BACKGROUND:A limitation of ablation for scar-related ventricular tachycardia (VT) is insufficient lesion depth to address nonendocardial substrate. Ultra-low temperature cryoablation (ULTC) at -196°C has been shown to create transmural lesions in preclinical models. Early human studies in Europe have shown safety and efficacy. METHODS:An EFS (Early Feasibility Study) was designed in collaboration with the Food and Drug Administration as a prospective, nonrandomized evaluation of the acute safety and effectiveness of ULTC ablation for scar-related VT. RESULTS:Twenty patients (age 63±14 years; 5% women; LVEF 36±13%; 45% ischemic and 55% nonischemic) underwent VT ablation with ULTC from September to December 2023 at 4 clinical sites. Ablation strategies included substrate modification during sinus rhythm, as well as activation and entrainment mapping when hemodynamics permitted. Mean ULTC lesions were 9.9±3.6, with a total freeze duration of 47±22 minutes. Noninducibility of the targeted VTs was observed in 13 of 14 patients with inducibility tested both pre- and postablation. There were no procedural strokes, tamponades, or deaths. One suspected cardiac perforation without tamponade was conservatively managed. One patient was excluded from the follow-up efficacy analysis due to RF use, and another lacked postacute follow-up due to death from heart failure 1 month post-procedure. Among surviving per-protocol patients, 23.7±4.3 weeks of freedom from VT and implantable cardioverter defibrillator shock were 61.1% (11/18) and 83.3% (15/18), respectively. CONCLUSIONS:In a US EFS, ULTC therapy was safe and effective for the treatment of scar-related VT. The EFS design, in collaboration with the Food and Drug Administration, represents an important initiative to accelerate the evaluation of new medical technologies in the United States. REGISTRATION:URL: https://www.clinicaltrials.gov; Unique identifier: NCT05675865.

Background Catheter ablation procedures with transseptal punctures (usually for atrial fibrillation) are often associated with migraine-related visual auras, but the mechanism remains unknown. Whether this phenomenon is mediated by the creation of an atrial septal defect from transseptal puncture or by silent acute brain emboli detected on magnetic resonance imaging related to the procedure remains to be investigated. Objective This study aimed to evaluate whether randomization to a transseptal puncture during catheter ablation for ventricular arrhythmias is associated with postprocedural visual auras and assess the relationship between occipital and parietal lobes acute brain emboli and migraine-related visual auras. Methods In the Transseptal Versus Retrograde Aortic Ventricular Entry to Reduce Systemic Emboli trial, patients undergoing catheter ablation for ventricular arrhythmias were randomized to ventricular access via transseptal puncture vs a retrograde aortic approach. All had brain magnetic resonance imaging the day after their procedure and underwent a validated migraine assessment at 1 month. Results No differences in postablation visual auras were observed between transseptal (16% of 63) and retrograde aortic approaches (14% of 57; P = .78). However, more participants with acute brain emboli in the occipital or parietal lobes experienced migraine-related visual auras (38% vs 11%; P < .01). After multivariable adjustment, the presence of acute brain emboli was associated with 12-fold greater odds of visual auras. Conclusion Transseptal puncture was not associated with visual auras; however, acute brain emboli involving the visual cortex were associated with such symptoms. These data suggest that transseptal puncture is not causal in migraine-related visual auras and that postprocedure acute brain emboli are apparently not always clinically silent.

Background There is no established imaging technique to detect and diagnose periaortic scar, an increasingly prevalent and challenging substrate referred for ventricular tachycardia (VT) ablation. We hypothesized that wall thinning detected with intracardiac echocardiography (ICE) can identify periaortic arrhythmogenic substrate (PAS) in patients with structural heart disease. Objectives This study sought to validate a new method of identifying PAS using ICE in comparison with electro-anatomic mapping and cardiac magnetic resonance (CMR). Methods A total of 84 VT ablation patients were analyzed (87% male, median age 72 years [Q1-Q3 63-75 years], 61% with nonischemic cardiomyopathy) and categorized into 2 groups PAS+ (n = 29) and PAS- (n = 55) based on voltage-defined scar and deceleration zones. Wall thickness of the basal anterior septum was measured by ICE and CMR at a standardized distance from the left ventricular ostium in diastole by an independent core lab. In 43 patients with CMR, correlation with late gadolinium enhancement (LGE) in the basal anterior septum was also assessed. Results A significant difference in wall thickness measured at 1 cm from the left ventricular ostium with ICE was observed between PAS+ and PAS- patients (0.57 cm [Q1-Q3 0.51-0.65 cm] vs 0.72 cm [Q1-Q3 0.65-0.79 cm]; P < 0.001). Wall thickness by ICE had higher diagnostic performance than CMR, with only 50% of PAS+ patients exhibiting LGE. At a cutoff of <0.60 cm, the sensitivity and specificity of ICE predicting PAS+ were 58% and 87% (positive predictive value 71%, negative predictive value 80%) in comparison with 50% and 84% (positive predictive value 69%, negative predictive value 70%) with CMR-LGE, respectively. Conclusions ICE-detected wall thinning may be a novel imaging technique to identify arrhythmogenic periaortic VT substrate in this challenging anatomic region, which often eludes diagnosis with CMR. The absence of LGE on CMR does not rule out the presence of periaortic substrate in patients presenting with outflow tract VT.

BACKGROUND:Catheter ablation of ventricular arrhythmias, one of the most rapidly growing procedures in cardiac electrophysiology, is associated with magnetic resonance imaging-detected brain lesions in more than half of cases. Although a retrograde aortic approach is conventional, modern tools enable entry through a transseptal approach that may avoid embolization of debris from the arterial system. We sought to test the hypothesis that a transseptal puncture would mitigate brain injury compared with a retrograde aortic approach.METHODS:The TRAVERSE trial (Transseptal Versus Retrograde Aortic Ventricular Entry to Reduce Systemic Emboli) was a multicenter randomized controlled comparative effectiveness trial. Patients with left ventricular arrhythmias undergoing catheter ablation procedures were randomly assigned to a transseptal puncture approach compared (1:1) with a retrograde aortic approach. The primary outcome was the presence of an acute brain lesion detected by magnetic resonance imaging. Secondary outcomes included clinically manifest complications, procedural efficacy, and 6-month neurocognitive assessments.RESULTS:Among the 62 patients randomly assigned to a retrograde aortic approach with postoperative brain magnetic resonance imaging, 28 (45%) exhibited an acute brain lesion compared with 19 of the 69 (28%) of those randomized to a transseptal puncture (P=0.036). No differences in clinically manifest complications or procedural efficacy were observed. More patients in the retrograde aortic arm were categorized as having a high likelihood of cognitive impairment at 6 months (33% compared with 19% of those in the transseptal arm), but substantial loss to follow-up was present.CONCLUSIONS:Among patients undergoing left ventricular catheter ablation procedures, a transseptal approach reduced the risk of acute brain lesions by nearly half compared with a retrograde aortic approach without sacrificing safety or efficacy. Given a likely embolic pathogenesis, the brain magnetic resonance imaging findings may reflect a propensity to other organ damage; these findings may extend to other procedures requiring left ventricular entry.REGISTRATION:URL: https://www.clinicaltrials.gov; Unique identifier: NCT03946072.

Background Cardioneural ablation (CNA) shows promise as a viable alternative to permanent cardiac pacing and pharmacotherapy for patients with symptomatic functional bradycardia and debilitating vasovagal syncope (VVS). The evidence supporting a potential therapeutic role for CNA is limited by relatively small sample sizes from predominantly single-center reports. Objectives This study sought to report the feasibility, safety, and clinical efficacy of CNA from a large, first-ever multicenter US registry. Methods A multicenter registry from 15 US sites was established by collecting data from consecutive patients undergoing CNA for recurrent VVS or symptomatic functional bradycardia (sinus bradycardia [SB] or atrioventricular block [AVB]) refractory to medical therapy and behavioral modification (2018-2024). Results A total of 205 patients who underwent 210 CNA procedures were included. The mean age was 47 ± 17 years, 49% were female, and baseline left ventricular ejection fraction was 60% ± 5%. The most common indication for CNA was syncope in 66.3% (VVS 61.5%, syncope related to AVB 4.9%), followed by SB in 31.2%, AVB in 1.5%, or both SB and AVB in 0.9%. An anatomical approach to target typical ganglionated plexus locations was implemented in all cases, with high-frequency stimulation in 47% of procedures. Endocardial ablation targeting ganglionated plexuses was performed in both atria in 77%, with 697 ± 515 seconds of radiofrequency application. Vagal and sympathetic responses during ablation were observed in 52% and 73% of cases, respectively. The mean increase in heart rate immediately after ablation was 20 ± 15 beats/min. Complications were observed in 4.7% of procedures: 2 respiratory failures requiring bilevel positive airway pressure, 1 right diaphragmatic paralysis, and 4 sinus node dysfunction, with a major adverse event rate of 1.4% (2 hemopericardium, 1 death). At a mean follow-up of 14 ± 11 months, 78% of patients with syncope remained free from recurrence, with a reduction in episodes from a median of 7 (4-15) episodes to a median of 0 (0-0) episodes. Overall, 97% of the cohort remained free from pacemaker implantation. Conclusions In the largest multicenter CNA experience to date, acceleration of baseline heart rate and a significant reduction in syncope burden were achieved with an acceptable rate of major procedural complications. These observational data pave the way for future randomized trials to evolve CNA indications beyond compassionate usage for managing functional bradycardia and reflex syncope.

BACKGROUND:Pulsed field ablation (PFA) may lead to acute kidney injury (AKI), which is believed to be mediated by hemolysis. Although a dose-dependent response has been suspected, only a few small studies have examined the dose-range effect relationship between the number of PFA applications and renal injury. OBJECTIVE:This study aimed to assess the incidence of PFA-induced AKI in real-world practice and identify risk factors for AKI after PFA for atrial fibrillation (AF) with a high number of applications. METHODS:Data of 115 consecutive patients treated with PFA for AF were prospectively collected. Pre- and 24-hour postprocedural laboratory parameters were used to determine the development of hemolysis and AKI and were analyzed for correlation with number of PFA applications. RESULTS:Although biochemical hemolysis was ubiquitously observed after the PFA procedure, 8 patients (7%) developed AKI with only 1 case of clinically significant renal dysfunction. There was no statistical difference in PFA applications between the AKI (88.25 ± 35.37) and non-AKI groups (70.12 ± 16.94, P = .5). The change in serum creatinine (SCr) 24 hours after the procedure was comparable across 4 subgroups based on PFA applications in quartiles (P = .1). A clinically relevant increase in SCr of 0.004 mg/dL per pulse was observed only when patients received more than 38 PFA applications, leading to approximately 140 pulses being required to produce 0.3 mg/dL increase in SCr to meet the criteria of AKI. CONCLUSION:The safety margin for the number of PFA applications seems to be higher in real-world practice; delivering 70-100 PFA applications via a pentaspline catheter during AF ablation remains a relatively low risk of AKI.

BACKGROUND:There is no established imaging technique to detect and diagnose periaortic scar, an increasingly prevalent and challenging substrate referred for ventricular tachycardia (VT) ablation. We hypothesized that wall thinning detected with intracardiac echocardiography (ICE) can identify periaortic arrhythmogenic substrate (PAS) in patients with structural heart disease. OBJECTIVES:This study sought to validate a new method of identifying PAS using ICE in comparison with electro-anatomic mapping and cardiac magnetic resonance (CMR). METHODS:A total of 84 VT ablation patients were analyzed (87% male, median age 72 years [Q1-Q3: 63-75 years], 61% with nonischemic cardiomyopathy) and categorized into 2 groups: PAS+ (n = 29) and PAS- (n = 55) based on voltage-defined scar and deceleration zones. Wall thickness of the basal anterior septum was measured by ICE and CMR at a standardized distance from the left ventricular ostium in diastole by an independent core lab. In 43 patients with CMR, correlation with late gadolinium enhancement (LGE) in the basal anterior septum was also assessed. RESULTS:A significant difference in wall thickness measured at 1 cm from the left ventricular ostium with ICE was observed between PAS+ and PAS- patients (0.57 cm [Q1-Q3: 0.51-0.65 cm] vs 0.72 cm [Q1-Q3: 0.65-0.79 cm]; P < 0.001). Wall thickness by ICE had higher diagnostic performance than CMR, with only 50% of PAS+ patients exhibiting LGE. At a cutoff of <0.60 cm, the sensitivity and specificity of ICE predicting PAS+ were 58% and 87% (positive predictive value 71%, negative predictive value 80%) in comparison with 50% and 84% (positive predictive value 69%, negative predictive value 70%) with CMR-LGE, respectively. CONCLUSIONS:ICE-detected wall thinning may be a novel imaging technique to identify arrhythmogenic periaortic VT substrate in this challenging anatomic region, which often eludes diagnosis with CMR. The absence of LGE on CMR does not rule out the presence of periaortic substrate in patients presenting with outflow tract VT.

BACKGROUND:Being overweight has been associated with arrhythmia recurrence after atrial fibrillation (AF) ablation, but the optimal threshold to identify high risk patients has not been well established. Studies investigating the relationship between underweight and ablation outcome are also limited. This study aimed to investigate the impact of body mass index (BMI) on the recurrence after AF ablation and to determine the optimal cut-off of BMI to identify patients at risk of recurrence. METHODS:Paroxysmal AF (PAF) patients undergoing primary ablation with pulmonary vein isolation were enrolled. Patients were grouped based on 3 BMI discretization methods: pre-defined BMI category, BMI quartile and optimal equal hazard cut-off. Atrial tachyarrhythmia recurrence at 12-month after ablation was the study endpoint which was compared between groups by using the Kaplan-Meier method. RESULTS:Out of 561 patients (mean BMI 25.5 ± 5.1 kg/m2) enrolled, arrhythmia recurrence at 12-month after ablation was found in 29 (43.9 %) of 66 underweight, 39 (21.7 %) of 180 normal weight, 30 (17.4 %) of 172 overweight, and 50 (35.0 %) of 143 obese patients (Log Rank P < 0.001). BMI presented a "U" shape relationship with arrhythmia-free survival. Hazard-based optimal BMI was 20.00 kg/m2 for left cutoff and 29.14 kg/m2 for right cutoff. In multivariable analysis, BMI ≤ 20.00 kg/m2 (HR=2.258, P < 0.001) or > 29.14 kg/m2 (HR=1.702, P = 0.006) was independently associated with arrhythmia recurrence after adjustment of other confounders. CONCLUSIONS:The relationship between atrial tachyarrhythmia recurrence after PAF ablation and pre-ablation BMI appeared to be U-shaped. Individuals whose BMI was ≤20.00 kg/m2 or >29.14 kg/m2 were at high risk of arrhythmia recurrence.