The PFA era for persistent superior vena cava: From daunting challenge to streamlined therapy

Key Teaching Points.

• •This case demonstrates the feasibility of pulsed field ablation (PFA) for achieving both acute and durable (3-month) electrical isolation in patients with persistent left superior vena cava (PLSVC).
• •The procedure highlights the safety and efficiency of PFA in this anatomically complex scenario, with rapid isolation achieved and no observed complications such as pericardial effusion, coronary spasm, or phrenic nerve injury.
• •Using a combined approach with circular and focal contact force PFA catheters allows for adaptable and precise ablation, effectively streamlining the treatment of persistent atrial fibrillation in the presence of PLSVC.

Introduction

Persistent left superior vena cava (PLSVC) is an important but challenging arrhythmogenic source in patients with atrial fibrillation (AF).^1,2 Conventional thermal ablation techniques carry potential risks of complications, including phrenic nerve injury and cardiac tamponade, making optimal PLSVC isolation a clinical dilemma.³ Here, we present a case of successful and safe electrical isolation of the PLSVC using pulsed field ablation (PFA), a non-thermal energy modality with inherent tissue selectivity.⁴ The procedure achieved durable isolation without acute complications, highlighting PFA’s potential as a promising alternative for PLSVC ablation. This report underscores the feasibility of PFA in managing anatomically complex arrhythmogenic structures while minimizing collateral damage, paving the way for further investigation into its broader applications in AF ablation.

Case report

A 70-year-old man with persistent AF and cardiac dysfunction was referred for first-time catheter ablation. The patient had a decade-long history of hypertension, though he self-discontinued anti-hypertensive medications 3 years prior before apparent normotension. His cardiovascular risk factors included a 40-pack-year smoking history and regular alcohol consumption (30 g/day), both ceased 3 years before presentation. The arrhythmia history began 7 years prior with self-terminating paroxysmal AF episodes, progressing to persistent AF 1 year before admission despite rivaroxaban anti-coagulation. Admission electrocardiogram confirmed AF (Figure 1A), whereas transthoracic echocardiography revealed biatrial enlargement (left atrium [LA] 48 × 49 × 63 mm, right atrium 45 × 59 mm), PLSVC, dilated coronary sinus (26 mm ostium diameter), and minimal pericardial effusion, later confirmed by intra-cardiac echocardiography (ICE) (Figure 1B). Notably, left ventricular (LV) function was preserved (LV ejection fraction 65%, LV end-diastolic dimension 45 mm), and coronary computed tomography angiography excluded significant stenosis.

Figure 1.

A: Admission electrocardiogram demonstrating atrial fibrillation. B: Intra-procedural intra-cardiac echocardiography prior to ablation, showing a markedly dilated coronary sinus ostium (asterisk) and pericardial effusion.

The procedure was performed during AF rhythm following femoral venous access. A 10-Fr sheath introduced the ICE catheter, whereas a 7-Fr sheath accommodated the coronary sinus decapolar catheter. During attempted superior vena cava cannulation for transseptal puncture, the guidewire failed to advance, prompting right atrial voltage mapping with the circular PFA catheter, which confirmed the absence of the right superior vena cava (Figure 2). The transseptal puncture was ultimately achieved using combined 3-dimensional (3D) electroanatomic mapping and ICE guidance (Figure 2). Heparin was administered (3000 IU bolus pre-puncture, then 80 IU/kg) to maintain activated clotting time >300 s throughout.

Figure 2.

3D reconstruction of the right atrium and PLSVC (left panel: RAO 30°; right panel: LAO 45°). Note the absence of the right superior vena cava. Precision transseptal puncture was performed under 3D electroanatomic mapping guidance. 3D = 3-dimensional; LAO = left anterior oblique; PLSVC = persistent left superior vena cava; RAO = right anterior oblique.

The procedure used the integrated LEAD-PFA system (Jinjiang Electronic Medical Device Technology Co., Ltd), combining PFA with 3D electroanatomic mapping (LEAD-Mapping) for precise navigation.⁵ LA and pulmonary vein geometry was reconstructed using a circular PFA catheter, while ablation was performed primarily with a focal contact force PFA catheter. Pulmonary vein isolation and LA posterior wall ablation were achieved through point-by-point applications (4 biphasic pulses per site, 200 ms, 1800 V), followed by linear lesions at the mitral isthmus (Figure 3A) and cavotricuspid isthmus (Figure 3B) using the same energy settings. The circular catheter was selectively deployed for PLSVC isolation (Figure 4A), achieving complete electrical isolation within 13 minutes (6 applications, 4 pulses each) as confirmed by elimination of all local potentials (Figure 4B). Persistent AF required direct current cardioversion (200 J), with bidirectional block across all lines validated after a 20-minute waiting period (Figure 5) using established criteria⁵: (1) differential pacing for cavotricuspid isthmus block (>120 ms delay); (2) proximal-to-distal coronary sinus activation during LA appendage pacing for mitral isthmus block; and (3) entrance/exit block in the PLSVC.

Figure 3.

Procedural outcomes of PFA using a focal contact-force catheter. A: Successful circumferential pulmonary vein isolation (PVI), posterior wall isolation, and mitral isthmus ablation (left panel: LAO view; right panel: LL view). B: Complete tricuspid isthmus ablation (left panel: RAO view; right panel: INF view). INF = inferior; LAO = left anterior oblique; LL = left lateral; PFA = pulsed field ablation; RAO = right anterior oblique.

Figure 4.

Electrical isolation of PLSVC using a circular PFA catheter. A: Intra-cardiac electrograms demonstrating electrical activity within PLSVC during ablation (left panel: RAO view; right panel: PA view). B: Complete elimination of PLSVC potentials following successful ablation (left panel: LL view; right panel: PA view). LL = left lateral; PA = posteroanterior; PFA = pulsed field ablation; PLSVC = persistent left superior vena cava; RAO = right anterior oblique.

Figure 5.

Confirmation of bidirectional block across MI using differential pacing. MI block validation. A: Pacing from the left atrial appendage base (electrodes 1–2 of focal contact-force catheter, 500 ms cycle length) demonstrates proximal-to-distal coronary sinus activation sequence. B: Pacing from CS 1–2 yields a 156 ms conduction delay to the ablation line. CS = coronary sinus; MI = mitral isthmus; S-A = stimulus-to-atrial potential recorded with the ablation catheter at the lateral flank of the line.

The procedure concluded without any procedural complications, including vascular access issues, pericardial effusion (with no increase from baseline trivial amount), coronary artery spasm, or phrenic nerve injury. No thromboembolic events were observed. Post-procedural monitoring confirmed sustained sinus rhythm. After a 3-month blanking period, the patient remained asymptomatic with maintained sinus rhythm on 24-hour Holter monitoring.

Discussion

To our knowledge, this is the first report worldwide to describe the successful isolation of PLSVC using the LEAD-PFA system in a patient with persistent AF undergoing index catheter ablation. Due to the unique anatomical challenges posed by a PLSVC, conventional catheter ablation (radiofrequency or cryoballoon) carries inherent risks of complications, such as cardiac tamponade and phrenic nerve palsy when isolating this structure.^3,6 PFA, with its non-thermal mechanism of action (irreversible electroporation)⁴ and often specific catheter designs, presents a promising alternative for managing such complex anatomies.

Initial experiences with other PFA systems for PLSVC isolation have been reported. Tohoku et al⁷ first described successful PLSVC electrical isolation using a pentaspline-type PFA catheter (FARAWAVE, Boston Scientific) shaped in a basket configuration. More recently, Mizuno et al⁸ reported a case series using a circular array PFA catheter (PulseSelect, Medtronic) for PLSVC isolation, demonstrating favorable acute safety and feasibility outcomes. These preliminary reports highlight the potential advantages of PFA, including procedural safety, ease of use, and short-term efficacy in this context.

The circular ablation catheter of the LEAD-PFA system shares a similar circular array design with the PulseSelect catheter. However, the LEAD-PFA catheter features a smaller diameter (15 mm vs 25 mm),^8,9 which may enhance its flexibility and navigability within the PLSVC. Crucially, the LEAD-PFA catheter offers independent deflection capabilities, allowing for precise directional control and optimal tissue contact beyond what is achievable solely via sheath manipulation. This feature is particularly advantageous for effective ablation at the critical left atrium-PLSVC interface. Furthermore, unlike the previously reported cases which relied on the CARTO3 system (Biosense Webster) for 3D mapping while performing catheter manipulation and ablation under fluoroscopic guidance, the LEAD-PFA system integrates the PFA generator with a proprietary 3D electroanatomic mapping and magnetic navigation system (LEAD-Mapping).⁵ This integrated platform enables a completely fluoroless procedure after transseptal puncture, encompassing catheter navigation, mapping, and ablation. Additionally, the impedance-sensing capability of the LEAD-PFA circular catheter provides real-time contact feedback, and its built-in pulse circuit self-checking technology, which prevents discharge under unsafe impedance conditions (eg, too low or too high), may contribute to enhanced ablation reliability and a reduced risk of complications such as hemolysis.

Given the limited sample size (a single case) and short follow-up duration in our report, the findings should be interpreted as preliminary, highlighting early feasibility, and acute safety. This case demonstrates the potential of the LEAD-PFA system, particularly its circular catheter, for safe and effective PLSVC isolation. Larger prospective studies with longer-term follow-up are warranted to validate the efficacy, lesion durability, and optimal ablation protocol for this specific application.

Conclusion

This case demonstrates the versatility of the LEAD-PFA system. Besides being capable of 3D electroanatomical modeling of the heart, the focal contact force catheter’s stability enabled durable linear ablation, while the circular catheter’s design optimized PLSVC isolation—addressing anatomical challenges unmet by the single-catheter strategy.

Disclosures

The authors have no conflicts of interest to disclose.