Some genetic susceptibility loci for atrial fibrillation (AF) identified by genome-wide association studies (GWAS) in a European database showed ethnic differences in the Asian population. We explored novel AF susceptibility variants for patients with early-onset AF (≤60 years old) among Korean patients who underwent AF catheter ablation. A genome-wide association study (GWAS) was conducted with 672 cases (≤60 years old, Yonsei AF Ablation cohort) and 3700 controls (Korea Genome Epidemiology Study). Association analysis was performed under an additive model of logistic regression, and replication study was conducted with 200 independent cases of Korean AF Network and 1812 controls. Five previously proven genetic loci (1q24/PRRX1, 4q25/PITX2, 10q24/NEURL, 12q24/TBX5, and 16q22/ZFHX3) were validated. Two novel genetic loci associated with early-onset AF were found on chromosomes 1q32.1/PPFIA4 (rs11579055, P = 6.84 × 10⁻¹⁰) and 4q34.1/HAND2 (rs8180252, P = 1.49 × 10⁻¹¹) and replicated in an additional independent sample of the Korean AF Network. The identified loci implicate candidate genes that encode proteins related to cell-to-cell connection, hypoxic status, or long non-coding RNA. Two novel genetic loci for early-onset AF were identified in Korean patients who underwent catheter ablation. One of the novel susceptibility loci on chromosome 4 has strong associations with previously proven gene in a European ancestry database.

Radiofrequency catheter ablation (RFCA) targeting the left ventricular posteroseptum (LVPS) and posterior papillary muscle (PPM) terminates or prevents ventricular fibrillation (VF) in rabbit and dog hearts. However, whether the mechanism of VF maintenance is reentry or focal Purkinje firing is unclear. In the present study the effects of RFCA (endocardial ablation of PPM+LVPS in 7 dogs and 7 swine), left ventricular anterolateral wall ablation (LVAL in 7 dogs), and the cut-and-sew operation (CSO: along the left ventricular posterior wall (LVPW) beside PPM in 7 swine) on VF inducibility were compared. (1) VF inducibility was decreased from 100+/-0% to 21.9+/-31.2% (p<0.0001) by PPM+LVPS endocardial ablation, but not by LVAL ablation in dogs. (2) LVPW CSO reduced VF inducibility (100+/-0% to 43.6+/-9.5%, p<0.0001) in swine. (3) In contrast to the canine Purkinje network, which is mostly localized to the subendocardium, the swine Purkinje network extends to the subepicardial layer with a higher density (p<0.001). Both PPM+LVPS ablation (Purkinje destruction) in dogs and LVPW CSO (blocking reentry) in swine reduce VF inducibility, suggesting that in both species focal firing from the Purkinje network and reentry around the PPM contributes to the maintenance of VF.

Korean Circulation Journal 대한심장학회지 순환기 Roh SY, et al. Korean Circ J. 2021 Oct;51(10):866-874. https://doi.org/10.4070/kcj.2021.0127