Incidence and predictors of stroke and silent cerebral embolism following very high-power short-duration atrial fibrillation ablation

Atrial fibrillation-related ischemic stroke and cognitive impairment: Research progress on the characteristics and pathogenesis

Post-stroke cognitive impairment (PSCI) is a significant neurological complication, affecting up to one-third of stroke survivors. Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia, significantly increasing the risk of ischemic stroke. Increasing evidence suggests that AF plays a pivotal role in exacerbating cognitive decline in stroke patients. This review integrates current clinical, imaging, and mechanistic findings to elucidate how AF-related strokes exacerbate cognitive decline through multiple overlapping pathways, including thromboembolism, neuroinflammation, atherosclerosis, cerebral hypoperfusion, cerebral small vessel disease, and silent infarctions. These processes collectively impair cerebrovascular integrity, induce neuronal damage, and accelerate brain aging. The review further evaluates the role of clinical and neuroimaging biomarkers as predictive tools and their utility in guiding therapeutic strategies. By integrating insights of the latest researches, we aim to provide a comprehensive framework for alleviating cognitive decline in patients with AF-related stroke and highlight future research directions.

Char Formation During Very High-Power Short-Duration Ablation for Atrial Fibrillation

INTRODUCTION

Pulmonary vein (PV) isolation using very high-power short-duration (vHPSD) radiofrequency catheter ablation is an effective treatment strategy for atrial fibrillation. However, PV isolation using vHPSD ablation (vHPSD-PVI) carries a potential risk of char formation. We aimed to assess the incidence, patient characteristics, and procedural factors of char formation during vHPSD-PVI.

METHODS AND RESULTS

Fifty consecutive patients scheduled to undergo initial PV isolation (PVI) were prospectively included. PVI was performed using a QDOT MICROTM catheter in the vHPSD setting (90 W/4 s). PVs were divided into eight segments, and char formation around the ablation catheter was evaluated after the ablation of each segment. Patient characteristics and procedural parameters were analyzed to determine the risk factors for char formation. During vHPSD-PVI, char formation was observed in 24 (48.0%) patients, primarily at the groove between the tip and ring electrodes. Among the segments, the incidence of char formation was the highest (26.0%) in the anterior and posterior right inferior PV (RIPV) segments (p < 0.001). One patient with char formation developed symptomatic thromboembolism after the procedure. The left atrial volume index (LAVI) (odds ratio [OR], 1.089; 95% confidence interval [CI], 1.011-1.173; p = 0.024) and parallel catheter orientation (OR, 1.592; 95% CI, 1.416-1.791; p < 0.001) were independent predictors of char formation.

CONCLUSION

Char formation occurred in 48.0% of the patients during vHPSD-PVI. Application to the RIPV segment, a higher LAVI, and parallel catheter orientation were associated with an increased risk of char formation, indicating that vHPSD applications should be avoided under these conditions.

Comparative analysis of therapeutic strategies in atrial fibrillation patients with left atrial appendage thrombus despite optimal NOAC therapy

BACKGROUND AND AIMS

Left atrial appendage (LAA) thrombus is the primary cause of stroke and systemic embolism in atrial fibrillation (AF). Non-vitamin-K oral anticoagulants (NOACs) effectively reduce LAA thrombus prevalence and stroke risk. However, the optimal treatment of a NOAC-resistant thrombus remains unclear. We aimed to evaluate therapeutic strategies for resolving LAA thrombus in patients on optimal NOAC therapy.

METHODS

We retrospectively analyzed patients scheduled for cardioversion or catheter ablation of AF between 2014 and 2023 with LAA thrombus on transesophageal echocardiography (TEE) despite being on optimal NOAC therapy. We assessed how the applied management strategy affected thrombus resolution.

RESULTS

Among the analyzed 120 patients, a change to a different NOAC occurred in 41% of cases, a transition to a VKA in 30%, and the supplementation with antiplatelet therapy in 11%. In contrast, 18% of the patients received unchanged therapy. Follow-up imaging at 65 [44 - 95] days showed successful thrombus resolution in 92 (77%) of cases, predicted by a lower CHA2DS2-VASc score (p = 0.01). Any modification of antithrombotic therapy was an independent predictor of thrombus resolution (OR 5.28 [1.55-18], p = 0.01). Of the four strategies, there was a trend toward better thrombus resolution with switching to a VKA (OR 3.23 [1.03-10.1], p = 0.04).

CONCLUSION

Resolution of LAA thrombus in patients already on adequate NOAC treatment may require a revision of the anticoagulation strategy. In addition, transitioning from NOAC to VKA might be considered.

Cerebral Safety Comparison: High-Power vs. Low-Power Ablation in AF Pulmonary Vein Isolation

BACKGROUND

The use of high-power short-duration radiofrequency ablation techniques for atrial fibrillation (AF) treatment has gained popularity; however, the implications for cerebral safety, particularly regarding the risk of silent cerebral embolism (SCE), remain unclear. This study aims to assess procedural complications, focusing on cerebral safety, between HPSD and LPLD ablation techniques in patients who are receiving pulmonary vein isolation for AF.

METHODS

This study comprised 74 patients who were randomly allocated into two equal groups at a 1:1 ratio. The HPSD group utilized a 70 W, whereas the LPLD group employed a 40 W. The study evaluated safety (asymptomatic cerebral embolism, bleeding, and steam pop incidence) and efficacy (ablation time and success rates) between the groups.

RESULTS

In the HPSD group, 9 (26%) patients experienced SCE, compared to 12 (33%) patients in the LPLD group. The two groups did not differ significantly (p = 0.482). There were no clinically evident cerebrovascular events (stroke or TIA) in any patients. The incidence of steam pops was comparable (5% vs. 3%, p = 0.556). Significant differences were observed in ablation times for the left (218.70 ± 96.48 vs. 600.27 ± 249.83 s, p < 0.001) and right pulmonary veins (224.05 ± 77.89 vs. 658.38 ± 168.84 s, p < 0.001). A single case of hematoma was reported in the LPLD group.

CONCLUSIONS

The incidence of SCE during PVI ablation is similar between HPSD and LPLD techniques. HPSD ablation is a safe and effective technique that significantly reduces ablation time without elevating perioperative complications.

Clinical and subclinical acute brain injury caused by invasive cardiovascular procedures

Over the past 50 years, the number and invasiveness of percutaneous cardiovascular procedures globally have increased substantially. However, cardiovascular interventions are inherently associated with a risk of acute brain injury, both periprocedurally and postprocedurally, which impairs medical outcomes and increases health-care costs. Current international clinical guidelines generally do not cover the area of acute brain injury related to cardiovascular invasive procedures. In this international Consensus Statement, we compile the available knowledge (including data on prevalence, pathophysiology, risk factors, clinical presentation and management) to formulate consensus recommendations on the prevention, diagnosis and treatment of acute brain injury caused by cardiovascular interventions. We also identify knowledge gaps and possible future directions in clinical research into acute brain injury related to cardiovascular interventions.

Clinical impact of very high-power-short-duration catheters on biomarkers after atrial fibrillation ablation

Background

Very high-power short-duration (vHPSD) catheters are associated with less irrigation fluid load than standard (STD RF) ablation catheters. However, the impact of this fluid reduction on biomarkers in pulmonary vein isolation (PVI) for atrial fibrillation (AF) remains unknown.

Methods and Aim

Biomarkers of heart failure, myocardial injury, and systemic inflammation status as Brain Natriuretic Peptide (BNP), high-sensitivity Troponin I (hsTnI), and C-reactive protein (CRP) were collected pre- and post-procedure of PVI for symptomatic AF. The study aimed to assess the impact of vHPSD catheter compared to an STD catheter (respectively irrigation of 8 vs. 15 mL/min during ablation) on biomarker alterations.

Results

The study included 83 consecutive patients (59 males [71.1%], mean age 62.6 ± 11 years), with vHPSD catheters used in 53 cases (63.9%). No significant baseline differences were observed between groups.Fluid irrigation resulted in significantly lower with vHPSD catheter than STD RF (434.8 ± 105.6 vs. 806.6 ± 256.5 mL, p < .001). Correspondingly, BNP variation was significantly lower in the vHPSD group than in the STD RF group, both in absolute change (12 [IQR -9-47] pg/mL vs. 44.5 [IQR 21-88.7] pg/mL, p = .002) and percentage change (16.3 [IQR -13.2-108.6] % vs. 84.1 [IQR 32.5-172.1] %, p = .012). When considering absolute values, a statistically significant increase in BNP was found only in the STD catheter group (from 52 [IQR 35.2-113.5] to 113 [IQR 66.7-189.5] pg/mL, p < .001), whereas no significant increase was observed in the vHPSD group (p = .06). CRP levels increased post-PVI in both groups, but the delta was significantly lower in the vHPSD group (p = .025). No significant differences in post-procedural hsTnI were detected between groups.

Conclusion

The use of a vHPSD catheter is associated with reduced fluid irrigation and a correspondingly smaller increase in BNP, a biomarker indicative of fluid overload and heart failure.

High-power short-duration setting prevents changes of periprocedural thrombotic markers and the onset of silent stroke in patients with atrial fibrillation

Background

It remains unclear whether the newly adopted high-power, short-duration (HP-SD) setting in ablation for atrial fibrillation (AF) impacts periprocedural thrombotic markers or silent stroke (SS) onset.

Objective

The aim of the present study was to investigate the clinical impact of HP-SD setting ablation on changes in periprocedural thrombotic markers and the onset of SS.

Methods

We enrolled 101 AF patients: the HP-SD group (n = 67) using 50 W and the conventional ablation group (n = 34) using 30 to 40 W. D-dimer, thrombin-antithrombin complex (TAT), and total plasminogen activator inhibitor-1 (tPAI-1) were analyzed the day before, immediately after, and 1 day after the procedure. Magnetic resonance imaging was performed within 48 hours after the procedure.

Results

Left atrial dwelling time was significantly shorter in the HP-SD group (P < .05). In the conventional ablation group, the D-dimer and tPAI-1 levels continued to increase until 1 day postprocedure, while the TAT peaked immediately after the ablation. On the other hand, the range of the variation of these thrombotic markers in the HP-SD group was smaller. SS occurred more frequently in the conventional ablation group than in the HP-SD group (26% vs 5%, P < .05). In the logistic regression analysis, the HP-SD setting and TAT difference (postprocedure - preprocedure) were independent predictors for SS (odds ratios 0.141 and 5.838, respectively; P < .05).

Conclusions

The HP-SD setting led to a shorter left atrial dwelling time and reduced change in thrombotic markers, resulting in lower prevalence of SS.

Catheter ablation for atrial fibrillation: indications and future perspective

Recent advances in techniques, technologies and proven superiority over anti-arrhythmic drugs have made catheter ablation the cornerstone of management for atrial fibrillation (AF), which has shown a steady increase in prevalence in the ageing population worldwide. The aim of therapeutic interventions is to achieve stable sinus rhythm that would improve the quality of life and reduce the risk of AF-associated complications. Pulmonary veins (PVs) were first described as the source of initiation of ectopic triggers driving AF, which led to the establishment of PV isolation (PVI) as the most widely practiced procedure to treat AF. Antral PVI is still recognized as the stand-alone ablation strategy for newly diagnosed paroxysmal AF (PAF). However, in non-PAF patients, PVI seems to be inadequate and several adjunctive strategies, including ablation of left atrial posterior wall and non-PV triggers, AF mapping and ablation of rotors and drivers, ethanol infusion of vein of Marshall and renal denervation, etc. have been reported with mixed results. Recent trials have also documented the benefits of early rhythm control in preventing cardiovascular events in addition to slowing the progression of PAF to more persistent forms. Similarly, very late relapse of the arrhythmia after successful PVI has drawn attention to the critical role of non-PV triggers and highlighted their relevance as potential ablation targets during repeat procedures. Ablation technology is also under constant evolution with the introduction of non-thermal energy sources and new tools to create durable lesions. This review summarizes the indications, advancements, and future perspective of AF ablation.

Comparison of cerebral safety after atrial fibrillation using pulsed field and thermal ablation: Results of the neurological assessment subgroup in the ADVENT trial

BACKGROUND

Atrial fibrillation (AF) ablation carries the risk of silent cerebral event (SCE) and silent cerebral lesion (SCL). Although "silent," these may have long-term clinical implications and are challenging to study as postprocedural magnetic resonance imaging (MRI) is not standard of care.

OBJECTIVE

The neurological assessment subgroup (NAS) of ADVENT compared cerebral effects of pulsed field ablation (PFA) with standard-of-care thermal ablation.

METHODS

The NAS included consecutive randomized PFA and thermal ablation patients who received postprocedural brain MRI 12-48 hours after ablation. Patients with apparent SCE or SCL findings underwent a modified Rankin scale assessment. MRI images were subsequently reviewed by a blinded brain imaging core laboratory.

RESULTS

In total, 77 patients with paroxysmal AF were enrolled at 6 centers; 71 had analyzable scans (34 PFA; 37 thermal ablation). Through individual center review, 6 PFA and 4 thermal scans were identified as SCE/SCL positive, of which 3 PFA and 0 thermal SCE/SCL findings were confirmed by a blinded core laboratory. MRI findings revealed 1 patient with 2- to 4-mm SCEs, 1 patient with a 3-mm SCE, and 1 patient with 2 SCLs (5.5 mm and 11 mm). All modified Rankin scale and National Institutes of Health Stroke Scale scores were 0 before discharge and at 90-day follow-up. There were only 2 neurological safety events (1 transient ischemic attack [PFA] and 1 stroke [thermal ablation]) in the ADVENT study, neither of which was part of the NAS.

CONCLUSION

The ADVENT trial provides the first prospective, randomized data on the cerebral impact of PFA and thermal ablation of AF. Incidence of SCE/SCL after ablation in the NAS was low.

Microembolizations in the arterial cerebral circulation during atrial fibrillation ablation: cryoballoon technique advantages and neurocognitive safety-results of a prospective observational study

AIMS

The significance of micro-embolic signals (MESs) during atrial fibrillation (AF) ablation is unclear. Previous studies had limitations, and cryoballoon (CB) ablation patients were under-represented. Minimizing MESs is recommended due to their uncertain neurocognitive impact.

METHODS AND RESULTS

This prospective observational study included AF patients from a German centre between February 2021 and August 2022. Patients were equally divided into paroxysmal (Group A) and persistent (Group B) AF. Group A received cryoballoon-pulmonary vein isolation only, while Group B also had left atrial roof ablation. MESs were detected using transcranial Doppler ultrasonography during ablation. Neurocognitive status was assessed pre- and post-procedure and at 3 months using the CERAD Plus battery. The study analyzed 100 patients with a median age of 65.5 years. A total of 19 698 MESs were observed, with 80% being gaseous and 20% solid in origin, primarily occurring during pulmonary vein angiography and the balloon freeze and thawing phase. The median MES per patient was 130 (IQR: 92-256) in total, 298 (IQR: 177-413) in bilateral (36%), and 110 (IQR: 71-130) in unilateral (64%) recordings. No significant difference in total MES counts was found between the groups. None of the 11 neuropsychological tests showed cognitive decline post-procedure or at 3 months.

CONCLUSION

Our observations confirm that neurocognitive abilities are not affected either 24 h or 3 months after AF ablation using the CB technique. However, despite the low MES burden associated with the CB, more work is needed to reduce small embolic events during AF ablation.

Evaluation of microembolic signals on carotid ultrasound during pulmonary vein isolation with high-power short-duration and cryoballoon ablations: When and where do bubble and solid emboli arise?

INTRODUCTION

The underlying risks of asymptomatic embolization during high-power short-duration (HPSD) ablation for atrial fibrillation remain unclear. We aimed to evaluate microembolic signals (MESs) during HPSD ablation with power settings of 50 and 90 W in comparison with those during cryoballoon (CB) ablation using a novel carotid ultrasound-Doppler system that classifies solid and air bubble signals using real-time monitoring.

METHODS AND RESULTS

Forty-seven patients underwent HPSD ablation using radiofrequency (RF), and 13 underwent CB ablation. MESs were evaluated using a novel pastable soft ultrasound probe equipped with a carotid ultrasound during pulmonary vein isolation. We compared the detailed MESs and their timing between RF and CB ablations. The number of MESs and solid signals were significantly higher in the RF group than in CB group (209 ± 229 vs. 79 ± 32, p = .047, and 83 ± 89 vs. 28 ± 17, p = .032, respectively). In RF ablation, the number of MESs, solid, and bubble signals per ablation point, or per second, was significantly higher at 90 W than at 50 W ablation. The MESs, solid, and bubble signals were detected more frequently in the bottom and anterior walls of the left pulmonary vein (LPV) ablation. In contrast, many MESs were observed before the first CB application and decreased chronologically as the procedure progressed. Signals were more prevalent during the CB interval rather than during the freezing time. Among the 28 patients, 4 exhibited a high-intensity area on postbrain magnetic resonance imaging (MRI). The MRI-positive group showed a trend of larger signal sizes than did the MRI-negative group.

CONCLUSION

The number of MESs was higher in the HPSD RF group than in the CB group, with this risk being more pronounced in the 90 W ablation group. The primary detection site was the anterior wall of the LPV in RF and the first interval in CB ablation.

Initial clinical experience with the balloon-in-basket pulsed field ablation system: acute results of the VOLT CE mark feasibility study

AIMS

Pulsed field ablation (PFA) for the treatment of atrial fibrillation (AF) potentially offers improved safety and procedural efficiencies compared with thermal ablation. Opportunities remain to improve effective circumferential lesion delivery, safety, and workflow of first-generation PFA systems. In this study, we aim to evaluate the initial clinical experience with a balloon-in-basket, 3D integrated PFA system with a purpose-built form factor for pulmonary vein (PV) isolation.

METHODS AND RESULTS

The VOLT CE Mark Study is a pre-market, prospective, multi-centre, single-arm study to evaluate the safety and effectiveness of the Volt™ PFA system for the treatment of paroxysmal (PAF) or persistent AF (PersAF). Feasibility sub-study subjects underwent phrenic nerve evaluation, endoscopy, chest computed tomography, and cerebral magnetic resonance imaging. Study endpoints were the rate of primary serious adverse event within 7 days and acute procedural effectiveness. A total of 32 subjects (age 61.6 ± 9.6 years, 65.6% male, 84.4% PAF) were enrolled and treated in the feasibility sub-study and completed a 30-day follow-up. Acute effectiveness was achieved in 99.2% (127/128) of treated PVs (96.9% of subjects, 31/32) with 23.8 ± 4.2 PFA applications/subject. Procedure, fluoroscopy, LA dwell, and transpired ablation times were 124.6 ± 28.1, 19.8 ± 8.9, 53.0 ± 21.0, and 48.0 ± 19.9 min, respectively. Systematic assessments of initial safety revealed no phrenic nerve injury, pulmonary vein stenosis, or oesophageal lesions causally related to the PFA system and three subjects with silent cerebral lesions (9.4%). There were no primary serious adverse events.

CONCLUSION

The initial clinical use of the Volt PFA System demonstrates acute safety and effectiveness in the treatment of symptomatic, drug refractory AF.