Assessment of fetal left cardiac isovolumic relaxation time in appropriate and small-for-gestational-age fetuses

Цывьян, П. Б.; Malkin, K.; Wladimiroff, J. W.

doi:10.1016/0301-5629(95)00016-k

Cited by 33 publications

(30 citation statements)

References 13 publications

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“…Moreover, a synchronization between the separation of the mitral cuspids and the transmitralic blood flow has been observed in these fetuses. This delay in the left ventricular isovolumetric relaxation time further confirms the presence of an altered diastolic function in fetuses with growth retardation [55]. When the cardiac hemodynamic redistribution, typical of placental insufficiency, leads to heart failure, the venous circulation is also involved.…”

Section: Hemodynamic Cardiac Modifications In Iugr Fetusesmentioning

confidence: 54%

Intrauterine Growth Retardation and Fetal Cardiac Function

Severi¹,

Rizzo

Bocchi³

et al. 2000

Fetal Diagn Ther

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Intrauterine growth retardation is a pathology which is found in 3–10% of all pregnancies and it is associated with around 20–25% of all fetal intrauterine deaths and with long-term neurologic sequelae. It presents an increased risk of distress during labor and delivery and a greater risk of perinatal mortality. The causes of IUGR and the cardiac and venous Doppler in normal fetuses are analyzed, and the hemodynamic cardiac modifications in IUGR fetus are discussed. The fetal cardiac function in intrauterine growth retardation shows a redistribution of the fetal cardiac output, which tends to favor the left ventricle as the mechanism to compensate for the uteroplacental insufficiency. The Doppler velocity indices are modified as the fetal condition progressively deteriorates and they represent an important tool for the management of the complicated pregnancy.

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Section: Hemodynamic Cardiac Modifications In Iugr Fetusesmentioning

confidence: 54%

Intrauterine Growth Retardation and Fetal Cardiac Function

Severi¹,

Rizzo

Bocchi³

et al. 2000

Fetal Diagn Ther

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“…The systolic time intervals of the fetal cardiac cycle have been analyzed by several authors in the past by using pulsed Doppler and M-mode echocardiography [11], digital filtering of DUS [7,8,12,13], frequency spectrogram of DUS by short term fourier transform (STFT) [10]. Shakespeare [10] applied short-time Fourier transform to DUS signals from fetal heart and carried out identification of fetal heart events such as valve and wall motions observed in Doppler signal as well as determination of relations between them.…”

Section: Discussionmentioning

confidence: 99%

Antepartum non-invasive evaluation of opening and closing timings of the cardiac valves in fetal cardiac cycle

Khandoker

Kimura

Ito

et al. 2009

Med Biol Eng Comput

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In this study, we propose a non-invasive algorithm to recognize the timings of fetal cardiac events on the basis of analysis of fetal ECG (FECG) and Doppler ultrasound signals. Multiresolution wavelet analysis enabled the frequency contents of the Doppler signals to be linked to the opening (o) and closing (c) of the heart's valves (Aortic (A) and Mitral (M)). M-mode, B-mode and pulsed Doppler ultrasound were used to verify the timings of opening and closure of these valves. In normal fetuses, the time intervals from Q-wave of QRS complex of FECG to opening and closing of aortic valve, i.e., Q-Ao and Q-Ac were found to be 79.3 +/- 17.4 and 224.7 +/- 13.3 ms, respectively. For the mitral valve, Q-Mc and Q-Mo were found to be 27.7 +/- 9.4 and 294.6 +/- 21.3 ms, respectively. Correlations among the timings in opening and closing of cardiac valves were found to be higher in abnormal fetuses than that in normal ones.

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“…2a) during a cardiac cycle (IRT%). IRT% is a simple reproducible index of isovolumic relaxation that can be assessed using noninvasive Doppler ultrasonography of the fetal heart [92,93]. A prolonged IRT is a sensitive marker of abnormal left ventricular relaxation in adults, and it is shown to be increased in fetuses with placental insufficiency [93].…”

Section: Isovolumic Relaxationmentioning

confidence: 99%

“…IRT% is a simple reproducible index of isovolumic relaxation that can be assessed using noninvasive Doppler ultrasonography of the fetal heart [92,93]. A prolonged IRT is a sensitive marker of abnormal left ventricular relaxation in adults, and it is shown to be increased in fetuses with placental insufficiency [93]. Alternative parameters suggested for non-invasive assessment of fetal left ventricular diastolic function include septum primium mobility, pulmonary vein pulsatility, left atrial shortening [94], and early myocardial relaxation velocity (Em) measured by TDI (Fig.…”

Section: Isovolumic Relaxationmentioning

confidence: 99%

The Fetal Cardiac Function

Acharya¹,

Räsänen²,

Kiserud³

et al. 2006

CCR

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Despite significant progress in the prenatal diagnosis of congenital heart disease and the postnatal management, the prenatal evaluation of fetal heart function remains difficult. The unique characteristics of the fetal circulation have a significant impact on its cardiac function. Commonly used physiological concepts about the function of the heart can be misleading when applied to the intrauterine situation. Most noninvasive parameters of cardiac function are not validated in the fetus. In addition, unlike structural defects that can be easily confirmed after delivery, functional hemodynamic abnormalities diagnosed in utero cannot be verified postnatally with certainty as the neonatal circulation defers considerably from the fetal circulation. This review attempts to describe commonly used methods of assessment of fetal cardiac function, their physiological basis and, their utility in clinical practice. THE FETAL CARDIAC FUNCTIONThe heart's main function is to deliver sufficient oxygenated blood to meet the metabolic requirements of the tissues [1]. The overall cardiac performance reflects the interaction of the heart, blood volume and blood vessels. The unique characteristics of the fetal circulation [2] have a significant impact on its cardiac function and distribution of cardiac output. The fetal circulation differs considerably from the adult and neonatal circulation. The placenta, a large extracorporal organ designed for disposal at birth, performs the functions of many organ systems in utero. Human placenta receives about 30% of the combined cardiac output [3,4] and the total peripheral resistance in the fetus is mainly determined by the placental-vascular resistance [5]. The placental volume blood flow normalized for fetal weight decreases with advancing gestation after 25 weeks [6].Both sides of the fetal heart under normal conditions have similar pressures [7] and work in parallel, and the fetal heart rate is much faster than the adult. As a result the weight-indexed combined cardiac output is higher in the fetus and the outputs of the left and right ventricles can be different. Right ventricular dominance develops towards term, and the output of the right ventricle constitutes about 60% of the combined cardiac output [8]. The parallel disposition of two ventricular pumps confers the aortic isthmus (Fig. 1), i.e. the vascular segment located between the origin of the left subclavian artery and the junction of the aorta with the ductus arteriosus, a special function of maintaining communication and balance between two parallel arterial outlets [9].The pulmonary circulation has a high vascular resistance and is sensitive to the changes in arterial pH and partial Fig. (1). Color Doppler image of fetal aorta demonstrating the isthmic area (arrow) and typical pulsed-wave (inverted) Doppler velocity waveforms (lower panel) obtained at the aortic isthmus in a near term fetus. A brief small reverse component during early diastole (arrow-head) is normal in late gestation.pressure of oxygen (PO 2 ) and carbon di...

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Assessment of fetal left cardiac isovolumic relaxation time in appropriate and small-for-gestational-age fetuses

Cited by 33 publications

References 13 publications

Intrauterine Growth Retardation and Fetal Cardiac Function

Intrauterine Growth Retardation and Fetal Cardiac Function

Antepartum non-invasive evaluation of opening and closing timings of the cardiac valves in fetal cardiac cycle

The Fetal Cardiac Function

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