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.     

Cardiac output in newborn infants with transient myocardial dysfunction

Decreased cardiac output is a common presumption in left ventricular myocardial dysfunction in neonates, but because of a lack of reliable noninvasive techniques, data on cardiac output are missing. We measured cardiac output by pulsed Doppler echocardiography in 22 newborn infants with left ventricular myocardial dysfunction diagnosed by M-mode echocardiography. Eleven neonates had severe perinatal asphyxia, seven had tachypnea, two hypoglycemia, and one septic shock; one had no symptoms. Right ventricular function was abnormal in 13 of the 22 infants. Hypotension was found in eight; cardiac output and stroke volume were low in 20. The abnormalities were more pronounced in infants with asphyxia. Six such infants were given dopamine (4 to 10 micrograms/kg/min). Within 1 hour, arterial blood pressure, cardiac output, stroke volume, and heart rate increased sharply, with normalization of the myocardial contractility; the other echocardiographic abnormalities normalized over 24 to 48 hours. Pulsed Doppler echocardiography is an advance in the detection and evaluation of therapy for left ventricular myocardial dysfunction in the neonate.     

Myocardial Dysgenesis with Persistent Sinusoids in a Neonate with Noonan's Phenotype

Structural cardiac anomalies indicative of primary myocardial maldevelopment are reported in a newborn girl with congenital heart block. The cardiac findings included disordered trabeculation of both ventricles with persistent intramyocardial sinusoids, hypoplastic papillary muscles, and dysplastic atrioventricular valves with partial downward displacement of the septal leaflet of the tricuspid valve. Dilatation of the ascending aorta and craniofacial dysmorphism including webbed neck, hypertelorism, and lowset ears raise the possibility of Noonan syndrome.     

Neonatal tricuspid insufficiency--a contribution to the differential diagnosis of the cyanotic newborn infant

A cyanotic newborn is described to illustrate and discuss the rare transient tricuspid insufficiency together with functional pulmonary atresia. Etiologically the manifold causes of perinatal asphyxia are to be taken into consideration. The clinical appearance corresponds to type A of transient myocardial dysfunction according to the classification of Rowe together with respiratory distress syndrome and heart failure. Pathogenetically the disease is based on the different histological consequences of myocardial ischaemia of the right ventricle in connection with a delayed fall of the pulmonary arterial resistance. Fetal connections lead to a pronounced right-to-left-shunt. The diagnosis is primarily established by the way of clinical and echocardiographic investigation and pulsed doppler examination. The most important differential diagnosis are in Ebstein-anomaly, obstruction and atresia of the right ventricular outflow tract. Therapy is conservative. Its aim is to improve myocardial performance and to lower right ventricular afterload. Outcome of patients with neonatal tricuspid insufficiency is uncertain and depends on the severity of myocardial ischaemia. In our patient the course has been uneventful after initial difficulties.     

Critical tricuspid insufficiency due to papillary muscle rupture. A result of prenatal hypoxic insult

Fatal tricuspid insufficiency secondary to papillary muscle rupture due to prenatal hypoxic insult occurred in a full-term newborn. The diagnosis of flail tricuspid valve should be considered when fetal distress is encountered in a newborn with persistent hypoxemia. Prenatal diagnosis of this condition combined with prompt delivery, prostaglandin E1 therapy, and possible surgical repair of the tricuspid valve may improve chances of survival.     

Functional Pulmonary Atresia in a Newborn with Normal Intracardiac Anatomy

Functional pulmonary atresia is a relatively rare clinical condition usually associated with Ebstein's malformation, tricuspid valve dysplasia, Uhl's anomaly, or transient myocardial ischemia with severe tricuspid regurgitation. The occurrence of functional pulmonary atresia associated with transient tricuspid regurgitation in a newborn with an anatomically normal heart is even more uncommon. We describe a case in which color Doppler flow mapping played an essential role in diagnosis and follow-up of this clinical condition in a newborn who had normal intracardiac anatomy.     

Is serum troponin T a useful marker of myocardial damage in newborn infants with perinatal asphyxia?

AIM: To assess the correlation of echocardiographic signs of myocardial damage to serum cardiac troponin T (cTnT) concentrations in newborn infants with perinatal asphyxia. METHODS: Electocardiograms (ECG) and echocardiograms (Echo) were obtained during the first 24 h of life from 29 asphyxiated and 30 control infants and correlated with cTnT concentrations. The echocardiographic parameters included systolic ventricular performance, preload, afterload, diastolic function, stroke volume (SV), left ventricular output (LVO), hyperechogenity of the papillary muscles and insufficiency of the atrioventricular valves. RESULTS: LVO and SV were lower but CTnT were significantly higher in asphyxiated than in control infants: 0.15 (010-0.23) vs. 0.05 (0.02-0.13), p < 0.001). Asphyxiated infants with signs of myocardial damage were associated with significantly higher cTnT than those without, 0.20 (0.11-0.28) and 0.11 (0.05-0.14 ug/L), p = 0.04. CONCLUSION: Cardiac troponin may prove to be valuable in evaluating myocardial damage in birth asphyxia. However, the degree of prematurity may complicate the assessment.     

新生儿三尖瓣腱索断裂合并重度肺动脉高压一例并文献复习

目的分析新生儿三尖瓣腱索断裂引起的三尖瓣脱垂合并重度肺动脉高压的临床特点及治疗方法。方法对河北省儿童医院新生儿科2018年11月收治的1例三尖瓣腱索断裂、三尖瓣脱垂合并重度肺动脉高压新生儿的临床资料进行回顾性分析。中文以"新生儿、三尖瓣脱垂、乳头肌或腱索断裂、肺动脉高压"为检索词在中国知网、万方数据库,英文以"(neonate OR newborn) AND (tricuspid valve prolapsed) AND (rupture OR necrosis) AND (papillary muscle OR chordae tendineae) AND (pulmonary hypertension)"为检索式在PubMed数据库中检索自建库至2020年9月报道的临床资料完整的文献,总结该病的临床特点及治疗方法。结果患儿男,9小时龄,因"生后皮肤青紫9 h"入院。患儿系足月剖宫产出生,生后10 min出现全身皮肤发绀、呼吸发憋,出生医院正压通气不能缓解,予气管插管、呼吸机辅助通气,生后9 h病情无好转转至河北省儿童医院。入院查血气分析提示动脉氧分压22.5 mmHg(1 mmHg=0.133 kPa),胸部正位X线片提示双肺透光度正常,超声心动图表现为三尖瓣前叶脱垂、三尖瓣大量反流、重度肺动脉高压、卵圆孔未闭,卵圆孔水平右向左分流。予继续呼吸机辅助呼吸,吸入一氧化氮、静脉用曲前列尼尔联合降肺动脉压治疗,患儿低氧血症逐渐缓解,好转出院。患儿在11月龄时行三尖瓣瓣叶成形术+三尖瓣瓣环成形术+卵圆孔未闭缝合术,术中证实为三尖瓣腱索断裂导致三尖瓣前叶脱垂,随访至22月龄发育状况良好。文献检索未发现中文文献,检索到英文文献12篇,加上本例共分析21例患儿资料,其中仅1例出生胎龄33周早产儿,其余20例均为足月新生儿;21例患儿中男12例。21例患儿均在生后早期出现发绀,接受气管插管机械通气,其他治疗包括吸入一氧化氮、静脉用米力农、血管活性药、利尿剂、前列环素类药物等,6例患儿接受了体外膜氧合治疗。早期报道的2例生后因心肺功能衰竭死亡,其余病例均在接受外科手术后存活,术中或尸检均发现三尖瓣脱垂、三尖瓣乳头肌或腱索断裂。结论乳头肌或腱索断裂导致三尖瓣脱垂在新生儿期罕见,患儿可发生严重低氧血症,早期识别、充分心肺支持稳定血流动力学,适时外科手术可显著降低病死率。     

Transient severe tricuspid regurgitation after transplantation of an extremely oversized donor heart in a child—Does size matter? A case report

In pediatric heart transplantation, the size of the donor organ is an important criterion for organ allocation. Oversized donor hearts are often accepted with good results, but some complications in relation to a high donor‐recipient ratio have been described. Our patient was transplanted for progressive heart failure in dilated cardiomyopathy. The donor‐to‐recipient weight ratio was 3 (donor weight 65 kg, recipient weight 22 kg). The intra‐operative echocardiography before chest closure showed excellent cardiac function, no tricuspid valve regurgitation, and a normal central venous pressure. After chest closure, central venous pressure increased substantially and echocardiography revealed a severe tricuspid insufficiency. As other reasons for right ventricular dysfunction, that is, myocardial ischemia, pulmonary hypertension, and rejection, were excluded, we assumed that the insufficiency was caused by an alteration of the right ventricular geometry. After 1 week, the valve insufficiency regressed to a minimal degree. In pediatric heart transplant patients with a high donor‐to‐recipient weight ratio, the outlined complication may occur. If other reasons for right ventricular heart failure can be ruled out, this entity is most likely caused by an acute and transient alteration of the right ventricular geometry that may disappear over time.     

A Case of an Infant with Flail Tricuspid Valve Due to Spontaneous Papillary Muscle Rupture: Was Neonatal Lupus the Culprit?

A 3-month-old infant presented in extremis with a flail tricuspid valve. The authors theorized that the genesis of her papillary muscle rupture was perinatal ischemia compounded by worsening pulmonary valvular stenosis leading to excessive fiber tension. Her underlying diagnosis of autoimmune-mediated heart block with endocardial fibroelastosis and prenatal glucocorticoid steroid treatment represents potentiating factors.     

Neonatal ECG screening for congenital heart disease in Down syndrome

We studied the value of routine neonatal electrocardiography (ECG) in the 1st 48 hours of life to diagnose congenital heart disease in 37 neonates with Down syndrome. Twenty-four infants had no clinical evidence of congenital heart disease, had normal ECGs and normal cardiac anatomy on echocardiography. Thirteen children (35.2%) had congenital heart disease. The ECG was normal in seven infants with congenital heart disease: four with atrial septal defect (ASD), two with tetralogy of Fallot (TOF) and one with ventricular septal defect (VSD). A left QRS axis deviation was found in six infants: five with complete atrioventricular septal defect (AVSD) and one with VSD and mitral valve prolapse. However, only the five infants with complete AVSD had a superior QRS axis. Although neonatal ECG detected the presence of complete AVSD in neonates with Down syndrome, it missed an equal number with other heart defects. Echocardiography remains the way reliably to diagnose or exclude congenital heart disease in these infants.     

Echocardiographic abnormalities in type IV mucopolysaccharidosis.

Cardiac involvement is well recognised in most forms of the mucopolysaccharidoses but there is poor documentation of abnormalities specific to Morquio''s syndrome (type IV mucopolysaccharidosis). Ten patients with the classic form or type A Morquio''s syndrome with a median age of 12.5 years underwent echocardiographic assessment. Abnormalities were detected in six (60%) cases with mitral valve involvement in five patients and aortic valve disease in four. One patient had severe mitral leaflet thickening to the point of mitral stenosis. Two patients had evidence for myocardial involvement by way of echocardiographic ventricular hypertrophy. The cardiac lesions were haemodynamically mild. A cardiac murmur was audible in only three of the six cases. It is concluded that there is a high prevalence of silent cardiac abnormalities in patients with Morquio''s syndrome with predominantly left sided valve involvement. Echocardiography should be part of the assessment of these patients and bacterial endocarditis prophylaxis should be advised for those with cardiac abnormalities.     

Cardiac involvement in Coffin-Lowry syndrome

Coffin-Lowry syndrome is an X-linked recessive syndrome of mental retardation, characteristic facies and skeletal anomalies. In one patient with the syndrome, we observed early recurrent episodes of congestive heart failure with intercurrent normalization and the late development of mitral insufficiency due to annular dilation and congenital abnormalities of the valve apparatus. This unusual course of cardiac involvement, the non-adaptation of the left ventricular contractility to the aggravation of the mitral insufficiency and the postoperative persistence of the ventricular dysfunction, underline the possible role of an associated primary myocardial disease. This clinical observation demonstrates clearly that a mitral valve malformation can occur in patients with the syndrome, but also the role of a dilated cardiomyopathy, which can be secondary to the mitral regurgitation, but is more likely a myocardial disorder occurring as part of the syndrome.     

Management of Asymptomatic Cardiac Murmurs in Term Neonates

Approximately 2 % of newborn infants are noted to have cardiac murmur on routine postnatal examination. Our aim was to look at current evidence and practice in the management of asymptomatic cardiac murmur in term neonates. We performed a systematic literature review and a telephone survey of all neonatal units in the United Kingdom (UK). The systematic review of the literature did not support the routine practice of four-limb blood pressure (BP), chest X-ray (CXR), and electrocardiogram (ECG) in the assessment of asymptomatic cardiac murmur in term neonates. The survey had participation from 132 (68 %) of 193 neonatal units in the UK. In an asymptomatic term neonate with cardiac murmur, 124 (94 %) units perform pulse oximetry, 100 units (76 %) measure four-limb BP, 36 units (27 %) perform a CXR, and 52 units (39 %) perform an ECG. Eight-six units (65 %) have availability of in-house echocardiography services provided mainly by paediatricians with cardiology interest in special care units and neonatologists in neonatal intensive care units. Currently there is wide variation in practice in the management of asymptomatic cardiac murmur in term neonates. There is no evidence to support the routine use of four-limb BP, CXR, and ECG in the assessment of asymptomatic cardiac murmur in term neonates. Based on the evidence available, both structured clinical examination (including determining presence and quality of bilateral femoral pulses) and universal use of pulse oximetry are most important in identifying CHD in asymptomatic term neonates with cardiac murmur before discharge home.     

Diagnostic value of chest radiography and electrocardiography in the evaluation of asymptomatic children with a cardiac murmur

We investigated the diagnostic value of the chest radiograph and ECG in the evaluation of whether asymptomatic children with a cardiac murmur had a heart disease as defined by echocardiography. One hundred children aged 1 month to 15 years (median 30.1 months) were included. After physical examination, a tentative diagnosis was made: 53 children had no heart disease, 24 had a probable heart disease and 23 children were thought to have heart disease on the basis of clinical assessment alone. After information from chest radiography and electrocardiography was obtained, the diagnoses were re-evaluated. This resulted in a change of the tentative diagnosis in three children. However, the diagnosis in relation to the definite diagnosis by colour Doppler echocardiography was not changed to the correct diagnosis in any of these cases. In 24 cases, radiography suggested the presence of heart disease; however, only 10 of these had heart abnormalities on the colour Doppler echocardiogram (CDE). Three children had an abnormal ECG; all of these had abnormalities on the CDE, but they were already diagnosed as having heart disease by physical examination. We conclude that chest radiography and electrocardiography is of no help in the discrimination between heart disease and no heart disease in asymptomatic children referred for a cardiac murmur.     

Prevalence of T-lymphocyte abnormalities in infants with congenital heart disease

Thirty-two infants younger than 6 months with catheterization-proved congenital heart disease were prospectively examined for T-lymphocyte immunodeficiency (compared with adult and normal newborn controls). Cardiac lesions were separated into two groups: (1) "high-risk" lesions previously associated with T-cell abnormalities in DiGeorge's syndrome, and (2) the remaining "low-risk" lesions. Cardiac patients as a whole did not have significant abnormalities in T-cell rosette (TCR) percentages (mean +/- SE, 50.0% +/- 22%) or response to phytohemagglutinin (PHA) (72,243 +/- 38,388 counts per minute). However, a greater percentage of patients with high-risk cardiac lesions had abnormal TCR and PHA results than either the control or low-risk group, due to the inclusion of three infants with DiGeorge's syndrome. These findings suggest that newborn infants without evidence of DiGeorge's syndrome have normal T-lymphocyte function. Infants with high-risk cardiac lesions deserve a careful immunologic evaluation to avoid significant morbidity and mortality.     

CIRCULATORY ADAPTATION IN NEWBORN INFANTS OF STRICTLY CONTROLLED DIABETIC MOTHERS

ABSTRACT. Possible relations between neonatal circulatory function and maternal diabetic control were investigated in 22 infants of strictly controlled diabetic mothers during the first 2 days after birth. Eleven infants were delivered vaginally (V) and 11 infants by elective cesarean section (S). Maternal diabetes was more severe in the latter group. Half of the infants had one or more episodes of neonatal morbidity although none presented symptomatic hypoglycemia. Plasma glucose FFA and C-peptide were measured at birth and 3-6 hours later together with skinfold thickness; heart size was determined by X-ray at 24-28 hours; stroke volume and cardiac output were repeatedly determined by transthoracic impedance and ECG. C-peptide at birth was higher in group S than in V. C-peptide in both groups were neither related to glucose or FFA nor to birthweight or skinfold thickness. Infants with neonatal complications including cardiomegaly had the highest C-peptide values. Skinfold was positively correlated to maternal pregnancy glucose level, birthweight percentile and infant heart volume. Mean values for stroke volume and cardiac output were similar in both groups and not different from normal controls when related to body weight. Heart volume and stroke volume were significantly related. ECG abnormalities were seen in 6 infants who showed cardiomegaly on X-ray. We suggest that the present finding of an association between elevated C-peptide concentration at birth and the occurrence of neonatal complications including cardiomegaly and ECG abnormalities could be the consequence of functional hyperinsulinism and that the cardiomegaly is of adaptive type.     

Respiratory distress in a special care baby unit in Nigeria

Although respiratory distress is common among African newborn infants in special care, respiratory distress syndrome, which is the commonest cause of respiratory distress in other races, has been reported as uncommon among African infants. A prospective study of 312 consecutive newborn Nigerian infants admitted to a special care unit revealed 103 (33%) with respiratory distress. In 100 cases studied there was transient tachypnoea of the newborn ( TTN ) in 40% while specific diseases such as pneumonia and septicaemia, severe aspiration syndromes and respiratory distress syndrome (RDS) accounted for 25%, 19% and 12%, respectively. TTN and RDS occurred mostly among preterm infants with moderate perinatal asphyxia while severe aspiration syndrome was found among term infants with severe birth asphyxia. The study suggests that prevention and/or improved management of perinatal asphyxia and infections should reduce the incidence and mortality associated with neonatal respiratory distress.     

Echocardiogram in mitral-aortic atresia: False identification of the ventricular septum and left ventricle

Summary M-mode echocardiograms were correlated with cardiac anatomy in six newborn infants who had autopsy-confirmed mitral-aortic atresia. Echoes from the mitral valve or the aortic valve were not identified. An echo resembling that from the ventricular septum was recorded posterior to the tricuspid valve in all six infants. This echo was separated from the posterior ventricular wall echo by a space that varied in width from 3 to 8 mm. In two infants, the echo was continuous with that from the posterior aspect of the aortic root area and in all six infants displayed an anterior systolic motion pattern. Autopsy demonstrated that in every case the left ventricle was minute and was located superiorly in the wall of the right ventricle; in life, the transducer beam would not have traversed the left ventricle. The right ventricle was enlarged in every case and had prominent trabeculations of the septal band that created large anatomic spaces within the right ventricle. This study suggests that echoes previously thought to represent the left ventricle and ventricular septum in infants with mitral-aortic atresia do not represent these structures and are possibly created by the unusual right ventricular anatomy. Recognition of this false-positive finding may be useful in the interpretation of echocardiograms of other lesions in which there are abnormalities of the aortic or mitral valve, especially if there is a dominant right ventricle. Supported by grant HL-07605 from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland     

Cardiac outcomes of hydrops as a result of twin–twin transfusion syndrome treated with laser surgery

Aim:   To determine cardiac outcomes of foetal hydrops as a result of twin–twin transfusion syndrome treated with laser surgery.
Methods:   Hydrops identified in 16 recipient foetuses with twin–twin transfusion syndrome was treated with laser ablation surgery to anastomotic vessels. Prior to laser surgery, the foetuses were assessed by echocardiography for cardiac abnormalities and ventricular and valvular dysfunction. After delivery, echocardiography was performed on 15 of the 16 newborn infants.
Results:   Foetal echocardiography indicated impaired biventricular function in the 16 hydropic foetuses. Five foetuses had little or no forward flow through the pulmonary valve, while four had pulmonary regurgitation. Following laser surgery performed at a mean of 22.9 weeks gestation, hydrops resolved in all cases. Delivery occurred at a mean of 33.6 weeks gestation. Post-natal echocardiography revealed cardiac abnormalities in five neonates, of whom three had right ventricular outflow tract obstruction. One preterm infant with severe pulmonary stenosis died with intractable cardiac failure.
Conclusion:   The majority of hydropic infants with twin–win transfusion syndrome have normal cardiac outcomes following intrauterine laser surgery. As up to one-third may have cardiac abnormalities, cardiological monitoring is recommended during the first year of life.