Subxiphoid left atrial ablation for atrial fibrillation

Atrial fibrillation is becoming a disease that needs to be addressed with definitive long‐term treatment as opposed to medical management options. Ablation or isolation of focal triggers around the pulmonary veins can eliminate arrhythmia substrates for patients with paroxysmal, lone atrial fibrillation. However, limited pulmonary vein isolation strategies do not address reentrant circuits common in persistent and longstanding persistent patients with structural heart disease and enlarged atria. The convergent procedure is a hybrid ablation treatment for atrial fibrillation. It consists of surgical ablation of the posterior left atrium through a minimally invasive closed-chest approach followed by endocardial catheter ablation. The convergent procedure was developed to treat atrial fibrillation by creating a complete and comprehensive pattern of linear lesions on the left atrial backwall under direct endoscopic visualization while avoiding chest incisions and deflation of the lungs. Endocardial ablation follows the epicardial procedure to confirm lesion integrity and supplement the epicardial procedure, which is performed in a staged fashion.

Abstract 16403: Prevalence and Sex Differences in Early-onset Atrial Fibrillation - A Nation-wide Primary Care Study in Norway

Background: Several studies have reported a male:female ratio of 4:1 in lone atrial fibrillation (AF) populations. However, there have been few reports on the young population with AF, and no reports from a primary care setting. Here, we describe prevalence and sex-differences in early-onset AF in a nation-wide register-based study in the primary care sector in Norway. Methods: In Norway, with a population of 5.4 million, healthcare is publicly financed and all general practitioner (GP) claims have been recorded in the Norwegian Control and Payment of Health Reimbursement (KUHR) registry, since 2006. We identified all individuals aged ≥18 and <50 years registered with ≥1 AF diagnosis code (International Classification of Primary Care (ICPC) K78), from 2006-2019 in the KUHR registry. Based on population estimates from Statistics Norway, we calculated the prevalence of early-onset AF in 2019, as a total, by sex, and by age groups: 18-29, 30-39, 40-49. Results: We identified 5563 individuals (28.5% women, age 18-49 years) aged 18-49 in 2019 with AF diagnosed <age 50 years. In 2019, the prevalence of early-onset AF registered in all individuals up to age 50 was 0.24% (women: 0.14% (1585/1114821), men 0.34% (3978/1176555), p=1.4x10 -205 ) with a ratio of 2.5 men:women. In individuals aged 18-29 the prevalence was 0.05% (women 0.04% (164/410367), men 0.07% (292/435001), p=79x10 -8 ). For the age group 30-39 years the prevalence was 0.19% (women 0.12% (408/349639), men 0.27% (985/367730), p=3.9x10 -49 ). For the age group 40-49 years the prevalence was 0.51% (women 0.29% (1013/354815), men 0.72% (2701/373824), p=1.39x10 -155 ). Conclusion: We show that the prevalence of early-onset AF in a nation-wide primary care population is 0.24% and that the sex-difference in prevalence is smaller than previously reported in early-onset and lone AF studies. Our findings underline the need of increased awareness of AF as a disease in the young, and particularly to women in the youngest age-groups.

P1392Next generation sequencing in lone atrial fibrillation patients

Background. Minor part of atrial fibrillation (AF) patients develops the disease without any well-known risk factors, which is a particular form of the disease, known as a lone AF. Rare genetic variants were described as causative for lone AF. The aim of this study was to investigate occurrence of rare genetic variants in lone AF patients. Material and Methods. We performed Mendeliome sequencing for 21 lone AF patients. Lone AF was defined as AF in individuals younger than 65 years in the absence of cardiovascular or structural heart disease, endocrinologic or pulmonary disease, chronic kidney disease, obesity and excessive alcohol consumption. Data analysis was performed by current laboratory pipeline. We analyzed 453 cardiomyopathy, arrhythmias and sudden cardiac death related genes. Results. In eight out of 21 (38%) lone AF patients rare likely pathogenic variants were found (Table 1.). Seven rare truncating TTN variants and one LMNA missense variant were observed. Four unrelated patients were positive for the same TTN variant c.13696 C &gt; T; p.(Gln4566Ter). The same variant was previously found in ARVC patient in our laboratory. Segregation analysis and phenotyping of relatives is ongoing. Conclusions. Rare genetic variants are common causes of the lone atrial fibrillation. TTN gene variant c.13696C &gt; T; p.(Gln4566Ter) is a potential founder variant in the Baltic population. Table 1. Genetic variants in lone AF Gender Age of AF onset Genetic variant Family history Male 53 LMNA: p.(Ser326Thr) AF in mother Male 11 TTN: p.(Trp31854Ter) AF in father Male 30 TTN: p.(GLn4566Ter) AF in uncle Female 45 TTN: p.(GLn4566Ter) Negative Male 37 TTN: p.(GLn4566Ter) AF in father Male 25 TTN: p.(GLn4566Ter) AF in father, maternal and paternal grandmother Female 60 TTN: p.(Arg27414Ter) Sudden cardiac death at the age of 50 in grand father Female 52 TTN: p.(Arg1012Ter) AF in mother