P-wave dispersion is increased in pregnancy due to shortening of minimum duration of P: does this have clinical significance?

Most pregnant women complain of palpitation, and various kinds of arrhythmias can be observed during pregnancy. We investigated P-wave and QT dispersion during pregnancy. Healthy pregnant women (n=162) and healthy age-matched, non-pregnant women (n=150) were included. We performed electrocardiography and transthoracic echocardiography and determined serum oestradiol levels in both groups, and performed Holter monitoring in the pregnant group only. Resting heart rate, P-wave dispersion, left ventricular diastolic diameter, left atrial diameter and serum oestradiol levels in the pregnant group were significantly higher than in the control group. Minimum P-wave duration was shorter in the control group than in the pregnant group; however, there was no statistically significant difference in maximum P wavelength and corrected QT dispersion between the groups. No atrial fibrillation was detected in the pregnant group during Holter monitoring. Shortening of the minimum P-wave duration leads to increased P-wave dispersion during pregnancy. In contrast to other pathologies with increased P-wave dispersion, paroxysmal atrial fibrillation is absent in pregnant women; this may be a result of the stable maximum P wavelength that is present during pregnancy.