The Influence of the Amount of Ultrafiltration in Chronic Hemodialysis on P Wave Dispersion

OBJECTIVE: Paroxysmal atrial fibrillation (AF) observed in patients undergoing chronic hemodialysis program with higher rates is an important morbidity and mortality cause that negatively influences the hemodynamics and leads to thromboembolic complications. It is known that P wave dispersion (PWD) facilitating the development of paroxysmal atrial fibrillation is increasing during intradialytic process. This study researched the influence of various amounts of ultrafiltration that applied in the various hemodialysis sessions in the same patient cohort on PWD. MATERIALS AND METHODS: 25 patients in a chronic hemodialysis program undergoing four hours bicarbonate hemodialysis three times a week were included in the study. The patient cohort was divided into four groups regarding the amount of ultrafiltration (UF) performed during a four-hour standard hemodialysis session as following: UF up to 1 liter, UF of 1-2 liters, UF of 2-3 liters, and UF of 3-4 liters. Notes were kept until each patient had been included once into each group regarding the amount of ultrafiltration performed parallel to intradialytic weight gain in different hemodialysis session. A 12-lead ECG was taken from the patients immediately before the hemodialysis and within 20 minutes after completion of the session, and maximum P wave duration (Pmax), minimum P wave duration (Pmin) and PWD values (i.e., the difference between Pmax and Pmin) were measured. The inter-group data was assessed with a one-way ANOVA, and the within-group assessments were performed with paired samples test. Mann Whitney U test was used for the evaluations performed according to the presence of diabetes. FINDINGS: The mean age of 25 patients (15 male and 10 female) was 62.7 +/- 20.2 (range: 21-89). PWD after UF was decreased significantly in group 1 (56.12 +/- 15.26 vs. 46.60 +/- 18.45 ms, p = 0.018) and were increased in groups with UF more than 1 liter: group 2 (39.68 +/- 21.26 vs. 47.12 +/- 21.20 ms, p = 0.020), group 3 (41.60 +/- 23.99 vs. 65.92 +/- 31.04 ms, p = 0.001), and group 4 (17.52 +/- 14.67 vs. 26.80 +/- 15.52 ms, p = 0.007). Furthermore, while PWD before UF was significantly higher in a diabetic group compared to a nondiabetic group (68.85 +/- 10.44 vs. 51.16 +/- 14.06 ms, p = 0.007), it was seen that PWD difference had disappeared after UF application (57.14 +/- 17.99 vs. 42.50 +/- 17.40 ms, p = 0.065). CONCLUSION: UF application of more than 1 liter during hemodialysis session increases the PWD value significantly. Hypervolemia exceeding 1 liter between two dialysis sessions should be avoided in all patient groups, especially in diabetics, and an effective UF planning should be arranged because of a decrease in PWD values with UF observed in diabetics.