Saagar Mahida

The optimal strategy for ablation of persistent atrial fibrillation (PsAF) remains to be defined. Established substrate‐based ablation techniques, particularly techniques targeting complex electrograms, with complementary linear ablation for organized atrial tachycardias, have been associated with modest success rates. Recently, the development of VoM ethanol ablation (Et‐VoM) has facilitated ablation of previously inaccessible arrhythmogenic substrate. This has allowed comparison of a standardized anatomically‐guided protocol with Et‐VOM to a traditional electrophysiology‐guided approach for PsAF ablation.

Funding Acknowledgements: Type of funding sources: None. Introduction: Catheter ablation for atrial fibrillation (AF) is largely offered for symptomatic relief. The ORBIT registry has shown that patients with a higher EHRA class and lower quality of life (QoL) scores (AFEQT score <65.7) are more likely to suffer emergency hospital admissions. To help prevent unplanned AF admissions and to best utilise the reduced capacity for elective work during the COVID-19 pandemic, it has become even more important to prioritise the most symptomatic AF patients for ablation. Purpose: To evaluate the accuracy of a subjective symptom-based clinician prioritisation schema compared to objective patient-completed quality of life (QoL) scores. Methods: In July 2020, all elective cases awaiting AF ablation at our institution were categorised by their cardiologist as either category 1 (C1-urgent), category 2 (C2–priority, procedure to be done during the ongoing COVID-19 pandemic) or category 3 (C3–routine, procedure may be delayed until post pandemic). This categorisation was based on review of clinic letters where EHRA AF symptom class or PROMS are not routinely recorded. All patients in C2 and C3 were then posted an AF specific (AFEQT) and a generic (EQ5D) QoL questionnaire to complete. Physicians were blinded to patient responses on the QoL questionnaires. Results: Details of physician prioritisation and completed questionnaires were available for 85 patients (62 ± 10 years, PAF in 61%, males 66%). The 18 patients that had been categorised in C2 (priority) group were found to have a significantly lower AFEQT score (30.4, IQR 17.2-51.9) compared to the 67 patients classed in C3 (routine) group (56.5, IQR 32.1-74.1; p < 0.01)(Figure 1a). EQ5D scores also tended to be lower in the C2 patients (0.7, IQR 0.4-0.8) compared to C3 (0.8, IQR 0.6-0.9; p = 0.056) (Figure 1c). 16 (89%) patients in C2 had significant AF-related impact on QoL (as defined as AFEQT score <65.7) compared to 42 (63%) of patients in C3. However, there was significant overlap between groups (Figure 1b). 4 patients in C3 had unplanned AF related hospital admissions while awaiting ablation, as compared to none in C2. The median AFEQT score of these 4 patients was 23.3, indicating that they were highly symptomatic despite being classified in C3 by their cardiologist. Conclusion : Physician assessments are moderately accurate in prioritising patients awaiting AF ablation. The addition of formal patient-completed QoL assessment such as with AFEQT, helps to identify the most symptomatic patients at risk of emergency hospital admission, and physicians should consider using these as part of routine assessment, especially during the COVID pandemic. Abstract Figure 1

The retrograde aortic (RA) route is a widely used access route for mapping and ablation of ventricular tachycardias (VT) arising from the left ventricular endocardium. With the expanding role of VT ablation in patients with significant comorbidity, the choice between the RA and transseptal access routes is an increasingly important consideration. An individualized decision based on the location of the arrhythmogenic substrate, vascular anatomy, aortic valve morphology, and operator experience is necessary when deciding on the optimal access route. Among patients with challenging vascular anatomy, growing experience from structural interventions such as transcatheter aortic valve replacements and peripheral vascular interventions has provided valuable insights into techniques for safe retrograde access. The present review focuses on patient selection for RA access, potential complications associated with the technique, and optimal approaches for access in patients with challenging vascular or aortic valve anatomy.

Background: A large number of SCN5A variants have been reported to underlie Brugada syndrome (BrS). However, the evidence supporting individual variants is highly heterogeneous.Objective: We systematically re‐evaluated all SCN5A variants reported in BrS using the 2015 American college of medical genetics and genomics and the association for molecular pathology (ACMG‐AMP) guidelines.Methods: A PubMed/Embase search was performed to identify all reported SCN5A variants in BrS. Standardized bioinformatic re‐analysis (SIFT, PolyPhen, Mutation Taster, Mutation assessor, FATHMM, GERP, PhyloP, and SiPhy) and re‐evaluation of frequency in the gnomAD database were performed. Fourteen ACMG‐AMP rules were deemed applicable for SCN5A variant analysis.Results: Four hundred and eighty unique SCN5A variants were identified, the majority of which 425 (88%) were coding variants. One hundred and fifty‐six of 425 (37%) variants were classified as pathogenic/likely pathogenic. Two hundred and fifty‐eight (60%) were classified as variants of uncertain significance, while a further 11 (3%) were classified as benign/likely benign. When considering the subset of variants that were considered “null” variants separately, 95% fulfilled criteria for pathogenicity/likely pathogenicity. In contrast, only 17% of missense variants fulfilled criteria for pathogenicity/likely pathogenicity. Importantly, however, only 25% of missense variants had available functional data, which was a major score driver for pathogenic classification.Conclusion: Based on contemporary ACMG‐AMP guidelines, only a minority of SCN5A variants implicated in BrS fulfill the criteria for pathogenicity or likely pathogenicity.

The early repolarization (ER) pattern on the 12-lead electrocardiogram is characterized by J point elevation in the inferior and/or lateral leads. The ER pattern is associated with an increased risk of ventricular arrhythmias and sudden cardiac death (SCD). Based on studies in animal models and genetic studies, it has been proposed that J point elevation in ER is a manifestation of augmented dispersion of repolarization which creates a substrate for ventricular arrhythmia. A competing theory regarding ERS proposes that the syndrome arises as a consequence of abnormal depolarization. In recent years, multiple clinical studies have described the characteristics of ER patients with VF in more detail. The majority of these studies have provided evidence to support basic science observations. However not all clinical observations correlate with basic science findings. This review will provide an overview of basic science and genetic research in ER and correlate basic science evidence with the clinical phenotype.

NMARQ AF Ablation: Background: nMARQ is a multipolar catheter designed to simultaneously ablate at multiple sites around the pulmonary vein (PV) circumference with a single radiofrequency application. We sought to define the safety and efficacy of atrial fibrillation (AF) ablation with the nMARQ catheter.Methods: In a multicenter study, patients with drug‐refractory AF were included. Procedural outcomes were documented at 1 year.Results: 374 patients underwent PV isolation using nMARQ (age 60 ± 10 years, 264 male), of whom 263 patients had paroxysmal AF (PAF), while 111 patients had persistent AF. A total of 1,468 of 1,474 veins (99.6%) were isolated with the nMARQ catheter alone. Thirty‐five (13%) PAF patients and 30 (27%) persistent AF patients underwent additional ablation at non‐PV sites (2.4 ± 1.4 non‐PV sites). Procedure time for PV isolation only was 1.9 ± 0.7 hours (fluoroscopy 24 ± 14 minutes). Procedure time for PV isolation and non‐PV ablation was 2.4 ± 1.0 hours (fluoroscopy 30 ± 23 minutes). Major adverse events occurred in two patients (0.5%); one esophago‐pericardial fistula and a second, mortality due to sepsis of unknown cause. One‐year follow‐up data were available in 65 (25%) PAF and 20 (18%) persistent AF patients. Forty‐two (65%) PAF and 13 (65%) persistent AF patients were free of arrhythmia at 1 year. In patients undergoing repeat procedures (n = 17) the most frequent points of PV reconnection were: anterior RSPV, inferior RIPV, and superior LSPV.Conclusions: AF ablation with nMARQ is associated with short procedure times and high acute success rates. Further research is necessary to more clearly define long‐term outcome.