Clinical aspects and physiopathology of fetal left heart hypoplasia. 2 case reports

2 cases of congenital hypoplastic left heart syndrome are presented with regard to clinical signs and pathophysiology. The hypoplastic left heart syndrome consists of a hypoplastic left ventricle and absence or atresia of the aortic valve, associated with severe hypoplasia of the ascending aorta and various degrees of mitral valve hypoplasia. Infants are well developed at birth but are unable to maintain sufficient circulation after physiologic closure of the ductus arteriosus.     

Assessment of the fetus: intermittent auscultation, electronic fetal heart rate tracing, and fetal pulse oximetry

Intrapartum assessment of fetal well-being has evolved over the last 40 years, with the primary focus being fetal heart rate assessments. Despite widespread use and initial enthusiasm for the potential for heart rate monitoring to reduce fetal and neonatal mortality and morbidity, conclusive evidence of improvement in long-term outcomes is lacking. Its use is associated with an increase in operative obstetric interventions and may increase morbidity associated with such interventions. Current investigation includes fetal pulse oximetry and further analysis of specific fetal electrocardiographic changes associated with hypoxic stress. Currently it is likely that fetal heart rate monitoring will maintain its role as a common intervention in obstetric units.     

Clinical significance of sinusoidal fetal heart rate pattern

Sinusoidal fetal heart rate pattern has been regarded as a sign of fetal jeopardy and 92 instances of this pattern were analysed. The morphologically different major and minor sinusoidal patterns were assessed with regard to their clinical significance as predictors of fetal compromise. There were 83 instances of minor sinusoidal pattern (amplitude of oscillation less than 25 beats/min) with only one antepartum fetal death. Major sinusoidal pattern (amplitude of oscillation greater than 25 beats/min) was diagnosed in nine patients and in six of them the fetus died before, during or after delivery. It is concluded that patients with minor sinusoidal heart rate patterns may be managed expectantly, whereas on the rare occasion when a major sinusoidal pattern is seen expeditious delivery is justified.     

Clinical significance of sinusoidal fetal heart rate pattern

Summary. Sinusoidal fetal heart rate pattern has been regarded as a sign of fetal jeopardy and 92 instances of this pattern were analysed. The morphologically different major and minor sinusoidal patterns were assessed with regard to their clinical significance as predictors of fetal compromise. There were 83 instances of minor sinusoidal pattern (amplitude of oscillation <25 beats/min) with only one antepartum fetal death. Major sinusoidal pattern (amplitude of oscillation >25 beats/min) was diagnosed in nine patients and in six of them the fetus died before, during or after delivery. It is concluded that patients with minor sinusoidal heart rate patterns may be managed expectantly, whereas on the rare occasion when a major sinusoidal pattern is seen expeditious delivery is justified.     

Problems in the detection of intrapartum fetal asphyxia with intermittent auscultation

We present 4 cases of severe intrapartum fetal asphyxia occurring during spontaneous unaugmented labours at term in low-risk women. In each case the baseline heart rate was completely normal, and the only indication of asphyxia was markedly decreased variability detected with electronic fetal heart rate monitoring. Correct action was taken in 3 cases that probably prevented fetal death or reduced neonatal morbidity. In no case would intermittent auscultation have been able to identify the compromised fetus.     

Perinatal management of pregnancies with severe fetal heart defects and epigenetic aspects

Objective: To describe pregnancies with severe fetal heart defects (CHD) with respect to perinatal complications and management. To discuss epigenetic factors with respect to maternal body mass index (BMI) and assisted reproduction treatment (ART). Methods: We performed a retrospective analysis in a single centre for prenatal diagnostics. Data were collected with respect to pre- and postnatal diagnoses of CHD, preterm labour and deliveries, maternal risk factors and postnatal outcome. Results: Between 2009 and 2011 we treated 116 patients with severe fetal heart defects. Prenatal diagnoses were: Hypoplastic left heart syndrome (HLHS) in 50 fetuses (43.1%), conotruncal heart defects (CTM) in 43 (37.1%), atrial ventricular septal defects in eight cases (7.8%).There were 11 (9.9%) twin pregnancies. Premature labour occurred in 11.2%, premature deliveries 12.9%. Nine pregnancies (7.8%) were achieved by assisted reproduction treatment (ART). A body mass index (BMI) > 25 occurred in 54.3% with 3% morbid obesity. Advanced maternal age >35 was found in 33.5%. Accuracy of the prenatal diagnosis was 97%. Conclusions: Patients with ART pregnancies may be referred to fetal echocardiography. Maternal obesity poses a diagnostic problem, the incidence of CTM may be higher due to epigenetic factors. This requires further studies. As premature labour and delivery is a frequent complication, perinatal management of these pregnancies must be reserved to specialized centers.     

Fetal heart rate auscultation: current and future practice

Intermittent auscultation (IA) has been reported as equivalent to electronic fetal monitoring (EFM) as a fetal surveillance method in terms of neonatal outcomes based on randomized controlled trials and meta-analyses. Despite recommendations to include IA as a primary method for fetal evaluation, EFM use predominates. Understanding the equipment, method, benefits and limitations, and strategies for implementing IA may assist nurses in providing informed choices for low-risk pregnant women.     

Fetal heart rate pattern recognition by the method of auscultation

The thesis that obstetric health care personnel can discriminate characteristics of baseline fetal heart rate (FHR) and FHR patterns by auscultation needs to be tested. For this study, audiotones of the FHR signals were recorded for eight representative FHR patterns. Each recording was for three minutes and included one uterine contraction. Physicians and nurses who use continuous electronic FHR monitoring on a regular basis listened to the eight recordings and attempted to identify the baseline rate, variability, and periodic patterns, and then matched their perceptions with the eight corresponding FHR tracings (not in order). Baseline FHR and FHR without periodic patterns were most frequently identified correctly. Late decelerations with and without good baseline variability were misdiagnosed 18.4 and 33% of the time, respectively. Although the FHR characteristics and periodic patterns were correctly identified most of the time, failure to recognize significant periodic patterns by as many as one-third of the participants is unacceptable in modern obstetrics.