P wave dispersion on 12-lead electrocardiography in patients with paroxysmal atrial fibrillation

The prolongation of intraatrial and interatrial conduction time and the inh omogeneous propagation of sinus impulses have been shown in patients with a trial fibrillation. Recently P wave dispersion (PWD), which is believed to reflect inhomogeneous atrial conduction, has been proposed as being useful for the prediction of paroxysmal atrial fibrillation (PAF). Ninety consecut ive patients (46 men, 44 women; aged 55 +/- 13 years) with a history of idi opathic PAF and 70 healthy subjects (42 men, 28 women; mean age 53 +/- 14 y ears) were studied. The P wave duration was calculated in all 12 leads of t he surface EGG. The difference between the maximum and minimum P wave durat ion was calculated and this difference nias defined as P wave dispersion (P WD = Pmax - Pmin). All patients and controls were also evaluated by echocar diography to measure the left atrial diameter and left ventricular ejection fraction (LVEF). There was no difference between patients and controls in gender (P = 0.26), age (P = 0.12), LVEF (66 +/- 4% vs 67 +/- 5%, P = 0.8) a nd left atrial diameter (36 +/- 4 mm vs 34 +/- 6 mm, P = 0.13). P maximum d uration was found to be significantly higher in patients with a history of PAF (116 +/- 17 ms) than controls (101 +/- 11 ms, P < 0.001). P wave disper sion was also significantly higher in patients than in controls (44 +/- 25 ms vs 27 +/- 10 ms, P < 0.001). There was a weak correlation between age an d P wave dispersion (r = 0.27, P < 0.001). A P maximum value of 106 ms sepa rated patients with PAF from control subjects r with a sensitivity of 83%, a specificity of 72%, and a positive predictive accuracy of 79%. A P wave d ispersion value of 36 ms separated patients from control subjects with a se nsitivity of 77%, a specificity of 82%, and a positive predictive accuracy of 85%. In conclusion, P maxim um duration and P wave dispersion calculated on a standard surface ECG are simple ECG markers that could be used to ide ntify the patients with idiopathic paroxysmal atrial fibrillation.