P Wave Dispersion in Patients with Mitral Stenosis and Effects of Percutaneous Mitral Balloon Valvuloplasty on P Wave Dispersion

P wave dispersion (PWD) is a new electrocardiographic marker that has been associated with inhomogeneous and discontinuous propagation of sinus impulses. It can be defined as the difference between maximum and minimum P wave duration. Recent studies have been reported that prolonged P wave duration and increased P wave dispersion carry an increased risk for atrial fibrillation. The objectives of this study were to determine PWD in patients with mitral stenosis (MS), and to evaluate the effects of percutaneous mitral balloon valvuloplasty (PMBV) on PWD. The study population consisted of two groups: Group I consisted of 29 patients with MS (26 women, 3 men; aged 33±6 years) who were candidate for PMBV and Group II consisted of 27 healthy volunteers (24 women, 3 men; aged 32±7 years). Twelve-lead electrocardiogram (ECG) was recorded and echocardiographic evaluation was performed for each patient one day before PMBV and repeated at first day, at the end of the first month and at sixth month after successful PMBV. Baseline maximum P wave duration and PWD of group I were significantly higher than those of group II (p<0.001). However there was no statistically significant difference between group I and group II regarding minimum P wave duration (p>0.05). Maximum P wave duration and PWD decreased progressively on measurements at first day, at the end of the first month and at sixth month after PMBV (p<0.001, table-II). When the maximum P wave duration and PWD measused on first day, at the end of the first month and at sixth month were compared with each other, a significant decrease was also detected (p<0.01, table-II). There was no statistically significant difference between the values of minimum P wave duration measured before PMBV, at first day, at the end of the first month and at sixth month after PMBV. There was no statistically significant correlation between the decrease in PWD and the improvement in echocardiographic parameters. In conclusion, PWD is significantly higher in patients with mitral stenosis indicating high risk for atrial fibrillation, than in healthy control subjects and it decreases significantly after PMBV both in short and long term.