Wall thickness-based adjustment of ablation index improves efficacy of pulmonary vein isolation in atrial fibrillation: Real-time assessment by intracardiac echocardiography

Clinical and electrophysiological significance of residual unipolar voltage after performing pulmonary vein isolation in patients with paroxysmal atrial fibrillation

Background

Pulmonary vein isolation (PVI) is the cornerstone strategy for paroxysmal atrial fibrillation (AF). Creating a transmural block line between pulmonary vein (PV) and left atrium (LA) is important for the risk of AF recurrence. Recently, emerging evidence indicates that endocardial unipolar voltage delineates lesions of intramural or epicardial substrate in patients with ventricular tachycardia (VT). However, there are few studies on unipolar voltage evaluation in the atrium. This study describes the clinical and electrophysiological significance of unipolar voltage mapping at the site of PV-LA conjunction after PVI in patients with paroxysmal AF.

Methods

Data from patients presenting for AF ablation from April 2023 to January 2024 at Tottori University Hospital were prospectively included. To assess the electrical isolation, high-resolution voltage mapping was performed comparing groups with and without residual unipolar voltage at the site of cryo-balloon application.

Results

Fifty-seven consecutive patients who underwent cryo-balloon ablation for paroxysmal AF were included in this study. Of these, residual unipolar voltage at the site of PV-LA conjunction after PVI was identified in 22 patients. Patients with residual unipolar voltage after PVI showed significantly thicker left atrial wall thickness and larger epicardial adipose tissue volume compared with patients without residual unipolar voltage after PVI. During follow-up periods, patients with residual unipolar voltage after PVI showed a higher AF recurrence rate than those without unipolar voltage.

Conclusions

Residual unipolar voltage at the site of PV-LA conjunction after PVI may be related to AF recurrence early after the ablation, suggesting the non-transmural block line between PV and LA.

Impact of sodium-glucose cotransporter 2 inhibitors on catheter ablation for atrial fibrillation in heart failure patients without type-2 diabetes

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2is) reportedly decreased the new-onset atrial arrhythmias in patients with type-2 diabetes (T2DM) or heart failure (HF). This study examined the impact of SGLT2is on catheter ablation for atrial fibrillation (AF) in HF patients without T2DM.

METHODS

Persistent AF (PeAF) and HF (N-terminal prohormone of brain natriuretic peptide, NT-proBNP ≥400 pg/ml) patients without T2DM undergoing catheter ablation were prospectively enrolled (n = 102). SGLT2is were prescribed from ≥1 month prior to the procedure and were continued during the follow-up in 51 patients (SGLT2i[+]) but not prescribed in 51 patients (SGLT2i[-]). Left atrial pressure (LAP) was measured via the sheath placed in the LA before starting catheter ablation. The event-free rate of early and 1-year atrial-arrhythmia recurrence were compared between SGLT2i[+] and SGLT2i[-].

RESULTS

There was no significant difference in baseline characteristics between SGLT2i[+] and SGLT2i[-]. SGLT2i[+] significantly decreased average LAP compared to SGLT2i[-] (9.3 ± 4.8 mmHg vs. 12.1 ± 6.6 mmHg, p < 0.01); normalized LAP to systemic blood pressure also decreased in SGLT2i[+] (0.11 ± 0.05 vs. 0.15 ± 0.07, p < 0.01). The serum NT-proBNP levels at the enrollment were unchanged between the two groups but SGLT2i[+] had lower values on the day of catheter ablation (p = 0.06) and at 1 month after the procedure (p < 0.01) than SGLT2i[-]. SGLT2i[+] had significantly higher event-free rate of early (92 % vs. 60 %, p < 0.01) and 1-year (89 % vs. 75 %, p < 0.05) atrial-arrhythmia recurrence than SGLT2i[-].

CONCLUSION

Periprocedural SGLT2i treatment decreased LAP and improved the outcomes of catheter ablation for PeAF in HF patients without T2DM.

Impact of fat on the left atrial roof identified using intracardiac echocardiography during pulmonary vein isolation procedures

Background

Previous studies have reported the presence of fat between the septopulmonary bundle and the septoatrial bundle on the left atrial (LA) roof. This fat may increase the wall thickness and protect the septopulmonary bundle from radiofrequency energy, potentially leading to conduction gaps.

Objective

This study aimed to determine whether fat on the LA roof can be identified using intracardiac echocardiography (ICE) and whether its presence affects the procedural outcomes of pulmonary vein isolation (PVI).

Methods

We evaluated 94 patients undergoing first-time radiofrequency catheter ablation for atrial fibrillation (60 men [63.8%]; mean age 65.7±10.7 years; 46 with paroxysmal atrial fibrillation [48.9%]) between February 2021 and September 2023. ICE was used to visualize the LA roof, and hypoechoic regions suggestive of fat were marked within the CARTOSOUND map (Biosense Webster, Irvine, CA). PVI was then performed with a personalized isolation line, avoiding fat regions when feasible.

Results

Fat on the LA roof was identified in 35 of 94 patients (37.2%). Conduction gaps on the left pulmonary vein roof were observed in 7 of 35 patients with fat (20.0%) and 1 of 59 patients without fat (1.7%) (P=.004). Among patients with conduction gaps, 7 of 8 (87.5%) had a PVI line that crossed a fat region. No significant differences were noted in conduction gaps in other areas between the 2 groups.

Conclusion

The findings indicate that the presence of fat on the LA roof, as identified using ICE, may be associated with a higher incidence of conduction gaps after PVI.

Using computed tomography atrial myocardial thickness maps in cryoballoon pulmonary vein isolation: the UTMOST AF II randomized clinical trial

AIMS

Whether adjusting the duration of ablation based on left atrial wall thickness (LAWT) provides extra benefits for pulmonary vein (PV) isolation for atrial fibrillation (AF) is uncertain. We studied the safety and efficacy of tailored cryoballoon PV isolation (CB-PVI) based on LAWT for paroxysmal AF.

METHODS AND RESULTS

Two hundred seventy-seven patients with paroxysmal AF refractory to anti-arrhythmic drug were randomized 1:1 to either LAWT-guided CB-PVI (n = 135) and empirical CB-PVI (n = 142). Empirical CB-PVI was performed using a 28 mm cryoballoon with recommended application for 240 s per ablation. Cryoapplication in the LAWT-guided group was titrated (additional application for 120 s at PVs, where >25% of the circumference includes segments with LAWT > 2.5 mm and reduced baseline application to 180 s at PVs where >75% of the circumference includes segments with LAWT < 1.5 mm) according to the computed tomography LAWT colour map. The primary endpoint was freedom from any documented atrial arrhythmia of more than 30 s without antiarrhythmic medication, after a single ablation procedure. During a mean follow-up of 18.7 months, patients in the LAWT-guided CB-PVI group (70.8%) had a higher event-free rate from primary endpoint than those in the empirical CB-PVI group (54.4%; hazard ratio 0.64, 95% confidence interval 0.42-0.99; P = 0.043). No differences were observed between the groups in complication rates (3.0% in LAWT-guided vs. 4.9% in empirical CB-PVI). The total procedure time was extended in the LAWT group than in the empirical group (mean 70.2 vs. 65.2 min, respectively).

CONCLUSION

The LAWT-guided energy titration strategy improved freedom from atrial arrhythmia recurrence, compared with conventional strategy.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society.

The use of Intracardiac Echocardiography in Catheter Ablation of Atrial Fibrillation

PURPOSE OF THE REVIEW

Intracardiac echocardiography (ICE) provides real-time, fluoroless imaging of cardiac structures, allowing optimal catheter positioning and energy delivery during ablation procedures. This review summarizes the use of ICE in catheter ablation of atrial fibrillation (AF).

RECENT FINDINGS

Growing evidence suggests that the use of ICE improves procedural safety and facilitates radiofrequency and cryoballoon AF ablation. ICE-guided catheter ablation is associated with reduced procedural duration and fluoroscopy use. Recent studies have examined the role of ICE in guiding novel ablation techniques, such as pulsed field ablation. Finally, the use of ICE allows for early detection and timely management of potentially serious procedural complications. Intracardiac echocardiography offers significant advantages during AF ablation procedures and its use should be encouraged to improve procedural safety and efficacy.

Impact of different energy sources on coagulation biomarkers and silent cerebral events in balloon-based ablation for atrial fibrillation

Background

Different energy sources of balloon-based ablation for pulmonary vein isolation cause different kinds of endothelial damage and coagulation responses associated with thromboembolic risk.

Objectives

The study sought to compare the impact of different balloon-based ablation, cryoballoon ablation (CBA) and laser balloon ablation (LBA), on coagulation/fibrinolysis biomarkers and silent cerebral events (SCEs) in paroxysmal atrial fibrillation.

Methods

Paroxysmal atrial fibrillation patients who underwent pulmonary vein isolation using either CBA (n = 52) or LBA (n = 53) without radiofrequency touch-up ablation were eligible. Time course (day 0 [before ablation], day 1, day 2, and day 28) of myocardial enzymes and inflammatory and coagulation/fibrinolysis biomarkers was evaluated during the perioperative period. Brain magnetic resonance imaging was performed within 2 days after the procedure to evaluate SCEs.

Results

There was no difference in patient characteristics between CBA and LBA.CBA had greater myocardial injury (troponin I and creatine kinase-MB) and lower inflammatory reaction (white blood cell count and neutrophil/lymphocyte ratio) than LBA. The coagulation biomarkers maximally increased by day 2 and then decreased in both groups. In day 28, the serum prothrombin fragment 1+2 and D-dimer levels in LBA were significantly higher than the values in CBA. The fibrinolysis biomarker (plasmin-α2 plasmin inhibitor complex) did not increase after the procedure in either group. The incidence of SCEs was comparable between CBA and LBA (11% vs 15%; P = .591). No thromboembolic event was observed.

Conclusion

CBA and LBA had different effects on myocardial injury, inflammatory reaction, and coagulation activity but did not affect the incidence of thromboembolic events. LBA had significantly higher coagulation activity in day 28 and may require more careful postprocedural anticoagulation than CBA.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

Using computed tomogram atrial myocardial thickness maps in high-power short-duration radiofrequency pulmonary vein isolation: UTMOST AF

Background

High-power short-duration (HPSD) ablation creates wide, shallow lesions using radiofrequency (RF) heating. It is uncertain if adjusting RF energy based on atrial wall thickness provides extra benefits. We studied the safety and effectiveness of tailored HPSD energy based on left atrial (LA) wall thickness (LAWT) for circumferential pulmonary vein isolation (CPVI) in patients with paroxysmal atrial fibrillation (PAF).

Methods

We enrolled 212 patients (68.4% male, mean age: 59.5 ± 11.0 years) and randomly assigned them to two groups: LAWT-guided CPVI (WT, n = 108) and conventional CPVI (control, n = 104). Both groups used an open irrigated-tip deflectable catheter to apply 50 W for 10 s to the posterior LA, while controls used 60 W for 15 s on other LA regions. RF delivery time in WT was titrated (15 s at LAWT > 2.1 mm, 13 s at 1.4-2.1 mm, and 11 s at <1.4 mm) according to the computed tomogram-myocardial thickness color map.

Results

After a mean follow-up of 13.4 ± 7.0 months, the WT and control groups showed no significant difference regarding clinical recurrence rate (13.9% vs. 5.8%, respectively; p = .061) and major complication rate (4.6% vs. 3.8%, respectively; p > .999). The total procedure time, cardioversion rate, and post-procedural AAD prescription rates did not significantly differ between the groups.

Conclusions

The LAWT-guided energy titration strategy did not result in improved procedural safety and efficacy compared to the conventional 50-60 W-HPSD CPVI in patients with PAF.

Association of left atrial wall thickness with recurrence after cryoballoon ablation of paroxysmal atrial fibrillation

BACKGROUND

Transmural injury plays a role in successful atrial fibrillation ablation. The effect of left atrial wall thickness (LAWT) on the efficacy of radiofrequency ablation has been identified, but data on the relationship between LAWT and cryoballoon for paroxysmal atrial fibrillation (PAF) are lacking. We aim to explore the relationship between LAWT and recurrence after cryoballoon ablation (CBA).

METHODS

We studied 364 patients (mean age 62 years) with PAF who underwent a second-generation CBA and pre-procedure cardiac CTA. LAWT and left atrial volume index (LAVI) were obtained based on pre-procedure cardiac CTA measurements. Follow-up was at least 12 months and predictors of atrial tachyarrhythmia recurrence during follow-up were assessed.

RESULTS

Patients were followed up for a median of 19 (12-28) months, with an atrial tachyarrhythmia-free rate of 77.5% after cryoablation. Greater LAVI (50.0 ± 19.6 mL/m2 vs. 44.3 ± 15.4 mL/m2, P = 0.018) and greater LAWT (1.67 ± 0.24 vs. 1.46 ± 0.25 mm, P < 0.001) were associated with atrial tachyarrhythmia recurrence. The mean LAWT of PV antrum correlated with TTI (R = 0.252, P < 0.001). Adding LAWT to the established risk model improved both the discrimination and reclassification effects (IDI: 0.099, 95% CI: 0.065-0.134, P < 0.001; NRI: 0.685, 95% CI: 0.455-0.915, P < 0.001). In a multivariable Cox proportional hazard model, the mean LAWT of PV antrum (hazard ratio [HR]:3.657, 95%CI: 2.319-5.765, P < 0.001) was an independent predictor of atrial tachyarrhythmia recurrence after cryoablation.

CONCLUSIONS

The mean LAWT of PV antrum, obtained from preoperative measurements on CT, was associated with atrial tachyarrhythmia recurrence after cryoablation.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Radiofrequency lesion formation prediction with contact force versus local impedance

PURPOSE OF REVIEW

Safe and effective radiofrequency (RF) myocardial ablation requires real-time monitoring of lesion formation. Here, we review conventional and novel approaches proposed to guide titration of RF energy application.

RECENT FINDINGS

Conventional monitoring modalities, such as ablation electrode temperature, generator impedance, and tissue electrophysiological properties have been of limited value in predicting efficacy and safety of ablation. Therefore, several input-driven indices have been proposed to improve the quality and durability of RF ablation lesion while maintaining safety. These metrics predominantly incorporate RF power output, duration of RF application, and firmness and stability of electrode-tissue contact. More recently, novel catheters have enabled measuring local impedance at the catheter-tissue interface, which has been found valuable for real-time monitoring of RF lesion formation.

SUMMARY

It is likely that using the combination of multiple metrics would be required to improve the quality and safety of RF lesions, but further investigation is still required.

Tailored ablation index based on left atrial wall thickness assessed by computed tomography for pulmonary vein isolation in patients with atrial fibrillation

INTRODUCTION

Although left atrial wall thickness (LAWT) is known to be varied, a fixed target Ablation Index (AI) based pulmonary vein isolation (PVI) has been suggested in catheter ablation for atrial fibrillation (AF). We aimed to evaluate the efficacy and safety of PVI applying tailored AI based on LAWT assessed by cardiac computed tomography (CT).

METHODS

The thick segment was defined as the segment including ≥LAWT grade 3 (≥1.5 mm). The fixed AI strategy was defined as AI targets were 450 on the anterior/roof segments and 350 on the posterior/inferior/carina segments regardless of LAWT. The tailored AI strategy consisted of AI increasing the targets to 500 on the anterior/roof segments and to 400 on the posterior/inferior/carina segments when ablating the thick segment. After PVI, acute pulmonary vein (PV) reconnection, defined by the composite of residual potential and early reconnection, was evaluated.

RESULTS

A total of 156 patients (paroxysmal AF 72%) were consecutively included (86 for the fixed AI group and 70 for the tailored AI group). The tailored AI group showed a significantly lower rate of segments with acute PV reconnection than the fixed AI group (8% vs. 5%, p = .007). The tailored AI group showed a trend for shorter ablation time for PVI. One-year AF/atrial tachycardia free survival rate was similar in two groups (87.2% in the fixed AI group and 90.0% in the tailored AI group, p = .606).

CONCLUSION

Applying tailored AI based on the LAWT was a feasible and effective strategy to reduce acute PV reconnection after PVI.

Effect of pulmonary vein isolation on rotor/multiple wavelet dynamics in persistent atrial fibrillation, association with vagal response and implications for adjunctive ablation

Persistent atrial fibrillation (PeAF) may develop arrhythmogenic substrates of rotors/multiple wavelets. However, the ways in which pulmonary vein isolation (PVI) affects the dynamics of rotor/multiple wavelets in PeAF patients remain elusive. Real-time phase-mapping (ExTRa mapping, EXT) in the whole left atrium (LA) was performed during PeAF before and after PVI (n = 111). The percentage of time in which rotor/multiple wavelets (phase singularities) was observed during each 5-s phase-mapping recording (non-passive activation ratio, %NP) was measured as an index of its burden. The mapping areas showing %NP ≥ 50% were defined as rotor/multiple-wavelet substrates (RSs). Before PVI, RSs were globally distributed in the LA. After PVI, %NP decreased (< 50%) in many RSs (PVI-modifiable RSs) but remained high (≥ 50%) in some RSs, especially localized in the anterior/septum/inferior regions (PVI-unmodifiable RSs, 2.3 ± 1.0 areas/patient). Before PVI, vagal response (VR) to high-frequency stimulation was observed in 23% of RSs, especially localized in the inferior region. VR disappearance after PVI was more frequently observed in PVI-modifiable RSs (79%) than in PVI-unmodifiable RSs (55%, p < 0.05), suggesting that PVI affects autonomic nerve activities and rotor/multiple wavelet dynamics. PVI-unmodifiable RSs were adjunctively ablated in 104 patients. The 1-year AT/AF-free survival rate was 70% in those with PVI alone (n = 115), and 86% in patients with the adjunctive ablation (log-rank test = 7.65, p < 0.01). PVI suppresses not only ectopic firing but also rotor/multiple wavelets partly via modification of autonomic nerve activities. The adjunctive ablation of PVI-unmodifiable RSs improved the outcome in PeAF patients and might be a novel ablation strategy beyond PVI.

Real-time visualization of the esophagus and left atrial posterior wall by intra-left atrial echocardiography

PURPOSE

Localization of the esophagus and the left atrium (LA) posterior wall thickness (LAPWT) should be taken into account when delivering radiofrequency energy. To validate the visualization of the esophagus and analyze LAPWT by ICE advanced into the LA in patients with atrial fibrillation (AF) undergoing ablation index (AI)-guided pulmonary vein (PV) isolation.

METHODS

In 73 patients (mean age, 68 ± 12; paroxysmal AF in 45), a 3-dimensional (3D) esophagus image was created with CARTO Soundstar^Ⓡ and its location was compared with contrast esophagography saved in Carto UNIVU™. LAPWT adjacent to the esophagus was measured at 4 levels: left superior PV (LSPV), intervenous carina (IC), left inferior PV (LIPV), and LIPV bottom. A target AI value was 260 (25 W power) on the esophagus demonstrated by ICE.

RESULTS

All patients had the esophagus posterior to the left PV antrum. Creating a 3D esophagus and measurement of LAPWT with ICE was done without any complications. ICE esophagus image was completely overlapped with contrast esophagography. LAPWT (mm) was 2.8 (interquartile range, 2.5-3.2), 2.2 (1.9-2.5), 1.9 (1.8-2.1), and 2.1 (1.9-2.4) for LSPV, IC, LIPV, and LIPV bottom, respectively, while LA roof thickness was 3.2 (2.9-3.6) (P < 0.0001 by ANOVA). No residual conduction gap on the esophagus after the first circumferential PV isolation was found in 64 of 73 (88%) patients.

CONCLUSIONS

ICE inserted into the LA can reliably locate and display the esophagus and its relationship to the LA. LAPWT was the thinnest at the LIPV level. AI-guided ablation targeting at AI value 260 on the esophagus seemed to be effective.

INtra-procedural ultraSound Imaging for DEtermination of atrial wall thickness and acute tissue changes after isolation of the pulmonary veins with radiofrequency, cryoballoon or laser balloon energy: the INSIDE PVs study

Preliminary data in human suggest that both Intracardiac echocardiography (ICE) and Intravascular ultrasound (IVUS) can be used for real-time information on the left atrial (LA) wall thickness and on the acute tissue changes produced by energy delivery. This pilot study was conducted to compare ICE and IVUS for real-time LA wall imaging and assessment of acute tissue changes produced by radiofrequency (RF), cryo and laser catheter ablation. Patients scheduled for RF, cryoballoon or laser balloon Pulmonary Vein Isolation (PVI) catheter ablation were enrolled. Each pulmonary vein (PV) was imaged before and immediately after ablation with either ICE or IVUS. The performance of ICE and IVUS for imaging were compared. Pre- and post-ablation measurements (lumen and vessel diameters, areas and sphericity indexes, wall thickness and muscular sleeve thickness) were taken at the level of each PV ostium. A total of 48 PVs in 12 patients were imaged before and after ablation. Both ICE and IVUS showed acute tissue changes. Compared to IVUS, ICE showed higher imaging quality and inter-observer reproducibility of the PV measurements obtained. Acute wall thickening suggestive of oedema was observed after RF treatment (p = 0.003) and laser treatment (p = 0.003) but not after cryoablation (p = 0.69). Our pilot study suggests that ICE might be preferable to IVUS for LA wall thickness imaging at the LA-PV junctions during ablation. Ablation causes acute wall thickening when using RF or laser energy, but not cryoenergy delivery. Larger studies are needed to confirm these preliminary findings.