Background Pulsed field ablation (PFA) has gained prominence for pulmonary vein isolation (PVI) to treat atrial fibrillation, but there are limited outcome data on PFA to treat persistent atrial fibrillation (PerAF). Objectives This study sought to determine the safety and efficacy of PVI + posterior wall ablation (PWA) with PFA in PerAF. Methods ADVANTAGE AF (A Prospective Single Arm Open Label Study of the FARAPULSE Pulsed Field Ablation System in Subjects with Persistent Atrial Fibrillation) is a prospective, single-arm, multicenter pivotal investigational device exemption study of PerAF patients undergoing PVI+PWA with the pentaspline PFA catheter. One-year follow-up included 24-hour Holter monitoring at 6 and 12 months and twice monthly and symptomatic transtelephonic monitoring. The primary safety endpoint was incidence of predefined adverse events. The primary effectiveness endpoint included acute success and postblanking 1-year freedom from atrial tachyarrhythmia recurrence (>30 seconds), redo ablation, cardioversion, or antiarrhythmic drug escalation. Endpoint analysis used Kaplan-Meier methodology with 97.5% 1-sided confidence limits compared with a 12% safety and 40% effectiveness goals, with 85% power. Results PFA in 339 patients (260 treatment and 79 roll-in) resulted in 99.7% success for both PVI and PWA. The primary safety endpoint was 2.3% (5.1% upper confidence limit), including 1 with pericarditis, 1 with myocardial infarction, and 4 with pulmonary edema; no tamponade, stroke, pulmonary vein stenosis, or esophageal fistula occurred. Primary effectiveness was 63.5% (57.3% lower confidence limit) at 1 year, with 8.5% patients having a single, isolated atrial fibrillation recurrence. Freedom from symptomatic atrial fibrillation was 85.3%; efficacy varied by operator experience. Conclusions ADVANTAGE AF, the first large prospective study of PFA to treat PerAF using a strategy of PVI and posterior wall isolation, revealed favorable safety and effectiveness outcomes. (A Prospective Single Arm Open Label Study of the FARAPULSE Pulsed Field Ablation System in Subjects with Persistent Atrial Fibrillation [ADVANTAGE AF]; NCT05443594).

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 This paper aims to review and compare the mechanical and technical similarities and differences between the Arctic Front series cryoballoons from Medtronic and the next-generation cryoballoons, including POLARx and POLARx FIT from Boston Scientific and Nordica from Synaptic. As cryoballoon technology continues to evolve, the introduction of lower-pressure and selectable-size balloons presents new considerations for both safety and efficacy of cryoablation of atrial fibrillation.

Cavotricuspid isthmus ablation (CTI) is a first-line therapy in patients with typical atrial flutter. With the advent of pulsed field (PF) as a new energy source, we sought to evaluate the use of PF for CTI ablation. A systematic literature search was conducted on the use of PF for CTI-flutter up to December 2024. A meta-analysis was performed for studies reporting pooled data, while individual case reports were reviewed and summarized. The mean number of PF applications, acute success rate, and prevalence of coronary vasospasm were evaluated. Eleven studies with pooled data from 155 patients were included. All patients had an acute block of the CTI. The mean number of PFA applications was 7.78 (95% CI 6.53-9.48). The incidence of ST-elevation was 0.04% (95% CI 0-2.23%). Subclinical vasospasm was documented in 45% (95% CI 32%-59%) of patients who underwent periprocedural coronary angiography. Prophylactic use of nitrates showed a trend toward reducing the incidence of subclinical vasospasm (RR 0.24, 95% CI 0.06-1.06, p = 0.059). Twelve cases with patient-level data were included; six reported complications, including ST elevation and conduction disturbances. PFA for CTI flutter demonstrates high acute success; however, evidence regarding the durability of the block is limited. Clinical vasospasm with ST segment elevation is uncommon but can lead to life-threatening complications. The incidence of subclinical vasospasm is high, and nitrates tend toward reducing this phenomenon. To date, the role of PFA for this condition appears to be limited.

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.

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant inherited cardiomyopathy characterized by left ventricular hypertrophy. It is one of the chief causes of sudden cardiac death in younger people and athletes. Molecular-genetic studies have confirmed that the vast majority of HCM is caused by mutations in genes encoding sarcomere proteins. HCM has a relatively wide phenotypic heterogeneity, varying from asymptomatic to sudden cardiac death, because of the many different mutations and pathogenic genes underlying it. Many studies have explored the clinical symptoms and prognosis of HCM, emphasizing the importance of genotype in evaluating patient prognosis and guiding the clinical management of HCM. To elaborate the main pathogenic genes and phenotypic prognosis in HCM to promote a better understanding of this genetic disease. Retrospective analysis of literature to evaluate the association between underlying gene mutations and clinical phenotypes in HCM patients. As sequencing technology advances, the pathogenic gene mutation spectrum and phenotypic characteristics of HCM are gradually becoming clearer. HCM is a widespread inherited disease with a highly variable clinical phenotype. The precise mechanisms linking known pathogenic gene mutations and the clinical course of this heterogeneous condition remain elusive.

Pulsed field ablation (PFA) is a cutting-edge treatment for arrhythmias that targets cardiac tissue with rapid, high-voltage electric current pulses, resulting in irreversible electroporation. Freed from the constraints of traditional radiofrequency (RF) ablation, the non-thermal mechanism and myocardial selectivity of PFA has improved procedural safety aspects and efficiency over RF ablation. However, catheter development thus far has focused on waveforms and voltage, such that critical aspects related to the physics of energy delivery at the tissue-blood interface were often overlooked. When delivering high-voltage pulsed electric fields, differences in electrical impedance, catheter geometry, and field strength impact the resulting precision and durability of lesions; principles that warrant a deeper understanding to inform and optimize future catheter designs. This article examines the engineering considerations behind the success of the first industrial iterations of PFA, with a comparison of catheter form factors for current systems that impact energy delivery, workflow, safety, and performance. We also address the initial assumptions and misconceptions related to PFA design and the development of current generation catheters as considerations for the future of ablation and mapping.