A prolonged PR interval is a sign of increased risk of cardiac arrhythmia. Recent genome-wide association studies found that the single-nucleotide polymorphism (SNP) rs3825214 in T-box 5 (TBX5) was positively associated with PR interval, QRS duration, QT interval, and common arrhythmia disorders such as atrial fibrillation (AF) and advanced atrioventricular block. However, other independent replication studies are required to validate the result. This study assessed associations between rs3825214 and ECG parameters, AF, and ventricular tachycardia (VT) in a Chinese Han population.

To assess the association between rs3825214 and AF and VT, we carried out case-control association studies with 692 AF patients (including 275 lone AF patients), 235 VT patients, and 856 controls. Genotyping was performed using a Rotor-Gene TM 6000 High Resolution Melt system. Statistical analyses of associations were adjusted for potential confounding factors. A moderate association was detected between rs3825214 and AF (P_adj = 0.036, OR = 0.79) and a highly significant association was detected between the G allele of rs3825214 and lone AF (P_adj = 0.001, OR = 0.65; genotypic P = 3.75×10⁻⁴ with a dominant model). We also found that rs3825214 showed a significant association with atrial-ventricular block (AVB; P = 0.028; P_adj = 0.035, OR = 0.494).

Our results indicate that rs3825214 conferred a significant risk of lone AF in this Chinese Han population.