Bakhtawar Khan Mahmoodi

Pulsed field ablation (PFA) has rapidly emerged as a promising ablation modality for the treatment of cardiac arrhythmias because of its myocardial tissue preferential ablation and favourable safety profile. However, procedural control of lesion formation and reliable assessment of lesion durability remain important challenges. This review summarizes the main determinants of PFA efficacy and current approaches for intraprocedural lesion assessment. Experimental and clinical studies indicate that PFA lesion formation results from the interaction between delivered electrical energy, catheter design, tissue coupling, and application strategy. Lesion size and geometry are primarily determined by electric field distribution and cumulative electroporation exposure, while excessive energy delivery may induce unwanted thermal or electrochemical effects. Procedural efficacy also depends on stable catheter positioning, adequate tissue proximity, and sufficient lesion overlap. Unlike thermal ablation technologies, conventional procedural markers such as electrogram attenuation, impedance changes, and pacing threshold variation correlate poorly with durable irreversible electroporation. Multiparametric lesion estimation models integrating electrical, mechanical, and positional data have shown encouraging preclinical results, although clinical validation remains limited. Emerging strategies combining electroanatomical mapping, imaging, and automated electrogram analysis may improve real-time evaluation of lesion continuity and durability. Current PFA workflows rely mainly on standardized energy delivery protocols, optimized catheter positioning, and lesion overlap rather than real-time titration of energy. Although robust intraprocedural markers of irreversible electroporation are still lacking, ongoing advances in catheter technology, imaging, and lesion assessment tools are expected to improve procedural reproducibility and long-term lesion durability. Further studies are needed to establish validated endpoints for durable PFA lesion formation.

ClinicalTrials.gov registration: NCT07014423.

Background: Catheter ablation of regular atrial tachyarrhythmias (ATs) relies on high-density electroanatomical mapping and can be technically challenging. We compared the mapping efficiency of the Octaray and Pentaray catheters in patients undergoing AT mapping. Methods: Patients with either left or right AT underwent three-dimensional Coherent mapping using both the Octaray and Pentaray catheters in a randomized cross-over design. The primary endpoint was the total number of electrograms acquired per map at a predefined filling threshold of 5 mm. Results: A total of 46 patients with left or right AT were enrolled across three ablation centers. Successful mapping with both catheters was achieved in 39 patients (20 left ATs and 19 right ATs). The median number of electrograms acquired per map (7437 vs. 4679; p < 0.001) and median electrogram density (50.2 vs. 29.8 electrograms/cm²; p < 0.001) was significantly higher with Octaray than with Pentaray. Furthermore, median mapping times were significantly shorter with Octaray (5.4 vs. 8.1 min; p < 0.001), resulting in an approximately 2.5-fold higher acquisition rate (1489 vs. 602 electrograms/minute; p < 0.001). In addition, Octaray demonstrated a significantly lower proportion of internal points compared with Pentaray, particularly in low-voltage regions (bipolar voltage < 0.5 mV; 22% vs. 44%; p = 0.01). Conclusions: Compared with Pentaray, use of the Octaray catheter facilitated faster high-density electroanatomical mapping of complex ATs, thereby improving mapping efficiency.

Background: Whether factor V Leiden is associated with lower bleeding risk in patients with acute coronary syndromes using (dual) antiplatelet therapy has yet to be investigated. Methods and Results: We pooled data from 3 randomized clinical trials, conducted in patients with acute coronary syndromes, with adjudicated bleeding outcomes. Cox regression models were used to obtain overall and cause‐specific hazard ratios (HRs) to account for competing risk of atherothrombotic outcomes (ie, composite of ischemic stroke, myocardial infarction, and cardiovascular death) in each study. Estimates from the individual studies were pooled using fixed effect meta‐analysis. The 3 studies combined included 17 623 patients of whom 969 (5.5%) were either heterozygous or homozygous (n=23) carriers of factor V Leiden. During 1 year of follow‐up, a total of 1289 (7.3%) patients developed major (n=559) or minor bleeding. Factor V Leiden was associated with a lower risk of combined major and minor bleeding (adjusted cause‐specific HR, 0.75; 95% CI, 0.56–1.00; P =0.046; I ² =0%) but a comparable risk of major bleeding (adjusted cause‐specific HR, 0.93; 95% CI, 0.62–1.39; P =0.73; I ² =0%). Adjusted pooled cause‐specific HRs for the association of factor V Leiden with atherothrombotic events alone and in combination with bleeding events were 0.75 (95% CI, 0.55–1.02; P =0.06; I ² =0%) and 0.75 (95% CI, 0.61–0.92; P =0.007; I ² =0%), respectively. Conclusions: Given that the lower risk of bleeding conferred by factor V Leiden was not counterbalanced by a higher risk of atherothrombotic events, these findings warrant future assessment for personalized medicine such as selecting patients for extended or intensive antiplatelet therapy.

Background: The prothrombotic defect factor V Leiden (FVL) may confer higher risk of ST‐segment–elevation myocardial infarction (STEMI), compared with non–ST‐segment–elevation acute coronary syndrome, and may be associated with more myocardial necrosis caused by higher thrombotic burden. Methods and Results: Patients without history of cardiovascular disease were selected from 2 clinical trials conducted in patients with acute coronary syndrome. FVL was defined as G‐to‐A substitution at nucleotide 1691 in the factor V (factor V R506Q) gene. Odds ratios were calculated for the association of FVL with STEMI adjusted for age and sex in the overall population and in the subgroups including sex, age (≥70 versus P =0.59) for the association of FVL with STEMI. Subgroup analysis did not show any differences. In patients with STEMI, neither the median peak creatine kinase‐myocardial band nor the peak high‐sensitivity troponin ratio showed any differences between wild‐type and FVL carriers ( P for difference: creatine kinase‐myocardial band=0.33; high sensitivity troponin ratio=0.54). Conclusions: In a general population with acute coronary syndrome, FVL did not discriminate between a STEMI or non–ST‐segment–elevation acute coronary syndrome presentation and was unrelated to peak cardiac necrosis markers in patients with STEMI. Registration: URL: https://www.clinicaltrials.gov ; Unique identifiers: NCT00391872 and NCT01761786.

Background: In patients undergoing transcatheter aortic valve implantation without an indication for oral anticoagulation, it is unclear whether single or dual antiplatelet therapy (DAPT) is necessary to minimize both the bleeding and thromboembolic risk. In this patient‐level meta‐analysis, we further investigate the effect of aspirin alone compared with DAPT for preventing both thromboembolic and bleeding events after transcatheter aortic valve implantation. Methods and Results: We conducted a systematic review of all available randomized controlled trials comparing aspirin with DAPT. In total, 1086 patients were included across 4 eligible trials. The primary outcomes were the composite of all‐cause mortality, major or life‐threatening bleeding, stroke or myocardial infarction (first composite outcome), and the same composite excluding bleeding (second composite outcome), both tested at 30 days and 3 months. The first composite outcome occurred significantly less in the aspirin‐alone group at 30 days (10.3% versus 14.7%, odds ratio [OR], 0.67; 95% CI, 0.46–0.97, P =0.034) and 3 months (11.0% versus 16.5%, hazard ratio [HR], 0.66; 95% CI, 0.47–0.94, P =0.02), compared with the DAPT group. The second composite outcome occurred in 5.5% and 6.6% at 30 days (OR, 0.83; 95% CI, 0.50–1.38, P =0.47) and in 6.9% and 8.5% at 3 months in the aspirin‐alone group compared with the DAPT group (HR, 0.82; 95% CI, 0.52–1.29, P =0.39), respectively. Conclusions: In patients without an indication for oral anticoagulation undergoing transcatheter aortic valve implantation, aspirin alone significantly reduced the composite of thromboembolic and bleeding events, and does not increase the composite of thromboembolic events after transcatheter aortic valve implantation, compared with DAPT.