Abnormal atrial activation in young patients with lone atrial fibrillation

AIMS: Patients with a history of atrial fibrillation (AF) have previously been shown to have altered atrial conduction, as seen non-invasively using signal-averaged P-wave analysis. However, little is known about the P-wave morphology in patients in the early phases of AF with structurally normal hearts. METHODS AND RESULTS: Thirty-six patients with lone AF were included before the age of 40 years (34±4 years, 34 men) and compared with age- and gender-matched control subjects. Standard 12-lead electrocardiogram (ECG) was recorded for at least 10 s. P-wave morphology and duration were estimated using signal-averaged P-wave analysis. Echocardiography was performed in association with the ECG recording. Heart rate (67±13 vs. 65±7 b.p.m., P=0.800) and PQ-interval (163±16 vs. 164±23 ms, P=0.629) were similar in AF cases and controls, as was P-wave duration (136±13 vs. 129±13 ms, P=0.107). The distribution of P-wave morphology differed between the AF cases and controls 33/58/0/8 vs. 75/25/0/0% (Type 1/Type 2/Type 3/atypical), P=0.001, with a larger proportion of patients with AF exhibiting signs of impaired interatrial conduction. CONCLUSION: A significant difference in P-wave morphology distribution was seen between patients with early-onset, lone paroxysmal AF and age- and gender-matched healthy control subjects. This finding indicates that alterations in atrial electrophysiology are common in the early stage of the arrhythmia, and since it occurs in young patients without co-morbidity may well be the cause rather than the consequence of AF.