Material and methods:
The study group consisted of 119 patients diagnosed with atrial fibrillation. There were 57 women and 62 men, aged 65.3+/-9.4 years. The essential co-morbidities were reported. There were 65 patients with paroxysmal AF (AF group), in sinus rhythm during examination and 54 patients with persistent AF. In this group the electrical cardioversion was performed to restore the sinus rhythm (CV group). An antiarrhythmic medication, including beta-blockers, propafenone and amiodarone, also in combinations, was also recorded. As the exact duration of the arrhythmia episodes was not possible to recollect, we only included the patients with persistent AF lasting from 2 to 24 weeks.
The P wave duration, was measured using LabSystemTMPro EP Recording System, Boston Scientific, where the ECG tracings allowed assessing the sinus P waves. The P wave duration was measured precisely in all leads at paper speed of 200 mm/s and enhancement 64-128. To avoid any influence of accidental measurement inaccuracies all the measurements were repeated 5 times and the mean value was presented as a result.
In patients with persistent form of atrial fibrillation the direct current cardioversion was performed as standard clinical procedure under general anesthesia using propofol 1 mg/kg and fentanyl 50 µg, administered intravenously. Single shock of 300 J was successful in all patients.
The study protocol was approved by the local Bioethical Committee at Wroclaw Medical University.