Tailored Ablation Strategies for Atrial Fibrillation With Common Inferior Pulmonary Vein Variants

Abstract

Background

The common inferior pulmonary vein (CIPV) is a rare anatomical variant that may complicate pulmonary vein isolation for atrial fibrillation (AF). We present tailored ablation strategies for AF patients with CIPV or CIPV-like anatomy.

Methods

Six AF patients with CIPV were retrospectively analyzed. Pre- or postprocedural computed tomography and/or three-dimensional mapping identified the anatomy. Ablation was guided by voltage mapping, with lesions delivered only at sites with electrical activity.

Results

Four patients had paroxysmal AF and 2 patients had persistent AF. The right superior and left superior pulmonary veins were isolated in all cases. CIPV was treated with limited ostial ablation (n = 4), complete trunk isolation (n = 1), or single-ring posterior wall isolation (n = 1). No acute complications occurred. Over a mean follow-up of 14.2 months, 5 of the 6 patients remained free from AF recurrence.

Conclusions

Tailored ablation strategies based on imaging and voltage guidance allow safe and effective treatment of AF in patients with CIPV.

Visual Summary

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation (AF).¹ Common inferior pulmonary vein (CIPV) variants are rare, occurring in approximately 0.5% to 1.5% of patients, and they present unique challenges to conventional PVI techniques.2, 3, 4 The CIPV variants include 2 major anatomic categories: 1) common inferior pulmonary trunk (CIPT), where both inferior pulmonary veins (PVs) fuse into a single trunk draining into the left atrial posterior wall,^2,3 and 2) confluent inferior PVs with adjacent ostia (dubbed “confluent inferior PVs”), where the right and left inferior veins have separate but adjacent ostia near the posterior left atrium (Figure 1). These distinctions are important because the ablation strategy may differ depending on morphology. Recent advancements in cardiac computed tomography (CT), magnetic resonance imaging, and three-dimensional (3D) electroanatomical mapping have improved the ability to preoperatively identify such anatomical anomalies.^3,5

Take-Home Messages

• •Preprocedural imaging is critical to recognize CIPV variants and guide ablation strategy.
• •CIPV regions are frequently electrically silent, supporting tailored, voltage-guided ablation.
• •Tailored ablation approaches are effective and safe, achieving durable rhythm control with minimal unnecessary atrial ablation.

Figure 1.

Schematics of Inferior PV Variants in the Present Series

Posteroanterior view of the left atrium is shown. (Left) Normal PV anatomy. (Center) CIPV trunk (CIPT). (Right) Confluent inferior PVs and adjacent ostia (dubbed “confluent inferior PVs”). Purple and pink areas indicate electrically active and silent lesions, respectively. CIPV = common inferior pulmonary vein; LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein; PV = pulmonary vein; RIPV = right inferior pulmonary vein; RSPV = right superior pulmonary vein.

While several reports have described the anatomical characteristics of CIPVs, their electrophysiological behavior remains less well understood. Although CIPVs often display minimal or absent electrical activity, contributing little to AF triggers, they are often targeted by ablation.^6,7 Despite the emergence of newer treatment arsenals such as cryoablation and pulsed-field ablation (PFA),^8,9 whether electrically dormant CIPVs require ablation remains an open question. In this study, we present 6 patients with AF and CIPV or CIPV-like anatomy (ie, confluent inferior PVs) treated with personalized catheter ablation strategies at our institution.

Methods

We retrospectively reviewed 6 AF patients undergoing catheter ablation at our institution (2014-2025) with CIPV or confluent inferior PVs identified by CT and/or 3D mapping.

Imaging Protocol

Preprocedural contrast-enhanced CT was obtained with 0.5- to 0.6-mm slice thickness during the pulmonary vein phase phase. Images were reconstructed on a dedicated workstation (CartoMerge, Biosense Webster).

Electrophysiological Study and Mapping

Ablation procedures were performed under conscious sedation or general anesthesia. Voltage mapping was performed using the CARTO 3 system (Biosense Webster). All maps were created during sinus rhythm after cardioversion when necessary. Low voltage was defined as bipolar amplitude <0.5 mV. Regions without discrete electrograms were classified as electrically silent.

Catheters and Energy Delivery

Except for patient 1, in which a nonirrigated, non–contact force–sensing catheter was used (Ablaze 8 mm, Japan Lifeline), an open-irrigated, contact force–sensing radiofrequency catheter (ThermoCool SmartTouch SF, Biosense Webster) was used in all patients. Because of the varied technologies available upon ablation, power settings were heterogeneous. Typical power settings were 30 to 50 W, with a contact force of 10 to 20 g. Lesions were applied for 6 seconds (posterior wall near esophagus) to approximately 30 seconds (targeting ablation index: >450) each (see Table 1 for details). Lesion sets were adjusted to esophageal proximity.

Table 1.

Clinical Characteristics, Anatomical Categories, Ablation Strategies, and Outcomes of the 6 Patients Included in This Series

	Patient 1	Patient 2	Patient 3	Patient 4	Patient 5	Patient 6
Age, y/sex	44, male	52, male	61, male	81, male	79, male	76, male
Anatomy type	CIPT	CIPT	Confluent inferior PVs	Confluent inferior PVs	Confluent inferior PVs	Confluent inferior PVs
AF type	PAF	PAF	PAF	PeAF	PAF	PeAF
Energy source	RF, nonirrigated, non–CF-sensing 8-mm tip, 30 W	RF, irrigated, CF-sensing, 30-35 W	RF, irrigated, CF-sensing, 30-35 W	RF, irrigated, CF-sensing, 30-35 W	RF, irrigated, CF-sensing, AI-guided, 50 W	RF, irrigated, CF-sensing, AI-guided, 50 W
Lesion set	RSPV and LSPV individual isolation only	Complete trunk isolation + RSPV and LSPV isolation	LSPV isolation and C-shaped RSPV isolation + CIPV region only where potentials	C-shaped isolation of both PVs + CIPV region only where potentials	C-shaped isolation of both PVs + CIPV region only where potentials	Posterior wall “box” isolation
Number of ablations targeting CIPV region	0	16 (trunk isolation)	1	10 (bottom line)	7	4
Procedure/Fluoroscopy time (min)	293/164	190/37	155/36	132/19	110/5	144/18
Complications	None	None	None	None	None	None
Follow-up and outcome	No recurrence at 120 mo	No recurrence at 24 mo	No recurrence at 12 mo	Recurred at 10 mo, managed with AADs	No recurrence at 12 mo	No recurrence at 10 mo

AAD = antiarrhythmic drug; AI = ablation index; CF = contact force; CIPT = common inferior pulmonary trunk; LSPV = left superior pulmonary vein; PAF = paroxysmal atrial fibrillation; PeAF = persistent atrial fibrillation; PV = pulmonary vein; RF = radiofrequency; RSPV = right superior pulmonary vein.

Patients were categorized as having either a CIPT or confluent inferior PVs with adjacent ostia. Radiofrequency ablation was used in all patients, with tailored energy settings: In the earlier cases, standard power (30 W) was applied on the anterior left atrium and reduced power (20-25 W) on the posterior wall, with contact force (when available) maintained at 10 to 20 g. In the more recent cases we used modern technologies such as high-power short duration (50 W) and ablation index–guided ablation. In 4 patients, ablation was limited to ostial potentials, 1 patient underwent complete CIPT isolation, and 1 patient required a posterior wall “box” isolation. Pulmonary vein entrance and exit block was achieved in all cases, with additional posterior wall bidirectional block in patient 6. No acute complications occurred. Over a mean follow-up of 14.2 months, 5 of the 6 patients remained free from atrial fibrillation recurrence.

Endpoint

PVI was confirmed by entrance and exit block. For posterior wall isolation, bidirectional block was verified.

Follow-Up

Patients underwent a standard 3-month blanking period. Monitoring included clinic visits with 12-lead electrocardiogram at 1, 3, 6, and 12 months, plus Holter monitoring at 3 to 6 months. AF recurrence was defined as any atrial tachyarrhythmia >30 seconds beyond blanking.

Results

CIPT (n = 2) or confluent inferior PVs (n = 4) were identified in all 6 patients by pre- or postprocedural CT and/or 3D mapping. The clinical and procedural characteristics are summarized in Table 1. Four patients presented with paroxysmal AF and 2 patients with persistent AF. In the present case series, it was common that electrical activity within the CIPV region was largely silent (note the red areas in the voltage maps of Figures 2, 3, 4, 5, and 6), with occasional PV potentials (example shown in Figure 2, small white arrow).

Figure 2.

Localized PV Potential Around the CIPV

(Left) Axial and 3D-reconstructed computed tomography images showing inferior PVs with adjacent ostia. (Upper Right) Pre-maps, and (Lower Right) post-maps. In addition to left superior and right superior PVs, the proximal aspect of the right inferior PV that continues to the common trunk (big white arrows) was targeted. In contrast, the low-voltage area within the CIPV was largely untouched. A small white arrow in the lower right panel indicates an ablation point within the CIPV lesion that silenced the local potential within the lower left branch of the CIPV. 3D = three-dimensional; CIPV = common inferior pulmonary vein; PV = pulmonary vein.

Figure 3.

C-Shaped Wide-Area Circumferential Lesion Set

To not only avoid ablation over electrically silent (and anatomically challenging) adjacent inferior ostia but also target the electrically anterior aspect of left and right PV antra, which were electrically active, we performed “C-shaped” wide-area circumferential ablation, resulting in postprocedural success without complications. (Top) Pre-maps and (Bottom) post-maps suggest the effectiveness of this approach. Depending on the distribution of PV potential, C-shaped ablation was performed on both sides of PVs (the current figure) or on either side (right PVs in Figure 2) on a case-by-case basis. Some points within the CIPV lesion in which PV potentials were observed were manually ablated at the operator's discretion (white arrows). CIPV = common inferior pulmonary vein; PV = pulmonary vein.

Figure 4.

Partially Intruding Electrical Activity Around the CIPT

The CARTO 3 voltage map demonstrating low-voltage zones along the posterior wall corresponding to the CIPT with electrical activity partially intruding in the middle of the CIPT (white arrows), which were respectively ablated on a point-by-point basis. As a result, the bottom line was formed (arrows).

Figure 5.

Antral Right-Sided PV Ablation Across Low-Voltage CIPV

(Upper Left) CT images demonstrate a peculiar form of CIPV (or a CIPV-like variant). (Right) Low-voltage zone across inferior PVs (or posterior aspect of CIPV) was electrically silent. In addition to individual isolation of a superior left PV, we decided to perform “antral” right PV isolation over the low-voltage continuity between both sides of the inferior PVs (arrows). (Lower Left) Fluoroscopic and 3D mapping view show selective ablation of local potentials at the CIPV ostium while sparing electrically silent tissue. 3D = three-dimensional; CIPV = common inferior pulmonary vein; CT = computed tomography; PV = pulmonary vein.

Figure 6.

Single-Ring CIPT Isolation

As described by previous research, we had a patient in which the CIPT was isolated with the box line. Trunk isolation was performed because individual superior PV isolation was not enough to suppress AF recurrence in response to high-rate atrial pacing. After trunk isolation, acute success was declared as sinus rhythm was maintained following high-rate atrial pacing. AF = atrial fibrillation; CIPT = common inferior pulmonary trunk; PV = pulmonary vein.

We designated the ablation line based on the presence or absence of PV potential within each PV. The right superior PV and left superior PV were successfully isolated in all patients, either individually 4, 5, and 6) or as a part of a “C-shaped” wide-area circumferential lesion set (Figures 2 and 3) that avoided ablation over electrically silent PV ostia. Ablation targeting the CIPV region was limited to segments with demonstrable electrical potentials in 4 patients (examples are shown in Figures 4 and 5), whereas trunk isolation was performed in 1 patient (Figure 6). One patient underwent wide-area posterior wall isolation given low voltage across the entire posterior region. No acute complications occurred. During a mean follow-up of at least 10 months, 5 of the 6 patients remained free from AF recurrence.

Discussion

Our findings support recent literature indicating that CIPV variants are rare but important to recognize.2, 3, 4 Early CT studies have documented the prevalence and morphology of CIPV variants.^2,3 More recent series have demonstrated successful ablation with radiofrequency, cryoballoon, or PFA in CIPV anatomy, with favorable outcomes.^4,8,9 Our findings align with the literature, emphasizing practical, anatomy-guided decision-making.

In most patients in the present series, AF did not recur after index ablation, even with (Figure 6) or without (Figures 2, 3, 4, and 5) extensive ablation around the CIPV region, suggesting the possibility that routine extensive ablation may not be necessary in silent CIPV. In our earlier cases, such as patient 2 (Figure 6), a trunk isolation was empirically performed because the optimal strategy for this rare anatomy was uncertain at that time. As our experience accumulated, we gradually simplified the lesion set by reducing unnecessary applications to electrically silent areas, focusing instead on a C-shaped antral line and limited spot ablation guided by local potentials. The favorable long-term outcomes with this simplified approach imply that trunk isolation may not be essential and that tailored, voltage-guided ablation targeting only active regions could be sufficient in most CIPV cases.

It is important to emphasize that the posterior aspect of the CIPT is in close proximity to the esophagus (see CT image in Figure 2). Furthermore, this part is largely electrically silent. Therefore, it appears reasonable to refrain from ablation in this area, as electrical dormancy indicates a lack of therapeutic benefit. This view is consistent with the existing literature indicating that routine empirical posterior wall isolation has not consistently shown superiority over PVI.¹⁰ The present study suggests the possibility that a tailored approach based on imaging and voltage may achieve rhythm control while avoiding unnecessary ablation.

PFA is emerging as a safer energy source for anatomically complex regions, such as the inferior common trunk, by minimizing the risk of collateral injury to the esophagus or phrenic nerve. Expansion of PFA use appears promising in these types of anatomical cases. Future studies using PFA may further validate the safety and efficacy of tailored approaches for CIPV variants.

Visual Summary.

Inferior PV Variants Are Often Electrically Silent

The present case series, which limits ablation in the region, suggests a possibility that routine, extensive ablation is not always needed. LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein; PV = pulmonary vein; RIPV = right inferior pulmonary vein; RSPV = right superior pulmonary vein.

Conclusions

In AF patients with CIPV variants, individualized ablation strategies guided by imaging and voltage appear safe and effective. Avoiding unnecessary ablation in electrically silent regions may minimize procedural risk.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.