Doppler Echocardiographic Evaluation of Left Ventricular Output and Left Ventricular Diastolic Filling Changes in the First Day of Life

Abstract

MATERIALS AND METHODSThe loading condition of the left ventricle changes markedly during the transition from fetal to neonatal circulation and continues to be unstable shortly after birth. During this period, pulmonary blood flow, which acts as preload to the left ventricle, increases because of left-to-right ductus arteriosus shunting (I, 2). Among the hemodynamic factors affecting left ventricular diastolic filling, preload appears to play an important role, as has been recently suggested (3,4). Interest has more recently been directed toward the possibility of using Doppler echocardiography to assess left ventricular diastolic hemodynamics in the early neonatal period (5-8). However, the impact of changes in preload on the transmitral flow pattern in neonates is as yet unclear. The purpose of our study was to evaluate by Doppler echocardiography the serial changes of left ventricular filling patterns in normal neonates during their transition to postnatal circulation.Study population. The study population consisted of20 normal term neonates. Their mothers had uncomplicated pregnancies with no evidence of toxemia, diabetes mellitus, or pregnancyinduced hypertension. None of the infants were acutely ill or showed any evidence of congenital malformations. The mean birth weight was 3068 ± 351 g (mean ± SD), and the mean gestational age was 39 ± I wk. Each mother received an explanation of the study and gave informed consent. Serial echocardiographic examinations were performed on each subject at 2, 12, and 24 h after birth.Examination technique. A complete two-dimensional echocardiographic examination was performed on the subjects with an Aloka SSD 870 ultrasonoscope with a 5.0-MHz transducer. The size of the Doppler sample volume was set at an axial length of 2 mm, with a wall filter setting of 400 Hz. All neonates were examined while they were lying quietly in the supine position breathing room air. To record the transmitral flow velocity profile, a standard apical two-chamber view was visualized, and the Doppler sample volume was placed in the inflow area of the left ventricle just below the level of the mitral annulus, adjusted to record the maximal flow velocities. The ascending aortic flow was measured from the suprasternal long axis view. The sample volume was placed in the AO immediately distal to the aortic valve. Care was taken to carry out these studies with the transducer beam as close to parallel to the presumed blood flow direction as possible. Because the angle between the estimated direction of blood flow and the Doppler beam was 20 degrees or less in the selected planes, no angle correction of the Doppler signal was made. All examinations were recorded at a paper speed of 100 mm/s, The electrocardiogram and respiration of each subject (with a pressure transducer placed against the abdominal wall) were simultaneously recorded. With the aid of a computer-interfaced digitizer pad (Cardio 500, Kontron Medical System), the various Doppler flow indices were measured from 506 Abbreviations AD, ascendin...

Left Ventricular Contractile State of Early Human Neonates with Patent Ductus Arteriosus.

“…Similar to the other Doppler studies (Drayton and Skidmore 1987; Agata et al 1991), we previously demonstrated that the left-to-right ductal shunt increased at 2 hr of age and decreased rapidly by 12 hr of age (Harada et al 1994). In the present study, the left atrial to aortic root ratio and the inner diameter of the ductus arteriosus significantly increased in group 1 (mean age 1.8 hr after birth) compared with group 2 (mean age =13.0 hr after birth), thus the LV preload was suggested to be higher in group 1 than group 2.…”

Right Ventricular Diastolic Filling in the First Day of Life.

“…Among the hemodynamic factors affecting left and right ventricular diastolic filling, preload appears to play an important role, as documented by recent studies (Choong et al 1987; Courtois et al 1988; Triulzi et al 1990; Odake et al 1991;Castini et al 1992). We have demonstrated the effects of a patent ductus arteriosus on left ventricular diastolic filling (Harada et al 1994) However, the impact of changes in preload on the transtricuspid flow pattern in this period is less clear. The purpose of our present study was to evaluate the serial changes of right ventricular filling patterns in normal neonates during their transition to postnatal circulation.…”

“…Choong et al (1987) reported that nitroglycerin altered the Doppler characteristics of the early filling wave. We have previously demonstrated the effects of ductus arteriosus on the left ventricular diastolic filling (Harada et al 1994), however, little attention has been paid to right ventricular diastolic filling in the early neonatal period. To our knowledge, this is the first serial evaluation of the relation between right ventricular output changes and right ventricular diastolic filling changes in normal human subjects during the early neonatal period.…”

Current Application of Functional/Targeted Echocardiogram in NICU: An Update

“…Transmitral VTI can be measured to give an estimate of flow across the atrioventricular valves. 21 The Tei index (or myocardial performance index) has been found to be a valuable quantitative echocardiography index of ventricular function by incorporating both systolic and diastolic performance of the right and left ventricles (Fig.-4). It is defined as the sum of isovolumetric contraction and relaxation times divided by the ejection time, which requires measurement of the time interval between the end and onset of mitral or tricuspid inflow (the 'a' interval) and the ejection time of the LV or RV outflow (the 'b' interval).…”