Noninvasive measurement of isovolumetric contraction time by Doppler cardiography can be substituted for fetal cardiac contractility: evaluation of a fetal lamb study.

OBJECTIVE The objective of this study is to clarify whether the isovolumetric contraction time obtained from Doppler cardiography (Doppler ICT) can be an index substituted for fetal cardiac contractility. MATERIALS AND METHODS In 10 pregnant ewes, fetal hypoxemia was induced by giving a variable mixture of gases. Through experiment, the Doppler ICT, pre-ejection period (PEP), and the maximum first derivative of the left ventricular pressure waveform (Max dp/dt) were simultaneously recorded every 10min. The relationship between both the Doppler ICT and PEP, and the Max dp/dt were analyzed. RESULTS A significant negative linear regression was founded between the Doppler ICT and the Max dp/dt. A significant negative linear regression was also shown between PEP and the Max dp/dt. Moreover, the regression of Max dp/dt on ICT had significantly less residual variance than the regression of Max dp/dt on PEP (p=0.0004). CONCLUSION In contrast to PEP, Doppler ICT is a reliable, and non-invasive index which can be substituted for fetal cardiac contractility.

[1]  P S Reddy,et al.  Direct Correlation of External Systolic Time Intervals with Internal Indices of Left Ventricular Function in Man , 1971, Circulation.

[2]  I. H. Rowe,et al.  The pre-ejection period of the fetal heart: patterns of change during labor. , 1974, American journal of obstetrics and gynecology.

[3]  J. Fleming,et al.  FETAL ELECTROMECHANICAL INTERVALS IN LABOUR , 1978, British journal of obstetrics and gynaecology.

[4]  A. Weissler,et al.  Systolic Time Intervals in Heart Failure in Man , 1968, Circulation.

[5]  L. Organ,et al.  A new computer technique for continuous measurement of the pre-ejection period in the human fetus: physiologic significance of pre-ejection period patterns. , 1980, American journal of obstetrics and gynecology.

[6]  E. Braunwald,et al.  Studies on the first derivative of the ventricular pressure pulse in man. , 1962, The Journal of clinical investigation.

[7]  J. W. Goodwin,et al.  The pre-ejection period of the fetal heart: response to stress in the term fetal lamb. , 1973, American journal of obstetrics and gynecology.

[8]  Prenatal diagnosis of slow‐rate ventricular tachycardia using fetal electrocardiography , 2004, Prenatal diagnosis.

[9]  N Athayde,et al.  The fetal cardiac isovolumetric contraction time in normal pregnancy and in pregnancy with placental vascular disease: the first clinical report using a new ultrasound technique , 2001, BJOG : an international journal of obstetrics and gynaecology.

[10]  Tsuyoshi Koga,et al.  A New Ultrasound Technique to Measure the Isovolumetric Contraction Time as an Index of Cardiac Contractility: Fetal Lamb Validation , 2003, Journal of the Society for Gynecologic Investigation.

[11]  J. Leonard,et al.  True isovolumic contraction time. Its correlation with two external indexes of ventricular performance. , 1970, The American journal of cardiology.

[12]  N Athayde,et al.  A new and simple Doppler method for measurement of fetal cardiac isovolumetric contraction time , 2001, Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology.

[13]  N. Fisk,et al.  Non‐invasive fetal electrocardiography in singleton and multiple pregnancies , 2003, BJOG : an international journal of obstetrics and gynaecology.

[14]  Y Murata,et al.  Systolic Time Intervals of the Fetal Cardiac Cycle , 1974, Postgraduate medicine.

[15]  J. Mitchell,et al.  Hemodynamic determinants of the maximal rate of rise of left ventricular pressure. , 1963, The American journal of physiology.