Silent cerebral lesions following catheter ablation for atrial fibrillation: a state-of-the-art review

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.

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.

Pulsed Field Ablation of Atrial Fibrillation: A Novel Technology for Safer and Faster Ablation

Atrial fibrillation (AF), the most common arrhythmia, is associated with increased morbidity, mortality, and healthcare costs. Evidence indicates that rhythm control offers superior cardiovascular outcomes compared to rate control, especially when initiated early after the diagnosis of AF. Catheter ablation remains the single best therapy for AF; however, it is not free from severe complications and only a small percentage of AF patients in the Western world ultimately receive ablation. Ensuring that AF ablation is safe, effective, and efficient is essential to make it accessible to all patients. With the limitations of traditional thermal ablative energies, pulsed field ablation (PFA) has emerged as a novel non-thermal energy source. PFA targets irreversible electroporation of cardiomyocytes to achieve cell death without damaging adjacent structures. Through its capability to create rapid, selective lesions in myocytes, PFA presents a promising alternative, offering enhanced safety, reduced procedural times, and comparable, if not superior, efficacy to thermal energies. The surge of new evidence makes it challenging to stay updated and understand the possibilities and challenges of PFA. This review aims to summarize the most significant advantages of PFA and how this has translated to the clinical arena, where four different catheters have received CE-market approval for AF ablation. Further research is needed to explore whether adding new ablation targets, previously avoided due to risks associated with thermal energies, to pulmonary vein isolation can improve the efficacy of AF ablation. It also remains to see whether a class effect exists or if different PFA technologies can yield distinct clinical outcomes given that the optimization of PFA parameters has largely been empirical.

Considerations regarding safety with pulsed field ablation for atrial fibrillation

The introduction of pulsed field ablation (PFA) in electrophysiology marks a significant advancement, promising efficacy comparable to thermal ablation methods while potentially providing safety advantages. Despite a generally favorable safety profile in human trials and postmarket registries, cautious evaluation of PFA's safety is essential. This review provides a comprehensive overview of key safety considerations as we discuss a myriad of considerations ranging from thermal effects, gaseous microbubble formation, muscle contractions, and proarrhythmia to procedural techniques. We explore specific safety concerns with phrenic nerve injury, cerebral lesions, coronary artery spasm, hemolysis and pulmonary bleeding. Vigilance in safety monitoring, coupled with advancements in procedural techniques and understanding of PFA's unique effects, is crucial for optimizing the safe and effective use of PFA.

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.

Ablation Strategies for Persistent Atrial Fibrillation: Beyond the Pulmonary Veins

Despite advances in ablative therapies, outcomes remain less favorable for persistent atrial fibrillation often due to presence of non-pulmonary vein triggers and abnormal atrial substrates. This review highlights advances in ablation technologies and notable scientific literature on clinical outcomes associated with pursuing adjunctive ablation targets and substrate modification during persistent atrial fibrillation ablation, while also highlighting notable future directions.

Meta-analysis of Pulsed Field Ablation Versus Thermal Ablation for Pulmonary Vein Isolation in AF: A Broad Overview Focusing on Efficacy, Safety and Outcomes

The recently established non-thermal, single-shot pulsed field ablation (PFA) is a potential tool for achieving rapid pulmonary vein isolation (PVI) to cause cell death by electroporation, yet data regarding this state-of-the-art technology remain sparse. In this meta-analysis, we included 3,857 patients from 20 studies. There was no significant difference in AF recurrence between the PFA and control groups. Subgroup analysis showed that additional ablation beyond PVI has a similar rate of AF recurrence to PVI alone (10% versus 13%, respectively). PVI durability was achieved in 83% (mean), 95% CI [65-99%] of the PFA group and in 79% (mean), 95% CI [60-98%] of the control group, with no significant difference in the rate of PVI durability between the two groups. The PFA group had considerably reduced procedure duration, but not fluoroscopy time. No statistically significant differences in periprocedural complications were observed. PFA is associated with shorter procedural time than thermal ablation. Cardiac complications were uncommon and mainly reversible in both the PFA and control groups.

Efficacy and safety of pulsed field ablation for accessory pathways: a pilot study

AIMS

Radiofrequency ablation is used as a first-line therapy for accessory pathways (APs). However, data regarding the effects of pulsed field ablation (PFA) on APs are limited. We sought to evaluate the acute procedural and 6-month success and safety of PFA in a cohort of patients with APs.

METHODS AND RESULTS

A focal contact force-sensing PFA catheter was used for patients with APs. Pulsed field ablation generator generated a bipolar and biphasic waveform (±1000 V) with a duration of 100 ms from the tip of the PFA catheter. A 100% acute procedural success was achieved in 10 conscious patients with APs (7 left anterolateral, 2 left inferolateral, and 1 right posteroseptal APs) including 6 (60%) patients after an initial application. The average total ablation time was 6.3 ± 4.9 s for 4.7 ± 1.8 ablation sites (ASs), including 3.1 ± 2.4 s at targets and 3.2 ± 2.9 s at 3.2 ± 2 bolus ASs. The mean skin-to-skin time was 59.3 ± 15.5 min, and PFA catheter dwell time was 29.4 ± 7.8 min. One patient encountered transient sinus arrest during PFA due to parasympathetic overexcitation. Sinus rhythm was restored in all patients without any significant adverse events during the short-term follow-up.

CONCLUSION

Pulsed field ablation of APs was feasible, effective, and safe. Its efficiency was remarkable for its ultrarapid termination of AP conduction. Further studies are warranted to prove whether utilization of PFA with current parameters can extend to manifold AP ablation.

First-in-human clinical series of a novel conformable large-lattice pulsed field ablation catheter for pulmonary vein isolation

AIMS

Pulsed field ablation (PFA) has significant advantages over conventional thermal ablation of atrial fibrillation (AF). This first-in-human, single-arm trial to treat paroxysmal AF (PAF) assessed the efficiency, safety, pulmonary vein isolation (PVI) durability and one-year clinical effectiveness of an 8 Fr, large-lattice, conformable single-shot PFA catheter together with a dedicated electroanatomical mapping system.

METHODS AND RESULTS

After rendering the PV anatomy, the PFA catheter delivered monopolar, biphasic pulse trains (5-6 s per application; ∼4 applications per PV). Three waveforms were tested: PULSE1, PULSE2, and PULSE3. Follow-up included ECGs, Holters at 6 and 12 months, and symptomatic and scheduled transtelephonic monitoring. The primary and secondary efficacy endpoints were acute PVI and post-blanking atrial arrhythmia recurrence, respectively. Invasive remapping was conducted ∼75 days post-ablation. At three centres, PVI was performed by five operators in 85 patients using PULSE1 (n = 30), PULSE2 (n = 20), and PULSE3 (n = 35). Acute PVI was achieved in 100% of PVs using 3.9 ± 1.4 PFA applications per PV. Overall procedure, transpired ablation, PFA catheter dwell and fluoroscopy times were 56.5 ± 21.6, 10.0 ± 6.0, 19.1 ± 9.3, and 5.7 ± 3.9 min, respectively. No pre-defined primary safety events occurred. Upon remapping, PVI durability was 90% and 99% on a per-vein basis for the total and PULSE3 cohort, respectively. The Kaplan-Meier estimate of one-year freedom from atrial arrhythmias was 81.8% (95% CI 70.2-89.2%) for the total, and 100% (95% CI 80.6-100%) for the PULSE3 cohort.

CONCLUSION

Pulmonary vein isolation (PVI) utilizing a conformable single-shot PFA catheter to treat PAF was efficient, safe, and effective, with durable lesions demonstrated upon remapping.

Pulsed electric field, cryoballoon, and radiofrequency for paroxysmal atrial fibrillation ablation: a propensity score-matched comparison

AIMS

Pulsed field ablation (PFA) has emerged as a novel, non-thermal energy source to selectively ablate cardiac tissue. We describe a multicentre experience on pulmonary vein isolation (PVI) via the pentaspline Farapulse™ PFA system vs. thermal-based technologies in a propensity score-matched population of paroxysmal atrial fibrillation (PAF) patients.

METHODS AND RESULTS

Propensity score matching was adopted to compare PVI-only ablation outcomes via the Farawave™ system (Group PFA), cryoballoon (Group CRYO), or focal radiofrequency (Group RF) (PFA:CRYO:RF ratio = 1:2:2). Among 1572 (mean age: 62.4 ± 11.3 years; 42.5% females) PAF patients undergoing first time PVI with either PFA (n = 174), CRYO (n = 655), or RF (n = 743), propensity score matching yielded 174 PFA, 348 CRYO, and 348 RF patients. First-pass isolation was achieved in 98.8% of pulmonary veins (PVs) with PFA, 81.5% with CRYO, and 73.1% with RF (P < 0.001). Procedural and dwell times were significantly shorter with PFA, whereas the availability of a 3D mapping system led to a significant reduction in X-ray exposure with RF. Overall complication rates were 3.4% (n = 6) with PFA, 8.6% (n = 30) with CRYO, and 5.5% (n = 19) with RF (P = 0.052). The 1-year Kaplan-Meier estimated freedom from any atrial tachyarrhythmia was 79.3% with PFA, 74.7% with CRYO, and 72.4% with RF (log-rank P-value: 0.24). Among 145 repeat ablation procedures, PV reconnection rate was 19.1% after PFA, 27.5% after CRYO, and 34.8% after RF (P = 0.01).

CONCLUSION

Pulsed field ablation contributed to significantly shorter procedural times. Follow-up data showed a similar arrhythmia freedom, although a higher rate of PV reconnection was documented in post-CRYO and post-RF redo procedures.

Very-high-power Short-duration Ablation versus Conventional Ablation for Pulmonary Vein Isolation in Atrial Fibrillation: Systematic Review and Meta-analysis

The aim of this study was to compare the effectiveness and safety of very-high-power short-duration (VHPSD) ablation (70-90 W/4-7 s) with conventional ablation (30-40 W/>20 s, 50 W/7-11 s) for pulmonary vein isolation (PVI) in patients with AF. A total of 13 studies were included in this analysis (1,527 patients). AF recurrence occurred in 14% (95% CI [11-18%]) of the VHPSD group. VHPSD was associated with lower AF recurrence (OR 0.65; 95% CI [0.48-0.89]; p=0.006) compared with the conventional ablation group. Subgroup analysis showed that additional ablation beyond PVI had a similar rate of AF recurrence (16% versus 10%) compared with PVI alone. Procedure and ablation durations were significantly shorter in the VHPSD group with a mean differences of -14.4 minutes (p=0.017) and -14.1 minutes (p<0.001), respectively. Complications occurred in 6% (95% CI [3-9%]) of the VHPSD group, and the rate was similar between the two groups (OR 1.03; 95% CI [0.60-1.80]; p=0.498). VHPSD ablation resulted in less AF recurrence and a shorter procedure time. Additional ablation beyond PVI alone in VHPSD may not provide additional benefits.

Detection of brain lesions after catheter ablation depends on imaging criteria: insights from AXAFA-AFNET 5 trial

AIMS

Left atrial catheter ablation is well established in patients with symptomatic atrial fibrillation (AF) but associated with risk of embolism to the brain. The present analysis aims to assess the impact of diffusion-weighted imaging (DWI) slice thickness on the rate of magnetic resonance imaging (MRI)-detected ischaemic brain lesions after ablation.

METHODS AND RESULTS

AXAFA-AFNET 5 trial (NCT02227550) participants underwent MRI using high-resolution (hr) DWI (slice thickness: 2.5-3 mm) and standard DWI (slice thickness: 5-6 mm) within 3-48 h after ablation. In 321 patients with analysable brain MRI (mean age 64 years, 33% female, median CHA2DS2-VASc 2), hrDWI detected at least one acute brain lesion in 84 (26.2%) patients and standard DWI in 60 (18.7%; P < 0.01) patients. High-resolution diffusion-weighted imaging detected more lesions compared to standard DWI (165 vs. 104; P < 0.01). The degree of agreement for lesion confirmation using hrDWI vs. standard DWI was substantial (κ = 0769). Comparing the proportion of DWI-detected lesions, lesion distribution, and total lesion volume per patient, there was no difference in the cohort of participants undergoing MRI at 1.5 T (n = 52) vs. 3 T (n = 269).

CONCLUSION

The pre-specified AXAFA-AFNET 5 sub-analysis revealed significantly increased rates of MRI-detected acute brain lesions using hrDWI instead of standard DWI in AF patients undergoing ablation. In comparison to DWI slice thickness, MRI field strength had a no significant impact in the trial. Comparing the varying rates of ablation-related MRI-detected brain lesions across previous studies has to consider these technical parameters. Future studies should use hrDWI, as feasibility was demonstrated in the multicentre AXAFA-AFNET 5 trial.

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

AIMS

Cerebral thrombo-embolism is a dreaded complication of pulmonary vein isolation (PVI) for atrial fibrillation; its surrogate, silent cerebral embolism (SCE) can be detected by diffusion-weighted brain magnetic resonance imaging (bMRI). Initial investigations have raised a concern that very high-power, short-duration (vHPSD; 90 W/4 s) temperature-controlled PVI with the QDOT Micro catheter may be associated with a higher incidence of SCE compared with low-power long-duration ablation. We aimed to assess the incidence of procedural complications of vHPSD PVI with an emphasis on cerebral safety.

METHODS AND RESULTS

We enrolled 328 consecutive patients undergoing their PVI procedure using vHPSD. A subgroup of 61 consecutive patients underwent diffusion-weighted bMRI within 24 h of the procedure, and incidence and predictors of SCE were studied. The mean procedure time and left atrial dwell time for the overall cohort were 69.6 ± 24.1 and 46.5 ± 21.5 min, respectively. First-pass isolation was achieved in 82%. No stroke or transient ischaemic attack occurred. Silent cerebral embolism was identified in 5 of 61 patients (8.2%). Silent cerebral embolism following procedures was significantly associated with lower baseline generator impedance (105.8 vs. 112.6 Ω, P < 0.0001) and with intermittent loss of catheter-tissue contact during ablation (14.1% vs. 6.1%, P < 0.0001).

CONCLUSION

Very high-power, short-duration PVI is a safe technique with an excellent acute success rate. Silent cerebral embolism incidence in our cohort was below the previously reported range, with no clinically overt cerebral complications. Lower baseline generator impedance and loss of contact during ablation may contribute to a higher risk of SCEs.

Sudden Hearing Loss and Vertigo With Silent Pontine Infarction: A Case Report

Most cases of sudden sensorineural hearing loss (SSNHL) occur without a specific identifiable cause, although vascular factors may serve as potential etiological contributors. Silent infarction refers to ischemic changes observed on imaging studies without accompanying clinical symptoms; however, this condition is clinically significant owing to the increased risk of future stroke. We report a case of left-sided SSNHL accompanied by dizziness in a 62-year-old male patient who was diagnosed with left pontine infarction without any other neurological symptoms. The cochlea and pons receive blood supply from the anterior inferior cerebellar artery; the cochlea lacks collateral vessels and is therefore susceptible to fluctuations in blood flow. This case report provides evidence to support the vascular hypothesis as the etiology underlying SSNHL.

Implementation and first outcomes of a novel standard operating procedure for preprocedural transoesophageal echocardiography screening in course of atrial arrhythmia ablation

AIMS

Preprocedural transoesophageal echocardiography (TEE) screening for left atrial (LA) thrombi is the standard of care in many centres performing atrial fibrillation (AF) ablation. However, TEE imposes procedural risks for patients and is often challenging to implement in daily practice, besides causing patient discomfort. At our centre, a novel standard operating procedure (SOP) was implemented, aiming to identify patients that can be exempt from TEE screening. We aimed to assess whether this screening approach may reduce preprocedural TEEs without imposing patients of higher risks for cerebrovascular events (CVEs).

METHODS AND RESULTS

Data of 1874 consecutive patients treated by catheter ablation of LA arrhythmias between 2018 and 2022 were retrospectively analysed. A cohort of 937 patients, where decision to perform TEE screening was based on a new SOP (considering rhythm at admission, CHA2DS2-VASc score, and sufficient anticoagulation), was compared to a matched cohort receiving TEE before every procedure. Number of performed TEEs and incidences of CVEs were compared. Implementation of the new SOP led to a 67% reduction in TEEs performed (old SOP: 933 vs. new SOP: 305). No significant differences between the groups were detected regarding transitory ischaemic attack (old SOP: 5 vs. new SOP: 3; P = 0.48) and stroke (no events). No solid thrombi were detected during TEE screening.

CONCLUSION

The number of preprocedural screening TEEs before AF ablation procedures can be safely reduced by applying risk stratification based on rhythm at admission and CHA2DS2-VASc score, if anticoagulation was performed properly.