Atrial fibrillation in end stage renal disease patients: influence of hemodialysis on P wave duration and atrial dimension

BACKGROUND: Prevalence and incidence of atrial fibrillation (AF) are high in hemodialysis (HD) patients. Intra-atrial conduction velocity slowing plays an important role in AF onset. The aim of our study was to measure P wave duration (Pwd), expression of intra-atrial conduction velocity, in HD patients with and without a history of AF. METHODS: The study was performed in 47 end stage renal disease (ESRD) patients, subdivided into four groups: 19 patients within the first 6 months from starting HD therapy (HD1); the same patients studied 18 ± 3 months later (HD2); patients with no history of AF and long dialytic age (HD3, n = 13); and patients with sinus rhythm but history of AF (HDAF, n = 15); and 18 healthy controls. In all patients P wave high resolution recording and electrolyte plasma values were obtained before and after a HD session, and atrial diameter was assessed by echocardiography. RESULTS: Patients with the shortest dialysis vintage showed the shortest Pwd [131.2 ± 11.0 (HD1) vs. 139.8 ± 11.7 (HD2), 142.1 ± 7.2 (HD3), 152.3 ± 15.0 (HDAF) ms; p < 0.05], while Pwd was prolonged in patients with AF history when compared to all other groups (p < 0.03). At multivariate analysis atrial dimension was independently related to Pwd (R = 0.40, p < 0.02). HD session induced a significant increase of Pwd (141 ± 14.0-152 ± 17.0 ms, p < 0.001), that was correlated to modifications of K(+) concentration (R = 0.8, p < 0.0001). CONCLUSIONS: HD therapy prolongs Pwd. HD patients with a history of AF have prolonged Pwd compared to patients without, suggesting that increased Pwd is a marker of AF risk in patients with ESRD. HD session acutely increases Pwd, creating conditions favoring AF onset.