogenic substrate in BrS patients is located on the anterior RVOT and stresses the limitations of the percutaneous approach for epicardial substrate ablation in favor of direct visualization techniques.

Funding Support and Author Disclosures

Dr. de Asmundis has received research grants on behalf of the center from Biotronik, Medtronic, Abbott, LivaNova, Boston Scientific, AtriCure, Philips, and Acutus; and has received compensation for teaching purposes and proctoring from Medtronic, Abbott, Biotronik, Livanova, Boston Scientific, Atricure, and Acutus Medical Daiichi Sankyo. Dr. Chierchia has received compensation for teaching purposes and proctoring from Medtronic, Abbott, Biotronik, Boston Scientific, and Acutus Medical. Dr. La Meir has been a consultant for Atricure. Dr. Eltsov has received compensation from Medtronic. Dr. Monaco has reported that they have no relationships relevant to the contents of this paper to disclose.