Maternal obesity affects fetal myocardial function as early as in the first trimester.

OBJECTIVE: To investigate cardiac function from 14 weeks' gestation in fetuses of obese pregnant women (FOW). Animal studies have shown that maternal obesity induces fibrosis in fetal myocardium. We hypothesized that fetal cardiac function would be impaired among FOW. METHODS: A case-control study with longitudinal follow-up was performed at Trondheim University Hospital, Norway. In total, 80 pregnant women were included and the final population comprised 52 obese and 24 of normal weight (mean body mass index before pregnancy, 34.8 ± 4.1 vs 21.0 ± 2.2 kg/m(2) ; P < 0.001). The main outcome measures were global strain rate (GSR) and strain by tissue Doppler imaging, tissue Doppler velocities (TDVs) and interventricular septal thickness assessed by fetal echocardiography at gestational ages of 14, 20 and 32 weeks. RESULTS: In FOW, fetal left ventricle (LV) and right ventricle (RV) GSR and strain were significantly lower than in fetuses of normal-weight pregnant women: LV GSR was 33.3% lower at 14 weeks, 22.4% lower at 20 weeks and 22.8% lower at 32 weeks of gestation (P < 0.001) with no difference in fetal heart rate. Systolic and late diastolic TDVs for LV were significantly lower from 20 weeks' gestation and remained lower throughout pregnancy. Fetal interventricular septum was 26.6% (P < 0.001) thicker in late pregnancy in FOW compared with normal-weight pregnancies. CONCLUSIONS: At 14 weeks of gestation, we detected fetal myocardial dysfunction with reduced LV and RV GSR and strain in FOW compared with fetuses of women with normal weight. Our finding is alarming considering the high prevalence of obesity and may partly explain the predisposition of offspring to cardiovascular disease later in life.

The examiner's ultrasound experience has a significant impact on the detection rate of congenital heart defects at the second-trimester fetal examination.

OBJECTIVES: To determine whether training and experience in performing ultrasound examinations are factors that influence the prenatal detection of congenital heart defects (CHDs) in a non-selected population, in order to evaluate and improve the current training program. METHODS: All pregnant women who received a routine second-trimester ultrasound scan by a sonographer/midwife and delivered at our hospital between February 1991 and December 2001 were registered prospectively. Less experienced sonographer/midwives who had performed between 200 and 2000 routine examinations were compared with experienced sonographer/midwives who had carried out more than 2000 examinations. During the first 5 years of the study the heart structures obtained were registered in detail. RESULTS: Of 29,035 fetuses, 35/82 (43%) major CHDs were prenatally detected at the routine examination. The experienced sonographer/midwives obtained both the four-chamber view and the great arteries in 75%; the figure for the less experienced sonographer/midwives was 36% (P < 0.001). The differences in detecting major heart defects were 22/42 (52%) and 13/40 (32.5%), isolated CHDs 8/18 (44%) and 6/22 (27%) and CHDs with associated malformations 14/24 (58%) and 7/18 (39%), respectively. In both groups some CHDs with an abnormal four-chamber view were missed, although the experienced sonographer/midwives recognized significantly more of the abnormal views than did the less experienced sonographer/midwives (P = 0.002). CONCLUSIONS: Experience has a significant impact on the examination of the fetal heart and the prenatal detection rate of major CHDs. To avoid a relatively long learning curve, ultrasound education needs to intensify the teaching of the basic four-chamber view. The great arteries should be included after additional training. Those basic views of the fetal heart must be mastered before new views and advanced technology are added to the fetal heart examination.

Prenatal detection of heart defects in a non-selected population of 30,149 fetuses--detection rates and outcome.

OBJECTIVES: To evaluate the detection rate of congenital heart defects (CHD) in a non-selected population and to follow outcome after diagnosis. METHODS: All 30,149 fetuses/newborns that were scheduled to deliver at our hospital between February 1991 and December 2001 were registered prospectively. Of these, 29,460 (98%) fetuses had a prenatal ultrasound scan at our center. The routine fetal examination at approximately 18 weeks' gestation included the four-chamber view and the great arteries of the fetal heart. The follow-up period was 2-13 years. RESULTS: Of 97 major CHDs, 55 (57%) were detected prenatally, 16% (9/55) prior to, 66% (36/55) at and 18% (10/55) after the routine scan. Forty-four percent (19/43) of the isolated CHDs, 67% (36/54) of those with associated malformations and 48% (11/23) of the isolated ductal-dependent CHDs were detected. Thirty-eight percent (37/97) had an abnormal karyotype. Of the 55 major CHDs detected, 44% (24) of the pregnancies with lethal/serious fetal malformations were terminated, 15% (8) died in utero, 42% (23) were born alive and 27% (15) were still alive after 2 years. Of the 42 CHDs detected postnatally, 2% (1) were terminated for other reasons, 98% (41) were born alive and 81% (34) were still alive after 2 years. CONCLUSIONS: Prenatal detection of CHD is still a challenge, with a 57% detection rate only. Isolated defects are detected less frequently. The overall outcome suggests that the most severe defects are detected with the present screening setting; only 27% of the babies with major CHDs detected were still alive after 2 years. Data from long-term follow-up will be of importance for the counseling process.

Tissue Doppler gated (TDOG) dynamic three-dimensional ultrasound imaging of the fetal heart.

Dynamic three-dimensional (3D) ultrasound imaging of the fetal heart is difficult due to the absence of an electrocardiogram (ECG) signal for synchronization between loops. In this study we introduce tissue Doppler gating (TDOG), a technique in which tissue Doppler data are used to calculate a gating signal. We have applied this cardiac gating method to dynamic 3D reconstructions of the heart of eight fetuses aged 20-24 weeks. The gating signal was derived from the amplitude and frequency contents of the tissue Doppler signal. We used this signal as a replacement for ECG in a 3D-volume reconstruction and visualization, utilizing techniques established in ECG-gated 3D echocardiography. The reliability of the TDOG signal for fetal cardiac cycle detection was experimentally investigated. Simultaneous recordings of tissue Doppler of the heart and continuous wave (CW) spectral Doppler of the umbilical artery (UA) were performed using two independent ultrasound systems, and the TDOG signal from one system was compared to the Doppler spectrum data from the other system. Each recording consisted of a two-dimensional (2D) sector scan, transabdominally and slowly tilted by the operator, covering the fetal heart over approximately 40 cardiac cycles. The total angle of the sweep was estimated by recording a separate loop through the center of the heart, in the elevation direction of the sweep.3D reconstruction and visualization were performed with the EchoPAC-3D software (GE Medical Systems). The 3D data were visualized by showing simultaneous cineloops of three 2D slices, as well as by volume projections running in cineloop. Synchronization of B-mode cineloops with the TDOG signal proved to be sufficiently accurate for reconstruction of high-quality dynamic 3D data. We show one example of a B-mode recording with a frame rate of 96 frames/s over 20 seconds. The reconstruction consists of 31 volumes, each with 49 tilted frames. With the fetal heart positioned 5-8 cm from the transducer, the sampling distances were approximately 0.15 mm in the beam direction, 0.33 degrees approximately 0.37 mm azimuth and 0.45 degrees approximately 0.51 mm elevation. From this single dataset we were able to generate a complete set of classical 2D views (such as four-chamber, three-vessel and short-axis views as well as those of the ascending aorta, aortic and ductal arches and inferior and superior venae cavae) with high image quality adequate for clinical use.

Comparison of prenatal ultrasound and postmortem findings in fetuses and infants with congenital heart defects.

OBJECTIVE: Detection of congenital heart defects by prenatal ultrasound examination has been one of the great challenges since the investigation for fetal anomalies became part of the routine fetal examination. This prospective study was designed to evaluate the concordance of prenatal ultrasound findings with autopsy examination in a population consisting of both referred women and non-selected pregnant women. DESIGN: Criteria for inclusion were an ultrasound examination at the National Center for Fetal Medicine and an autopsy performed during the years 1985-94. Results from the ultrasound and autopsy examinations were systematized into categories depending on the degree of concordance. RESULTS: Of 408 infants and fetuses with developmental anomalies, 106 (26%) had congenital heart defects. In 63 (59%) of these 106 cases, the heart defect was the principal reason for the termination of pregnancy or the cause of death. Excluding five cases with a secundum atrial septal defect, there was complete agreement between the ultrasound examination and the autopsy findings in 74 (73%) of 101 cases. In 18 cases, there were minor discrepancies between ultrasound and autopsy findings. The main diagnosis was thus correct in 92 cases (91%). From the first time period (1985-89) to the second (1990-94), the detection rate of all heart defects increased from 48% to 82%. CONCLUSION: This study confirms a good correlation between ultrasound and autopsy diagnoses in fetuses and infants with congenital heart defects. A significant improvement in the detection of heart defects occurred from the first time period to the second and was probably due to increased experience and technical advances.

Prenatal detection of heart defects at the routine fetal examination at 18 weeks in a non-selected population.

Few studies have addressed the prenatal detection rate of congenital heart defects in a non-selected population at 18 weeks of gestation. Our objective was to assess the change in the prenatal detection rate of congenital heart defects in such a population that resulted from incorporating the four-chamber view at the second-trimester routine ultrasound examination. The prenatal detection rate of heart defects was prospectively compared between 4435 fetuses in Phase I who were scanned without special attention to the heart, and 7459 fetuses in Phase II who were scanned incorporating the four-chamber view. Of the 49 heart defects in Phase 1, 17 (35%) were critical and three (18%) of these were detected prenatally. Of the 90 heart defects in Phase II, 23 (26%) were critical, six (26%) of these were detected prenatally at the 18 weeks' routine scan, and three were detected in the third trimester, providing a total prenatal detection rate of 39%. A defect was classified as critical when a surgical repair was likely to be required because of gross structural complexity having a functional significance, e.g. transposition of the great arteries, hypoplastic left heart syndrome, atrioventricular septal defect, coarctation of the aorta, and large ventricular septal defect. No non-critical heart defects were detected prenatally in either of the phases. The incidences in the total population were 11 and 12/1000 in Phases I and II, respectively. Thirty-two per cent of the critical and 16% of the non-critical defects had associated abnormalities and/or abnormal karyotype.(ABSTRACT TRUNCATED AT 250 WORDS)

Incorporating the four-chamber view of the fetal heart into the second-trimester routine fetal examination.

The four-chamber view of the fetal heart is reported to he the most useful view for detecting congenital heart defects. In 7322 non-selected, consecutive pregnancies of women attending a second-trimester (18 weeks) routine ultrasound scanning program, we examined our ability to obtain a four-chamber view in the fetus within the 30 min generally allocated to do the scan and record data. Five trained nurse-midwives performed the examinations between June 1988 and September 1990. In the first part of the study, a four-chamber view could not be obtained in 7%, while in the second part, the failure rate was 4%, which showed a learning effect over time. The demonstration of a four-chamber view was significantly better with a 5 MHz than with a 3.5 MHz transducer. The ability to obtain the four-chamber view improved as the gestational age increased. The main reason for not being able to obtain the four-chamber view with the 3.5 MHz transducer was poor imaging; for the 5 MHz transducer, it was an unfavorable position of the fetus. Education and experience, as well as good equipment, are important factors in obtaining good results. The time spent learning to obtain a four-chamber view reliably was relatively long.