A quantitative comparison of left- versus right-atrial intracardiac echocardiography for pulmonary vein visualization: a prospective single-center study

Background

Intracardiac echocardiography (ICE) enables real-time visualization of cardiac structures during catheter ablation. In pulsed field ablation (PFA), optimal catheter–tissue contact is helpful and can be assessed with ICE. Conventional right atrial (RA) ICE may provide suboptimal visualization of pulmonary veins (PVs), while left atrial (LA) ICE may offer superior delineation. However, quantitative comparisons between RA-ICE and LA-ICE are lacking.

Purpose

To quantitatively compare pulmonary vein visualization between RA-ICE and LA-ICE and to derive patient factors influencing PV visualization by ICE.

Methods

In this prospective single-center study, 49 consecutive patients undergoing initial PFA for atrial fibrillation were enrolled. Before ablation, an ICE catheter was positioned sequentially in the RA and LA. Each PV visualization (left superior: LS, left inferior: LI, right superior: RS, right inferior: RI) was graded using a 4-point scale: 4 = Excellent: clear visualization of PV antrum, ostium, and distal segment, 3 = Good: antrum and ostium visible, distal segment not visualized, 2 = Poor: antrum visible, ostium barely visualized, 1 = Very Poor: antrum visible, ostium not visualized (figure1). Adequate visualization was defined as Excellent/Good. Paired comparisons were performed using the Wilcoxon signed-rank test and patient factors associated with each PV visualization by RA-ICE were analyzed using ordinal logistic regression analysis.

Results

Mean age was 72 ± 10 years, 59% were male. PV visualization was consistently better with LA-ICE compared with RA-ICE (figure 2). For the LSPV, mean scores were 2.0 ± 0.7 with RA-ICE versus 3.6 ± 0.7 with LA-ICE (p < 0.001). The LIPV showed 2.6 ± 0.8 versus 3.5 ± 0.7 (p < 0.001). The RSPV was particularly poorly visualized with RA-ICE (1.8 ± 0.8) compared with LA-ICE (4.0 ± 0.2, p < 0.001), and RIPV showed 2.5 ± 0.8 versus 3.9 ± 0.3 (p < 0.001). LA-ICE achieved adequate visualization in nearly all PVs, while RA-ICE frequently failed. Ordinal logistic regression demonstrated that left atrial volume index (LAVI) significantly affected RA-ICE visualization of the left superior PV (p = 0.015), with larger left atrial volume associated with lower visualization scores. No significant association was observed for the other PVs (LI, RS, RI).

Total procedure time was 96 ± 26 minutes, and total PFA time was 31 ± 9 minutes. No procedure-related complications occurred.

Conclusion

Left atrial ICE provides significantly better pulmonary vein visualization compared with conventional right atrial imaging. Left atrial enlargement negatively affects RA-ICE visualization of the LSPV.