Does Maturity Affect Cephalic Perfusion and T/QRS Ratio during Prolonged Umbilical Cord Occlusion in Fetal Sheep?
Figure 1
Examples of the ECG complex taken from a 0.7 gestation fetus. (a) A representative fetal ECG complex with identification of the ST segment, T wave amplitude, and QRS amplitude. The T/QRS ratio is calculated for each complex by division of the T wave amplitude by the QRS amplitude, thus correcting for changes in signal gain from electrode placement and fetal movement. (b) The ECG complex during the baseline period. (c) Characteristic ST segment elevation early during the occlusion when the fetus is compensating well. (d) Gradual reduction in ST segment elevation concordant with a fall in T/QRS ratio as the fetus starts to compromise from prolonged asphyxia. (e) Progressive T wave inversion immediately after prolonged severe asphyxia.
