Myocardial ischaemia in asphyxia neonatorum. Electrocardiographic, enzymatic and histological correlations

Normal values of creatine kinase and of MB-creatine kinase at birth in healthy babies

BACKGROUND

Today, few studies have been accomplished in order to determine serum creatine kinase (CK) activity in newborns by considering small groups of babies and without taking into account gestational age (GA) differences. Some authors have demonstrated that neonatal CK activity value at birth is higher than the normal range of CK activity considering for adults or older children. The objective of this study is to assess normal values of CK and MB-CK in neonatal blood, according to babies' GA.

METHODS

We retrieved the clinical files of 140 babies admitted into Siena Hospital NICU in a 2-years period, when CK was assessed routinely to all babies at birth. We selected files from 114 newborns and we divided the cohort into group A (non-stressed; N.=41) and group B (stressed; N.=73) on the basis of Apgar Score and signs of neurological lesions. We compared CK and MB-CK values in the two groups according to GA.

RESULTS

Mean CK value of the 41 non-stressed babies' samples: 413 IU/L (232 SD). CK significantly increases with GA. No differences are present in total CK activity between stressed vs. non-stressed babies; but a significant difference appears in these two groups for MB-CK (mean values: 456 vs. 175 IU/L).

CONCLUSIONS

This is the first study that compares CK and MB-CK values at birth according to the GA of the babies. CK values increase with GA, and stressed babies have higher MB-CK values than the non-stressed babies. These reference values are important for clinical practice.

Application of Neonatologist Performed Echocardiography in the Assessment and Management of Neonatal Heart Failure unrelated to Congenital Heart Disease

Neonatal heart failure (HF) is a progressive disease caused by cardiovascular and non-cardiovascular abnormalities. The most common cause of neonatal HF is structural congenital heart disease, while neonatal cardiomyopathy represents the most common cause of HF in infants with a structurally normal heart. Neonatal cardiomyopathy is a group of diseases manifesting with various morphological and functional phenotypes that affect the heart muscle and alter cardiac performance at, or soon after birth. The clinical presentation of neonates with cardiomyopathy is varied, as are the possible causes of the condition and the severity of disease presentation. Echocardiography is the selected method of choice for diagnostic evaluation, follow-up and analysis of treatment results for cardiomyopathies in neonates. Advances in neonatal echocardiography now permit a more comprehensive assessment of cardiac performance that could not be previously achieved with conventional imaging. In this review, we discuss the current and emerging echocardiographic techniques that aid in the correct diagnostic and pathophysiological assessment of some of the most common etiologies of HF that occur in neonates with a structurally normal heart and acquired cardiomyopathy and we provide recommendations for using these techniques to optimize the management of neonate with HF.

Integrated Evaluation of Neonatal Hemodynamics Program Optimizing Organ Perfusion and Performance in Critically Ill Neonates, Part 1: Understanding Physiology of Neonatal Hemodynamics

Integrated evaluation of neonatal hemodynamics is the integration of information obtained by echocardiography, clinical evaluation, and biochemical markers, in addition to the clinical information obtained from noninvasive and invasive monitoring of blood pressure and arterial and tissue oxygenation, leading to the formulation of a medical recommendation. This review will focus on the physiology of cardiovascular dynamics and oxygen delivery.

The diagnostic value of both troponin T and creatinine kinase isoenzyme (CK-MB) in detecting combined renal and myocardial injuries in asphyxiated infants

Background

Troponin T (cTnT) and Creatinine Kinase Isoenzyme (CK-MB) are both markers of myocardial injuries. However, CK-MB is also elevated in acute kidney injury.

Objective

The diagnostic value of both cTnT and cardiac CK-MB in combined myocardial and acute kidney injuries (AKI) in asphyxiated neonates was evaluated.

Method

40 asphyxiated infants and 40 non-asphyxiated controls were consecutively recruited. Serum levels of cTnT, CK-MB and creatinine were measured. Myocardial injury and AKI were defined as cTnT >95^th percentile of the control and serum creatinine >1.0 mg/dl respectively.

Results

Of the 40 subjects, 9 (22.50%), 8 (20.00%) and 4 (10.00%) had myocardial injury, AKI and combined AKI and myocardial injuries respectively. The mean cTnT and CK-MB values were highest in infants with combined AKI and myocardial injuries. The Mean cTnT in infants with AKI, myocardial injury and combined AKI and myocardial injuries were 0.010±0.0007 ng/ml, 0.067±0.040 ng/ml and 0.084±0.067 ng/ml respectively, p = 0.006. The mean CK-MB in infants with AKI, myocardial injury and combined AKI and myocardial injuries were 2.78±0.22 ng/ml, 1.28±0.11 ng/ml and 4.58±0.52 ng/ml respectively, p = <0.0001.

Conclusion

In severe perinatal asphyxia, renal and myocardial injuries could co-exist. Elevated cTnT signifies the presence of myocardial injury. Elevated CK-MB indicates either myocardial injury, AKI or both. Therefore renal injury should be excluded in asphyxiated infants with elevated CK-MB.

Xanthine oxidase and the fetal cardiovascular defence to hypoxia in late gestation ovine pregnancy

Hypoxia is a common challenge to the fetus, promoting a physiological defence to redistribute blood flow towards the brain and away from peripheral circulations. During acute hypoxia, reactive oxygen species (ROS) interact with nitric oxide (NO) to provide an oxidant tone. This contributes to the mechanisms redistributing the fetal cardiac output, although the source of ROS is unknown. Here, we investigated whether ROS derived from xanthine oxidase (XO) contribute to the fetal peripheral vasoconstrictor response to hypoxia via interaction with NO-dependent mechanisms. Pregnant ewes and their fetuses were surgically prepared for long-term recording at 118 days of gestation (term approximately 145 days). After 5 days of recovery, mothers were infused i.v. for 30 min with either vehicle (n = 11), low dose (30 mg kg(-1), n = 5) or high dose (150 mg kg(-1), n = 9) allopurinol, or high dose allopurinol with fetal NO blockade (n = 6). Following allopurinol treatment, fetal hypoxia was induced by reducing maternal inspired O2 such that fetal basal P aO 2 decreased approximately by 50% for 30 min. Allopurinol inhibited the increase in fetal plasma uric acid and suppressed the fetal femoral vasoconstrictor, glycaemic and lactate acidaemic responses during hypoxia (all P < 0.05), effects that were restored to control levels with fetal NO blockade. The data provide evidence for the activation of fetal XO in vivo during hypoxia and for XO-derived ROS in contributing to the fetal peripheral vasoconstriction, part of the fetal defence to hypoxia. The data are of significance to the understanding of the physiological control of the fetal cardiovascular system during hypoxic stress. The findings are also of clinical relevance in the context of obstetric trials in which allopurinol is being administered to pregnant women when the fetus shows signs of hypoxic distress.

Heart Rate and Arterial Pressure Changes during Whole-Body Deep Hypothermia

Whole-body deep hypothermia (DH) could be a new therapeutic strategy for asphyxiated newborn. This retrospective study describes how DH modified the heart rate and arterial blood pressure if compared to mild hypothermia (MH). Fourteen in DH and 17 in MH were cooled within the first six hours of life and for the following 72 hours. Hypothermia criteria were gestational age ≥36 weeks; birth weight ≥1800 g; clinical signs of moderate/severe hypoxic-ischemic encephalopathy. Rewarming was obtained in the following 6-12 hours (0.5°C/h) after cooling. Heart rates were the same between the two groups; there was statistically significant difference at the beginning of hypothermia and during rewarming. Three babies in the DH group and 2 in the MH group showed HR < 80 bpm and QTc > 520 ms. Infant submitted to deep hypothermia had not bradycardia or Qtc elongation before cooling and after rewarming. Blood pressure was significantly lower in DH compared to MH during the cooling, and peculiar was the hypotension during rewarming in DH group. Conclusion. The deeper hypothermia is a safe and feasible, only if it is performed by a well-trained team. DH should only be associated with a clinical trial and prospective randomized trials to validate its use.

Electrocardiographic and enzymatic correlations with outcome in neonates with hypoxic-ischemic encephalopathy

Background

Perinatal asphyxia leading to hypoxic-ischemic encephalopathy (HIE) is a common problem causing multi organ dysfunction including myocardial involvement which can affect the outcome.

Objective

To evaluate the myocardial dysfunction in neonates having HIE by electrocardiographic(ECG) and cardiac enzymes (CK Total, CK-MB and Troponin I) and find out the relationship with HIE and outcome.

Design/Methods

This was a hospital based prospective study. Sixty term neonates who had suffered perinatal asphyxia and developed HIE were enrolled. Myocardial involvement was assessed by clinical, ECG, and CK Total, CK-MB and Troponin I measurements.

Results

Of 60 cases, 13(21.7%) were in mild, 27(45%) in moderate and 20(33.3%) belonged to severe,HIE. ECG was abnormal in 46 (76.7%); of these 19 (41.3%) had grade I, 13 (28.2%) grades II and III each and 1 (2.1%) with grade IV changes. Serum levels of CK Total, CK- MB and Troponin I were raised in 54 (90%), 52 (86.6%) and 48 (80%) neonates, respectively. ECG changes and enzymatic levels showed increasing abnormalities with severity of HIE, and the differences among different grades were significant (p = 0.002, 0.02, <0.001 and 0.004, respectively). Nineteen (32%) cases died during hospital stay. The non- survivors had high proportion of abnormal ECG (p = 0.024), raised levels of CK-MB (p = 0.018) and Troponin I (p = 0.008) in comparison to survivors.

Conclusions

Abnormal ECG and cardiac enzymes levels are found in HIE and can lead to poor outcome due to myocardial damage Early detection can help in better management and survival of these neonates.

Myocardial performance assessment in neonates by one-segment strain and strain rate analysis by tissue Doppler - a quality improvement cohort study

OBJECTIVES

To investigate one-segment strain and strain rate indices as measures of myocardial performance in asphyxiated term neonates.

DESIGN

Quality improvement cohort study.

SETTING

Newborns admitted to a neonatal intensive care unit at a Norwegian University Hospital for perinatal asphyxia and non-asphyxiated newborn recruited from the maternity ward at the same hospital.

PARTICIPANTS

Twenty asphyxiated and 48 non-asphyxiated term neonates.

PRIMARY OUTCOME MEASURE

Strain and strain rate indices and repeatability measures. One-segment longitudinal strain and strain rate by tissue Doppler were assessed on days 1, 2 and 3 of life in nine heart walls. Repeatability was compared against measurements from two-segment analyses previously performed in the same images.

RESULTS

The 95% limits of agreement were significantly better for the one-segment than two-segment repeatability analyses, the inter-rater peak systolic strain (PSS) was (-3.1, 3.3) vs (-11.4, 18.3)%, the inter-rater peak systolic strain rate (PSSR) was (-0.38, 0.40) vs (-0.79, 1.15)/s, the intra-rater PSS was (-2.5, 2.6) vs (-8.0, 9.8)% and the intra-rater PSSR was (-0.23, 0.25) vs (-0.75, 0.80)/s (p<0.05). The myocardial performance was lower in the asphyxiated neonates (indices closer to zero) than in the non-asphyxiated neonates, PSS was -17.8 (0.6) (mean (SEM)) vs -21.2 (0.3)%, PSSR -1.43 (0.08) vs -1.61 (0.03)/s, early diastolic strain rate 1.72 (0.11) vs 2.00 (0.11)/s and strain rate during the atrial systole 1.92 (0.17) vs 2.27 (0.10)/s (p<0.05), despite no difference in fractional shortening (29.0 (0.5) vs 29.1 (1.0)%) (p>0.05).

CONCLUSIONS

One-segment strain and strain rate assessed the reduced myocardial performance in asphyxiated neonates with significantly improved reproducibility as compared with two-segment analysis and was therefore more feasible than two-segment analyses for assessment of myocardial performance after perinatal asphyxia.

Shock: a common consequence of neonatal asphyxia

Neonatal asphyxia is associated with multi-organ hypoxia-ischemia and subsequent dysfunction. The cardiovascular system is frequently affected, causing signs of shock and complicating the neonatal circulatory transition. Hypothermia therapy can improve outcome from neonatal asphyxia without adversely affecting cardiovascular stability. Therapy directed at the cardiovascular system can improve short-term measures of systemic blood flow, but to date has not been demonstrated to improve long-term outcome.

Longitudinal strain and strain rate by tissue Doppler are more sensitive indices than fractional shortening for assessing the reduced myocardial function in asphyxiated neonates

The function of the heart was studied in 20 asphyxiated term neonates by measuring the longitudinal peak systolic strain and peak systolic strain rate by tissue Doppler in 18 segments of the heart on days 1, 2, and 3 of life. The fractional shortening was assessed at each examination as well. Measurements were compared against measurements in 48 healthy term neonates examined by the same protocol. The function of the heart was lower in the asphyxiated neonates - peak systolic strain (mean (95% confidence interval) -19.4% (-20.4, -18.5), peak systolic strain rate -1.65 (-1.74, -1.56) per second) than in the healthy term neonates (peak systolic strain -21.7% (-22.3, -21.0), peak systolic strain rate -1.78 (-1.84, -1.74) per second; p < 0.001). Fractional shortening was similar in the asphyxiated (29.2% (26.8, 31.5)) and healthy term neonates (29.0% (27.9, 30.1); p = 0.874). The peak systolic strain differed significantly between the asphyxiated and healthy term neonates for the left basal and right basal groups of segments (p < 0.05) but not for the left apical, right apical, septum apical, or septum basal groups of segments. The peak systolic strain rate differed significantly only for the septum apical group of segments. The differences were largest on the second day of life. Measurements were similar in asphyxiated neonates with elevated and normal cardiac troponin T levels. The peak systolic strain and strain rate were in this study more sensitive indices than fractional shortening for assessing the reduced myocardial function in asphyxiated term neonates.

Systemic complications and hypothermia

Cooling for neonatal hypoxic-ischemic encephalopathy is a novel and promising neuroprotective therapy that requires significant understanding of how cooling affects all organ systems and interventions used to treat systemic complications of cooling in an intensive care setting. As cooling is used more widely and has been newly introduced in neonatal units, continued surveillance of its use in clinical practice is mandatory. Units offering cooling should strongly consider joining a registry (e.g. the Vermont-Oxford Neonatal Encephalopathy Registry in the USA or the TOBY Register in the UK) that facilitates benchmarking of short-term adverse effects and long-term outcomes of cooling and that supports local quality improvement efforts.

[Cardiac troponin as biochemical marker of perinatal asphyxia and hypoxic myocardial injury]

BACKGROUND/AIM

Myocardial cell lesion in newborns may be clinically occult. In recent years there has been shown growing interest in the use of cardiac troponin-I (cTnI) in relation to perinatal asphyxia and hypoxic myocardial lesion. The aim of this study was to determine a relationship between high cTnI levels and outcome in critically ill newborns with perinatal asphyxia.

METHODS

In this study 78 patients were divided into three groups. The group I included 39 newborns (15 term and 24 preterm) with perinatal asphyxia, with no deaths, only full or partial (with some neurological sequels) recovery. The group II included 10 newborns (6 preterm and 4 term), with perinatal asphyxia who died, with critical cardio-respiratory problems and multiorgan dysfunction. The group III included 29 healthy term newborns. A level of cTnI in all three groups was measured within 24-48 hours after delivery.

RESULTS

A statistically significant higher value of cTnI (0.082 microg/l +/- 0.166) was found in group I than in the group III (healthy newborns). In the group I, 21/39 newborns required respiratory and 16/39 required pressure support. In the group II, the largest average value of cTnI of 0.425 +/- 0.307 was found. All of the newborns in the group II required respiratory and pressure support. In the group III the lowest average value of cTnI (0.0186 microg/L +/- 0.0286) was found.

CONCLUSIONS

High cTnI levels could be used as markers of perinatal asphyxia and even as predictors of future outcomes and/or mortality.

Correlation of troponin I with perinatal and neonatal outcomes in neonates with respiratory distress

BACKGROUND

The specific aims of the present study were to evaluate the associations between cardiac troponin I (Tn I) and perinatal events and whether Tn I serves as a predictor to evaluate neonatal outcomes.

METHODS

Tn I level was assessed in sick neonates with respiratory distress within 12 h after birth. Apgar scores, acidosis, ventilator or oxygen requirement, hospital days and placenta clues were recorded. A total of 80 sick neonates were enrolled (54 preterm and 26 full-term neonates) delivered at Shin-Kong Wu Ho-Su Memorial Hospital between July 2003 and December 2004.

RESULTS

There was a significant negative correlation between Apgar scores at 1 min and 5 min (r=-0.383, P= 0.001; r=-0.500, P < 0.001), acidosis (r=-0.309, P= 0.006), base excess (r=-0.332, P= 0.003) and Tn I. The subjects were divided into two groups using the median level of 0.028 ng/mL as a cut-off. There were significantly fewer neonates with high Apgar score (>7 at 5 min; 27/40, 69.2% vs 38/40, 97.4%; P= 0.001) in the higher Tn I group (> or =0.028 ng/mL). Lower pH (7.4 +/- 0.10 vs 7.3 +/- 0.1, P= 0.011), lower base excess (-1.0 +/- 4.3 vs -4.4 +/- 5.1, P= 0.003) and less placental weight (548.8 +/- 195.36 g vs 396.56 +/- 154.30 g, P= 0.019) were also seen in the higher Tn I group.

CONCLUSION

Tn I may play a role in the assessment of perinatal outcomes but is not a precise predictor of neonatal outcomes. Tn I level of 0.028 ng/mL is also suggested as a predictor of severity of perinatal outcomes in neonates with respiratory distress.

Risk of low Apgar score and socioeconomic position: a study of Swedish male births

Aim

The aim of this study was to investigate the association between maternal socioeconomic position and a persistent low Apgar score (a score of < 7 at 1 and 5 min following birth).

Methods

The research is based on a population cohort study of 183 637 males born in Sweden between 1973 and 1976. Data from the Medical Birth Register were linked to Population and Housing Censuses.

Results

There was evidence that mothers working in non-manual (Odds ratio (OR) 0.83 (0.72–0.97)) and self-employed (OR 0.64 (0.44–0.93)) occupations were less likely to have an infant with a low Apgar score, compared to manual workers. There was evidence that the risk of a low Apgar score decreased as the mother's level of education increased, if the infant was born by instrumental (OR 0.86 (0.74–0.99)) or caesarean section (OR 0.80 (0.68–0.93)) delivery, but not by unassisted vaginal delivery (OR 1.01 (0.92–1.10)).

Conclusion

There was a lower risk of poor birth condition in male infants born to more educated and non-manual/self-employed mothers. These differences may contribute to our understanding of socioeconomic differences in infant health and development although the results may not be applicable due to changes over the last 30 years.

Serum troponin in neonatal intensive care

Cardiac troponins have a major role in screening and diagnosis of myocardial ischaemia in adults and children. Their introduction has redefined the diagnosis of myocardial infarction in adults and provided valuable prognostic information. In the paediatric population, troponins show a good correlation with the extent of myocardial damage following cardiac surgery and cardiotoxic medication, and can be used as predictors of subsequent cardiac recovery and mortality. This review discusses the current established reference values in term and preterm infants and demonstrates their potential use in neonatology. They may serve as a useful adjunct in the assessment of the magnitude of myocardial injury in respiratory distress syndrome and asphyxia. They may also benefit centres without on-site echocardiography with some evidence showing good correlation with echo-derived markers of myocardial function. The use of troponins in the neonatal unit remains a research tool. More work is needed to explore their prognostic role and monitoring response to treatment following cardioprotective strategies. In preterm infants the effect of inotropes on myocardial function needs further study and troponin may form an integral part of this research.

Retrospective diagnosis of hypoxic myocardial injury in premature newborns

Perinatal asphyxia has a high impact on neonatal mortality, morbidity, and neurological outcome. The hypoxic effects on brain, kidney and gastrointestinal system are well recognized in newborns. While it is known that hypoxia also effects cardiac function, there are few studies of quantitative myocardial injury in premature infants who suffered hypoxia.

AIM

To investigate usefulness of cardiac troponin (cTnT) and creatinine kinase MB (CK-MB) in the diagnosis of myocardial injury due to birth hypoxia and to correlate these markers with cardiac functions as measured by echocardiogram.

METHODS

We studied 43 preterm infants: 21 with birth asphyxia and 22 controls. Echocardiographic studies and quantitative determination of cTnT and CK-MB in blood serum was performed between the 12(th) and the 24(th) h of life.

RESULTS

cTnT and CK-MB levels were higher in asphyxiated infants compared to controls (0.287 +/- 0.190 vs. 0.112 +/- 0.099 ng/mL, P < 0.001) and (18.35 +/-14.81 vs. 11.09 +/- 5.17 ng/L, P < 0.05). Among controls, we observed an elevated value of cTnT in those with respiratory distress syndrome (RDS). We found a decrease in fractional shortening (P < 0.05) and an increase in tricuspid insufficiency (P < 0.01) in asphyxiated newborns.

CONCLUSIONS

cTnT and CK-MB levels are strong indicators of myocardial injury due to perinatal hypoxia. The cTnT level was most strongly related to RDS.

Frequency of clinically unsuspected myocardial injury at a children's hospital

BACKGROUND

Ill children are at risk but rarely screened for myocardial injury. The frequency of such injury in ill children is unknown. Elevated levels of plasma cardiac troponin I (cTnI) can detect subclinical myocardial injury.

METHODS

We measured cTnI levels from 283 Children's Hospital, Boston patients (median age 2.10 years, range 0.13-22.4 years) seen in an outpatient or emergency clinic without clinically apparent cardiac disease. We took > or = 0.5 ng/mL as an indication of myocardial injury. We also measured plasma creatine kinase-MB, total creatine kinase, and myoglobin, and performed a chart review.

RESULTS

Fifteen (7.8%) of the 193 acutely ill children and 4 (4.4%) of the 90 well children had an elevated cTnI level (P = .44). Within the acutely ill group, the children with elevated cTnI were younger and had lower mean hemoglobin and hematocrit levels. Cardiac troponin I levels correlated with creatine kinase-MB (r = 0.22; P < .001) but not with creatine kinase or myoglobin. The 4 children with cTnI > 0.89 ng/mL, who also had plasma cardiac troponin T measured, showed cardiac troponin T elevations that were consistent with unstable angina levels in adults. Four children had high-level cTnI elevations (> 2 ng/mL) consistent with acute myocardial infarction levels in adults.

CONCLUSIONS

Elevated cTnI levels occur in children without clinically apparent cardiac disease and can be at adult unstable angina or acute myocardial infarction levels. Prospective studies to determine the clinical significance of these findings and their relationship to the development of cardiomyopathy are warranted.

Sequential cardiac troponin T following delivery and its relationship with myocardial performance in neonates with respiratory distress syndrome

We measured serial cardiac troponin T in babies with respiratory distress syndrome and in "healthy" controls (no cardiorespiratory support required). We investigated relationships between cardiac troponin T and myocardial performance in respiratory distress syndrome. This was a prospective observational study at a large tertiary maternity unit that recruited 104 "healthy" babies from whom individual samples were collected. A further 24 infants with respiratory distress syndrome and 14 "healthy" preterm infants had serial sampling over the first three days. We measured fractional shortening in 14 of the infants with respiratory distress syndrome. Cardiac troponin T rose from a median (interquartile range) of 10 (10-11) pg/mL on day one to 34 (22-46) pg/mL by day three, p=0.005, in "healthy" babies. In respiratory distress syndrome levels were higher, 91 (46-135) pg/mL at 6 (5-7) hours of age, p<0.001, and remained so for all three days. In babies with respiratory distress syndrome on day one cardiac troponin T correlated negatively with fractional shortening, Rho=-0.831, p<0.001, but this correlation did not persist. In "healthy" babies there is a minimal rise of cardiac troponin T by day 3. In respiratory distress syndrome there is an early and sustained elevation of cardiac troponin T, with a negative relationship with fraction shortening, suggesting significant myocardial damage of antenatal/intrapartum origin, giving rise to measurable dysfunction.

Cardiac troponin I in asphyxiated neonates

BACKGROUND

Cardiac troponins T (cTnT) and I (cTnI) are well-established markers in detecting myocardial ischemic damage in adults. Perinatal asphyxia is associated with cardiac dysfunction.

OBJECTIVES

To evaluate serum concentrations of cTnI in asphyxiated neonates and to investigate whether cTnI is correlated with the traditional markers of asphyxia.

METHODS

Blood samples were collected from 13 asphyxiated neonates (umbilical artery pH<7.18 and either a 1-min Apgar score<4 or a 5-min Apgar score<7) and 39 controls. Data on gestation, birth weight, sex, Apgar scores, mode of delivery, umbilical pH, creatinine, serum activity of aspartate and alanine aminotransferase, and QTc interval were investigated.

RESULTS

Median (range) cTnI concentrations were significantly higher in asphyxiated neonates with respect to healthy infants: 0.36 microg/l (0.05-11) versus 0.04 microg/l (0.04-0.06); p<0.01. In asphyxiated babies, no statistically significant correlations were found between concentrations of cTnI and the other markers of asphyxia.

CONCLUSIONS

In asphyxiated neonates, cTnI concentrations are higher with respect to healthy infants, suggesting the presence of myocardial damage in this group of high-risk patients. cTnI does not correlate with the traditional markers of asphyxia.

Troponin-T levels in perinatally asphyxiated infants during the first 15 days of life

AIM

To measure serial cardiac troponin-T, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase levels in asphyxiated newborn infants during the first 15 d of life.

METHODS

Troponin-T, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase (LDH) concentrations were measured prospectively in blood samples obtained from 45 asphyxiated and 15 healthy term neonates within the first 2-4 h, third, seventh and 15th days.

RESULTS

Infants with severe asphyxia had significantly higher cardiac troponin-T levels than grade I and II asphyxiated and healthy neonates within the first 2-4 h of life (0.34+/-0.21 ag/ml vs 0.07+/-0.03 ag/ml, 0.12+/-0.07 ag/ml, 0.04+/-0.02 ag/ml, respectively). Troponin-T levels remained high on days 3 and 7 in severely asphyxiated neonates. The creatinine kinase-MB levels were significantly higher in grade II and III asphyxiated neonates than grade I asphyxiated and healthy neonates within the first 2-4 h. No difference was found in creatinine kinase-MB on day 3. There was cardiac involvement in 12 (80%) newborns of group III on B mode echocardiographic images on day 1. However, no echocardigraphic pathology was found in the seventh- and 15th-day echocardiographic analysis in any groups.

CONCLUSION

Our results suggest that asphyxia-related cardiac changes were significant but reversible in severely asphyxiated neonates, and troponin T is a good determinant of the degree of injury to the heart within the first week of life. Cardiac troponin T also has a wider diagnostic frame than other diagnostic markers of myocardial damage.

Concentrations of cardiac troponin T in neonates with and without respiratory distress

AIMS

To establish a practical postnatal reference range for cardiac troponin T in neonates and to investigate concentrations in neonates with respiratory distress.

METHODS

Prospective investigation in a tertiary neonatal unit, recruiting infants with and without respiratory distress (sick and healthy infants respectively). Concentrations of cardiac troponin T were compared between sick and healthy infants, accounting for confounding variables.

RESULTS

A total of 162 neonates (113 healthy and 49 sick infants) had samples taken. The median (interquartile range) cardiac troponin T concentration in the healthy infants was 0.025 (0.01-0.062) ng/ml, and the 95th centile was 0.153 ng/ml. There were no significant relations between cardiac troponin T and various variables. The median (interquartile range) cardiac troponin T concentration in the sick infants was 0.159 (0.075-0.308) ng/ml. This was significantly higher (p < 0.0001) than in the healthy infants. In a linear regression model, the use of inotropes and oxygen requirement were significant associations independent of other basic and clinical variables in explaining the variation in cardiac troponin T concentrations.

CONCLUSIONS

Cardiac troponin T is detectable in the blood of many healthy neonates, but no relation with important basic and clinical variables was found. Sick infants have significantly higher concentrations than healthy infants. The variations in cardiac troponin T concentration were significantly associated with oxygen requirement or the use of inotropic support in a regression model. Cardiac troponin T may be a useful marker of neonatal and cardiorespiratory morbidity.

Multiorgan dysfunction in infants with post-asphyxial hypoxic-ischaemic encephalopathy

BACKGROUND

Multiorgan dysfunction (MOD) is one of four consensus based criteria for the diagnosis of intrapartum asphyxia. The theoretical concept behind MOD is the diving reflex (conservation of blood flow to vital organs at the cost of non-vital organs).

OBJECTIVES

To assess the patterns of involvement of each major organ/system and combinations of involvement in infants with post-asphyxial hypoxic-ischaemic encephalopathy (HIE), and to describe this in relation to long term outcome.

DESIGN

Retrospective cohort study.

SETTING

Regional tertiary neonatal intensive care unit at the Hospital for Sick Children, Toronto, Canada.

PATIENTS

Term neonates with post-intrapartal asphyxial HIE assessed for kidney, cardiovascular system, lung, and liver function.

OUTCOME

Death and presence or absence of severe neurodevelopmental disability.

RESULTS

Out of 130 of 144 eligible infants with outcome data, 80 (62%) had severe adverse outcome and 50 (38%) had good outcome. All infants had evidence of MOD (at least one organ dysfunction in addition to HIE). Renal, cardiovascular, pulmonary, and hepatic dysfunction was present in 58-88% of infants with good outcome and 64-86% of infants with adverse outcome.

CONCLUSIONS

MOD was present in all the infants with severe post-asphyxial HIE. However, there was no association between MOD and outcome in these infants. No relation between individual or combinations of organ involvements and long term outcomes was observed.

Volume expansion during neonatal intensive care: do we know what we are doing?

Although volume expansion is liberally used in newborn intensive care, we know little about its effects on hemodynamics or outcomes. Given appropriately to a truly hypovolemic baby, it can be life-saving, but the clinical diagnosis of hypovolemia is probably very inaccurate. We know that volume expansion has less effect on blood pressure than dopamine, and although it seems to produce immediate increases in systemic blood flow, we do not know for how long these increases are sustained. There is evidence to show that the routine use of volume expansion in preterm babies has no effect on outcome, and there is little evidence to support its routine use during resuscitation or the treatment of metabolic acidosis. Whether crystalloids or colloids are preferable is also unclear in newborns. In situations of concern related to circulatory compromise, if possible, define the hemodynamics echocardiographically. Otherwise, if in doubt, some volume should be given, although it is probably unwise to keep expanding the volume if this is not improving physiologic (blood pressure and heart rate) or echocardiographic systemic blood flow parameters.

Dopamine for prevention of morbidity and mortality in term newborn infants with suspected perinatal asphyxia

BACKGROUND

Perinatal asphyxia remains an important condition with significant mortality and long-term morbidity. Multisystem involvement including hypotension and low cardiac output is common in infants with perinatal asphyxia. Dopamine is commonly used for infants with hypotension of any etiology, with the goal of improving cardiac output and preventing its detrimental consequences.

OBJECTIVES

To determine if dopamine, compared to placebo, no treatment, volume or another inotrope reduces morbidity and mortality in term newborn infants with suspected perinatal asphyxia.

SEARCH STRATEGY

The standard search strategy of the Neonatal Review Group was used. Searches were conducted of the Oxford Database of Perinatal Trials, Cochrane Controlled Trials Register (The Cochrane Library, Issue 1, 2002), MEDLINE (1966 to March 2002), previous reviews including cross references, abstracts and conference proceedings (Perinatal Society of Australia and New Zealand 1998-2002 and Pediatric Academic Societies meetings 1998-2001).

SELECTION CRITERIA

Randomised controlled trials comparing dopamine with placebo, no treatment, other inotropic agents, or volume in infants greater than 36 weeks gestation. Perinatal asphyxia could be suspected on the basis of a cord blood pH < 7.0, cord blood base excess < -16 mEq/L or 5 minute Apgar score < 6.

DATA COLLECTION AND ANALYSIS

Standard methods of the Cochrane Neonatal Review Group with use of relative risk (RR), risk difference (RD) and weighted mean difference (WMD). The fixed effects model using RevMan 4.1 was used for meta-analysis. Data from individual studies were only eligible for inclusion if at least 75% of participants were followed up.

MAIN RESULTS

Only one study (DiSessa 1981) was eligible. This study compared low dose dopamine at 2.5 mcg/kg/min with placebo (dextrose in water). This study enrolled 14 term infants with a 5 minute Apgar <6 and a systolic BP >=50 mmHg at a mean of 10 hours age. Seven infants only were randomised to treatment with dopamine and seven to receive placebo. No significant differences between these two groups were found for mortality or long term neurodevelopmental outcome. Length of hospitalisation was not significantly different between the two groups. No study was found that examined the effect of dopamine in infants with evidence of cardiovascular compromise, nor were any studies identified in which dopamine was compared to other inotropic agents for term infants with suspected asphyxia.

REVIEWER'S CONCLUSIONS

There is currently insufficient evidence from randomised controlled trials that the use of dopamine in term infants with suspected perinatal asphyxia improves mortality or long-term neurodevelopmental outcome. The question of whether dopamine improves outcome for term infants with suspected perinatal asphyxia has not been answered. Further research is required to determine whether or not the use of dopamine improves mortality and long-term morbidity for these infants and if so, issues such as which infants, at what dose and with what co-interventions should be addressed.

ST waveform changes during repeated umbilical cord occlusions in near-term fetal sheep

OBJECTIVE

This study was undertaken to determine whether changes in the fetal ST waveform during repeated umbilical occlusion reflect the development of hypotension and acidosis.

STUDY DESIGN

Chronically instrumented, near-term fetal sheep received 1-minute total umbilical cord occlusion either every 5 minutes for 4 hours (1:5 group, n = 8), or every 2.5 minutes until blood pressure fell <20 mm Hg on 2 successive occlusions (1:2.5 group, n = 8).

RESULTS

Umbilical cord occlusion caused variable decelerations, with sustained hypertension in the 1:5 group and little change in acid-base status (pH = 7.34 +/- 0.07 after 4 hours). In contrast, the 1:2.5 group showed progressive hypotension and metabolic acidemia (pH 6.92 +/- 0.1 after the final occlusion). There was a marked increase in ST waveform height during occlusions; this increase was greater in the 1:2.5 group (P <.001), but there was overlap between the groups. ST waveform height between occlusions was significantly higher in the 1:2.5 group (P <.001) until negative and biphasic ST waveforms developed in these fetuses between occlusions in the final 30 minutes.

CONCLUSION

ST waveform elevation occurs during umbilical cord occlusions but only crudely reflects the severity of hypoxia. Interocclusion waveform height may be a better reflection of the severity of hypoxia. The appearance of biphasic and negative waveforms between occlusions may be a useful marker for severe decompensation.

Cardiac troponin T in cord blood

BACKGROUND

Perinatal asphyxia is associated with cardiac dysfunction. This may be secondary to myocardial ischaemia. Cardiac troponin T is the ideal marker for myocardial necrosis. Elevated levels in cord blood may be associated with intrauterine hypoxia and increased perinatal morbidity.

AIMS

To establish an upper limit of normal for cardiac troponin T concentration in the cord blood of infants. Relations between cardiac troponin T levels and other variables were investigated.

METHODS

Cord blood samples were collected from 242 infants and analysed. Data on gestation, birth weight, sex, Apgar scores, respiratory status, and mode of delivery were recorded.

RESULTS

A total of 242 samples were collected, and 215 samples from infants without respiratory distress were used to establish the 95th percentile of 0.050 ng/ml. The gestation of these infants ranged from 31 to 42 weeks and birth weight ranged from 1.4 to 5 kg. There were no relations between cardiac troponin T levels and the other variables in these healthy infants. Twenty seven infants developed respiratory symptoms requiring oxygen and/or ventilation. These infants had significantly higher cord cardiac troponin T levels than their healthy counterparts (median (interquartile range) 0.031 (0.010-0.084) v 0.010 (0.010-0.014) ng/ml respectively; p < 0.001).

CONCLUSIONS

Cardiac troponin T levels in the cord blood are unaffected by gestation, birth weight, sex, or mode of delivery. Infants with respiratory distress had significantly higher cord cardiac troponin T levels, suggesting that cardiac troponin T may be a useful marker for myocardial damage in neonates.

Delayed hypotension and subendocardial injury after repeated umbilical cord occlusion in near-term fetal lambs

OBJECTIVE

This study was undertaken to determine whether myocardial injury occurs after repeated intrauterine asphyxia.

STUDY DESIGN

Near-term fetal sheep with implanted instrumentation underwent either sham occlusions (n = 8) or repeated brief umbilical cord occlusions (n = 12) continued until the onset of severe (<20 mm Hg) or sustained hypotension. After 3 days of recovery, the fetal hearts were perfusion fixed.

RESULTS

Repeated umbilical cord occlusions led to a severe metabolic acidosis (pH, 6.84 +/- 0.09; lactate concentration, 14.1 +/- 1.5 mmol/L) with increasing hypotension during occlusions, which were terminated after 128 +/- 38 minutes. After the occlusions, the mean arterial pressure showed a delayed fall, which resolved after 12 hours. Ultrastructural examination showed evidence of subendocardial injury, with dilatation of sarcoplasmic reticulum, margination and clumping of nuclear chromatin, and mitochondrial swelling. The most severe morphologic changes, including electron-dense mitochondrial inclusions, were found in the fetuses with delayed recovery of the fetal heart rate after the final occlusion.

CONCLUSION

Subendocardial injury occurs after severe repeated intrauterine asphyxia in the late-gestation fetus, and this may contribute to cardiovascular compromise and the development of late decelerations.

Cardiac abnormalities in birth asphyxia

Cardiac abnormalities in birth asphyxia were first recognised in the 1970s. These include (i) transient tricuspid regurgitation which is the commonest cause of a systolic murmur in a newborn and tends to disappear without any treatment unless it is associated with transient myocardial ischemia or primary pulmonary hypertension of the newborn (ii) transient mitral regurgitation which is much less common and is often a part of transient myocardial ischemia, at times with reduced left ventricular function and, therefore, requires treatment in the form of inotropic and ventilatory support (iii) transient myocardial ischemia (TMI) of the newborn. This should be suspected in any baby with asphyxia, respiratory distress and poor pulses, especially if a murmur is audible. It is of five types (A to E) according to Rowe's classification. Type B is the most severe with respiratory distress, congestive heart failure and shock. Echocardiography helps to rule out critical left ventricular obstructive lesions like hypoplastic left heart syndrome or critical aortic stenosis. ECG is very important for diagnosis of TMI, and may show changes ranging from T wave inversion in one lead to a classical segmental infarction pattern with abnormal q waves. CPK-MB may rise and echocardiogram shows impaired left ventricular function, mitral and/or tricuspid regurgitation, and at times, wall motion abnormalities of left ventricle. Ejection fraction is often depressed and is a useful marker of severity and prognosis. Treatment includes fluid restriction, inotropic support, diuretics and ventilatory resistance if required (v) persistent pulmonary hypertension of the newborn (PPHN). Persistent hypoxia sometimes results in persistence of constricted fetal pulmonary vascular bed causing pulmonary arterial hypertension with consequent right to left shunt across patent ductus arteriosus and foramen ovale. This causes respiratory tension and right ventricular failure with systolic murmur of tricuspid, and at times, mitral regurgitation. Treatment consists of oxygen and general care for mild cases, ventilatory support, ECMO and nitric oxide for severe cases. Cardiac abnormalities in asphyxiated neonates are often underdiagnosed and require a high index of suspicion. ECG and Echo help in early recognition and hence better management of these cases.

Detection of transitory myocardial ischemia secondary to perinatal asphyxia

Transitory myocardial ischemia (TMI) is seen as a complication of severe asphyxia. Its presentation is variable, ranging from tachypnea to cardiogenic shock, and it is often masked by the predominant disease. The objective of this study was to detect TMI secondary to perinatal asphyxia in a population of asphyxiated newborns (NB) in comparison with asphyxiated NB with no evidence of TMI. From April 1996 to December 1997, 43 asphyxiated (stressed) NB were studied. Three were excluded. Patients were placed into two groups: Group A with TMI (n = 33) and Group B without TMI (n = 7). No significant differences were found in gestational age, birth weight, extrauterine age, Apgar score, or total creatine phosphokinase values between the two groups. Differences were found in CPK-MB levels and in ischemic electrocardiographic changes and blockages, especially for Group A. In this group, only 24 (72.7%) were cardiovascularly symptomatic. We conclude that TMI secondary to perinatal asphyxia is more frequent than has been reported. Thus, it would be useful in all asphyxiated NB to measure CPK-MB isoenzyme activity and patients can then be submitted to an electrocardiogram for detection in order to offer opportune treatment when required.

Selective head cooling in newborn infants after perinatal asphyxia: a safety study

AIMS

To determine the practicality and safety of head cooling with mild or minimal systemic hypothermia in term neonates with moderate to severe hypoxic-ischemic encephalopathy.

METHODS

Study group infants >/=37 weeks' gestation, who had an umbilical artery pH </=7. 09 or Apgars </=6 at 5 minutes, plus evidence of encephalopathy. Infants with major congenital abnormalities were excluded. TRAIL DESIGN: Infants were randomized to either no cooling (controls; rectal temperature = 37.0 +/- 0.2 degreesC, n = 10) or sequentially, either minimal systemic cooling (rectal temperature = 36.3 +/- 0.2 degreesC, n = 6) or mild systemic cooling (rectal temperature = 35.7 +/- 0.2 degreesC, n = 6). Head cooling was accomplished by circulating water at 10 degreesC through a coil of tubing wrapped around the head for up to 72 hours. All infants were warmed by servo-controlled overhead heaters to maintain the allocated rectal temperature. The rectal, fontanelle, and nasopharyngeal temperatures were continuously monitored.

RESULTS

From January 1996 to October 1997, 22 term infants were randomized from 2 to 5 hours after birth. All infants showed a metabolic acidosis at delivery, with similar umbilical artery pH in the control group (mean +/- standard deviation, 6.79 +/- 0.25), minimal cooling group (6.98 +/- 0.21), and mild cooling group (6.93 +/- 0.11), and depressed Apgar scores at 5 minutes in the control group (4.5 +/- 2), minimal cooling group, (4.7 +/- 2) and mild cooling group (6.0 +/- 1). In the mild-cooled infants, the nasopharyngeal temperature was 34.5 degreesC during cooling, 1.2 degreesC lower than the rectal temperature. This gradient narrowed to 0.5 degreesC after cooling was stopped. No adverse effects because of cooling were observed. No infants developed cardiac arrhythmias, hypotension, or bradycardia during cooling. Thrombocytopenia occurred in 2 out of 10 controls, 2 out of 6 minimal cooling infants, and 1 out of 6 mild cooling infants. Hypoglycemia (glucose <2.6 mM) was seen on at least one occasion in 2 out of 10 controls, 4 out of 6 minimal cooling infants, and 1 out of 6 mild cooling infants. Acute renal failure occurred in all infants. The metabolic acidosis present in all infants at the time of enrollment into the study progressively resolved despite cooling, even in the mild hypothermia group.

CONCLUSIONS

Mild selective head cooling combined with mild systemic hypothermia in term newborn infants after perinatal asphyxia is a safe and convenient method of quickly reducing cerebral temperature with an increased gradient between the surface of the scalp and core temperature. The safety of mild hypothermia with selective head cooling is in contrast with the historical evidence of adverse effects with greater depths of whole-body hypothermia. This safety study and the strong experimental evidence for improved cerebral outcome justify a multicenter trial of selective head cooling for neonatal encephalopathy in term infants.

Multiple organ involvement in perinatal asphyxia

OBJECTIVES

(1) To evaluate the frequency and spectrum of severity of multisystem dysfunction after perinatal asphyxia and (2) to analyze the relationship between the clinical and biochemical markers of perinatal asphyxia and multiorgan involvement.

STUDY DESIGN

Seventy-two consecutive term newborn infants with perinatal asphyxia were studied prospectively. Systematic neurologic, renal, pulmonary, cardiac, and gastrointestinal evaluations were performed. Involvement of each organ was classified as moderate or severe.

RESULTS

Involvement of one or more organs occurred in 82% of the infants; the central nervous system (CNS) was most frequently involved (72%). Severe CNS injury (7 infants) always occurred with involvement of other organs, although moderate CNS involvement was isolated in 14 infants. Renal involvement occurred in 42%, pulmonary in 26%, cardiac in 29%, and gastrointestinal in 29% of the infants; 15% neonates had renal failure and 19% had respiratory failure. The Apgar scores at 1 and 5 minutes were the only perinatal factors related to the number of organs involved and the severity of involvement; the Apgar score at 5 minutes had the stronger independent association. No relationship or organ dysfunction was found with the umbilical cord arterial blood pH, meconium-stained amniotic fluid, umbilical cord abnormalities, presentation, or type of delivery.

CONCLUSIONS

Our findings indicate that the Apgar score at 5 minutes, in infants who have other criteria for asphyxia, is the perinatal marker that may best identify infants at risk of organ dysfunction.

Elevation of activity of creatine phosphokinase (CK) and its isoenzymes in the newborn is associated with fetal asphyxia and risk at birth

OBJECTIVE

To investigate the relationship of creatine phosphokinase and its isoenzymes with fetal asphyxia and risk at birth.

METHODS

Thirty-five pregnant women with high-risk pregnancy were studied.

RESULTS

In 21 patients, fetal distress was diagnosed by interpretation of the fetal heart rate tracing (FHR). The remaining 14 women, having normal fetal cardiotocography, were considered as the control group. Total CK and its isoenzymes activity was measured in cord sera and 24 h after birth in peripheral blood. Abnormal FHR patterns correlate well with elevated enzyme activities. Total CK and its isoenzymes (CK-MM, CK-MB, and CK-BB) exhibited higher values in asphyxiated infants as compared to normal neonates. Electrocardiographic ischemia occurred in seven newborns who had elevated CK-MB and CK-BB levels, both at birth and within 24 h postpartum. Chromatographic study showed in normal neonates that the predominant isoenzyme was CK-MM, whereas CK-BB activity was negligible. In the newborns with abnormal FHR, CK-MB and CK-BB were increased with predominance of CK-MB.

CONCLUSIONS

Antepartum fetal distress is associated with release of CK-BB, and particularly CK-MB; therefore, these biochemical markers may indicate either brain or myocardial damage.

Newborn complications after intrapartum asphyxia with metabolic acidosis in the term fetus

OBJECTIVES

Our purpose was to determine the newborn complications after respiratory or metabolic acidosis at delivery and to demonstrate the characteristics of an asphyxial insult predictive of these complications.

STUDY DESIGN

Fifty-nine term fetuses with metabolic acidosis were matched with 59 fetuses with normal blood gas measures at delivery. Fifty-one fetuses with respiratory acidosis were also examined. A complication score expressed the magnitude of newborn complications during the 10 days after delivery.

RESULTS

Newborn complications were not increased after respiratory acidosis. Newborn complications after metabolic acidosis increase in frequency and severity with the increasing severity and duration of the metabolic acidosis. Thirty-two of the 59 newborns in the metabolic acidosis group had a high complication score. The index values predictive of high scores were the duration of the metabolic acidosis and the Apgar score at 1 minute.

CONCLUSIONS

Intrapartum fetal asphyxia with a severe metabolic acidosis accounts for complications in all newborn systems. The probability of a high complication score increases from 14% with favorable index values to 85% with unfavorable index values.

First day serum creatine kinase BB isoenzyme in high-risk infants

Serum creatine kinase BB (CK-BB) on the 1st day of life was measured by radioimmunoassay in 37 very low birth weight (VLBW) infants, 14 severely asphyxiated infants and 24 controls. The 31 survivors from the two high-risk groups were followed up for 12 months or more. VLBW non-survivors (n = 14) had significantly higher mean CK-BB levels than survivors (n = 23), (P less than 0.05). However, if only survivors were considered, CK-BB was a poor discriminator of outcome in either study group. First day serum CK-BB is not a useful predictor of neurodevelopmental outcome in surviving high-risk infants.

Transient electrocardiographic changes suggesting myocardial ischaemia in newborn infants following tocolysis with beta-sympathomimetics

Serial electrocardiograms (ECGs) were studied prospectively in 80 apparently healthy newborn infants; 30 infants exposed in utero to prolonged tocolytic therapy (21 to ritodrine and 9 to isoxsuprine) and 50 infants non-exposed in utero to drugs (control group) matched for gestational age, Apgar score, and birth weight. Duration of exposure to tocolysis was at least 30 days (30-180 days) with an oral dosage of 10 mg 3 times daily. ECGs were graded for changes suggestive of ischaemia using the arbitrary grading system described by Jedeikin et al. In all infants with ECG features of myocardial ischaemia, serum creatine-phosphokinase iso-enzyme (CK-MB) activity was measured. Six out of 21 infants to ritodrine and six out of nine infants exposed to isoxsuprine showed a degree of ECG ischaemia which persisted for several weeks. No control infant presented grade 2 or 3 ECG changes after the 5th day of life. The results of this study seem to show that prolonged tocolytic therapy with beta-sympathomimetics has side-effects on the fetal myocardium and suggest that this treatment be reserved only for selective cases and/or for short periods of time.

Persistence of atrioventricular valve regurgitation and electrocardiographic abnormalities following transient myocardial ischemia of the newborn

To determine the sequelae of transient myocardial ischemia (TMI) in term infants, we reviewed clinical and investigative data in 59 infants (37 male, 22 female) with structurally normal hearts admitted over the 2-year period of 1983-1985. Twenty-three were diagnosed prior to admission as cases of birth asphyxia (5-min Apgar score less than 6), and 36 had signs of persistent fetal circulation with electrocardiographic (ECG) changes of ischemia greater than 24 h after birth. Murmurs of atrioventricular valve regurgitation (AVVR), detected in 28 patients, were confirmed in 23 of the 24 patients investigated. The murmurs resolved over a 2-day to 6-month period (median 6 days). In three patients, AVVR, left ventricular dyskinesia, and ECG anomalies persisted for 2 months (until death), 4 months, and 48 months. Initial ECGs were abnormal in 57 patients, and (of those reviewed) 60% returned to normal over a 6-day to 7-month period (median 2 months). Residual ECG anomalies included second-degree AV block and persistent ST-T wave changes. Ten patients died from noncardiac causes. Neither the presence nor resolution of AVVR correlated significantly with the severity of birth asphyxia using the Apgar score, nor with the severity of the ischemic changes on the ECG. Although the cardiovascular sequelae of myocardial ischemia are usually transient, the data should prompt the need for careful review after the initial admission.