A first-degree family history in lone atrial fibrillation patients.

Background: Atrial fibrillation (AF) may be due to an inherited trait, particularly in lone AF patients. A family history of AF in lone AF patients has not previously been compared with a family history of patients with AF and established risk factors (non-lone AF).
Objective: The purpose of this study was to compare the frequency of having a first-degree relative with AF in lone and non-lone AF patients.
Methods: We performed a case-control study of consecutive subjects presenting to a single electrophysiology laboratory. A convenience sample of subjects with no known arrhythmias was also enrolled.
Results: Four hundred twenty-nine subjects were enrolled: 136 had AF (54 with lone AF), 84 had atrial flutter, 158 had other supraventricular arrhythmias, and 51 had no known arrhythmias. Significantly more subjects with AF reported a first-degree family history of AF compared with the remainder of the cohort (25% vs. 5%; P <.001). In multivariable analysis adjusting for potential confounders, AF patients had a 6-fold greater odds of having a family member with AF (95% confidence interval [CI] 2.93-12.7; P <.001). Lone AF patients had a first-degree family member with AF substantially more often than those with non-lone AF (41% vs. 14%; P <.001). After adjusting for potential confounders, lone AF patients remained significantly more likely than other AF patients to have a first-degree relative with AF (OR 7.2; 95% CI 2.1-24.7; P = .002).
Conclusion: Lone AF patients have a first-degree family member with AF substantially more often than other AF patients. This suggests that an inherited trait may be particularly important in this subgroup of patients.