One-third of lone atrial fibrillation (AF) presents as familial disorder. Heterogeneity of both genetic background and clinical manifestations remains largely uncharacterized. We aimed to evaluate the clinical characteristics and especially the triggering factors of familial AF.Methods and Results
Probands were screened from 84 consecutive lone AF patients seen in our tertiary hospital arrhythmia clinic. Those confirmed to have at least 1 first-degree relative with lone AF were included. 12-lead ECG, Holter recording, and cardiac ultrasound were performed. Data concerning arrhythmias and other medical history were collected. Altogether 17 kindreds with 59 AF patients, 52 of whom had lone AF, were identified. Initiation of AF was atrial extrasystolia (PACs) related in 35%, and vagal or sympathetic in 30% of cases. Within any given family, the characteristics related to AF initiation were the same in two-thirds of kindreds. AV conduction abnormalities were found in 2 families, sinus node dysfunction in 2 families, and both in 3 families. Frequent premature ventricular complexes (>1,000/24 hours) were observed in 9 families. Additional comorbidities included dilative cardiomyopathy and sudden death in 3 families.Conclusions
In familial AF the proportion of PACs-related AF is lower than expected. The arrhythmia triggers for lone AF in general are heterogeneous but often family specific. Concomitant rhythm disorders, as well as cardiomyopathies, are common in patients with familial AF. A positive family history for AF in an apparently lone AF patient may be a marker for wider spectrum of cardiac pathology.