QRS axis deviation in Nigerian women during normal pregnancy.

Abstract

The effect of pregnancy on the heart rate, respiratory rate, QRS axis and QRS complex duration of the ECG was investigated in 41 pregnant compared to 39 non pregnant age and height matched Nigerian subjects. Results obtained show that pregnancy had no significant effect (p > 0.05) on heart rate, respiratory rite and QRS complex duration of the ECG. However, the QRS axis showed significant (p < 0.05) left ward deviation in pregnant subjects compared to non-pregnant subjects. The magnitude of the deviation apparently increases as pregnancy progresses. In addition, chi-squared analysis revealed significant association (p < 0.001) between the incidence of left axis deviation in pregnant subjects compared to non-pregnant subjects. Our findings highlight the need for caution in the interpretation of the ECG during the antenatal period.