Signal-averaged electrocardiography in normal newborn infants.

Signal-averaged electrocardiograms (SAECGs) were recorded with bipolar orthogonal and standard 12-lead settings in 29 term healthy newborn infants. SAECGs performed with the two lead configurations were similar in quality and quantity. For the duration of the QRS complex (QRSD), the upper limit of normality for newborn infants can be set to 100 ms. It is similar in individual bipolar orthogonal and individual standard 12-lead recordings as well as in filtered QRSD in the vectorcardiograms (the vector magnitude, VM, and the sum of extremity leads). In individual leads of bipolar orthogonal and standard 12-lead recordings, root-mean-square voltage of the terminal 40 ms of the QRS complex (RMS40) is widely scattered and unsuitable as discriminant variable. For VM and the sum of the extremity leads, the same reference values for RMS40 and duration of low-amplitude signal can be used as applied in adults. Individual lead recordings provide complementary information in addition to vectorcardiograms. There are practical advantages using standard 12-lead compared to conventional bipolar orthogonal configurations. The widespread use of standard 12-lead ECG in routine medical practice makes its utility advantageous also in performing signal-averaged electrocardiography.

Silent and audible persistent ductus arteriosus: an angiographic study.

Persistent ductus arteriosus (PDA) murmurs become silent probably due to the direction of the jet across the ductus arteriosus when entering the pulmonary artery. Out of 15 children with silent PDA, 14 demonstrated a ductal flow not contacting and away from the anterior wall of the main pulmonary artery. In 15 children with a continuous murmur caused by a PDA, 12 exhibited a ductal flow toward and reaching the anterior wall of the MPA. There was no correlation between the presence of a murmur and the size of the arterial duct in this study.

Coil embolization of a neonatal pulmonary arteriovenous malformation.

Pulmonary arteriovenous malformation (PAVM), as a part of Osler-Weber-Rendu Syndrome, in the neonate, is a rare hereditary vascular malformation. Large intrapulmonary right-to-left shunting, causing hypoxaemia and cyanosis, can be a life-threatening condition. Repeated transcatheter coil embolization procedures proved to be a favorable strategy to improve systemic arterial oxygen saturation, with a good outcome in a newborn child. While the radiation dose was high, the use of this amount of radiation was felt to be justified and its effects considered tolerable in the treatment of this patient's serious malformation.

High-frequency components in ECG analysed in guinea-pig Langendorf preparations.

High-frequency components in ECG during global ischaemia were studied in isolated guinea-pig hearts perfused ad modum Langendorf. Electrocardiograph recordings were carried out from the epicardial surface both in normo- and low-flow perfusion. After bandpass filtering (5-500 Hz), signal-averaging, was undertaken. The high-frequency components either increased or decreased after low-flow perfusion was instituted. Root-mean-square voltage (RMS) of the depolarization signal correlated poorly with the signal amplitude, but highly with the first and second derivative, i.e. the velocity and the acceleration of the signal. It is concluded that high-frequency components are not pathological phenomena per se, but reflect the shape of the original electrocardiographic signal.

Contemporary management of children with atrial septal defects: a focus on transcatheter closure.

Atrial septal defects that result in right atrial and ventricular volume overload should be closed if diagnosed in children and adolescents. With closure of the atrial septal defect, the left-to-right shunt is eliminated e.g. the volume loading of the right heart, the excessive pulmonary blood flow and the total cardiac work load are reduced. The possibility of future arrhythmic events is lessened and paradoxical emboli across the septum eliminated. The first intracardiac surgical repair of a congenital lesion was a defect in the atrial septum nearly 50 years ago. Surgical closure remains a valuable, although viable technique. Recently percutaneous transcatheter techniques are now available. The conventional approach is via a median sternotomy incision but is associated with pain, risk of wound infection, postoperative immobilization and a permanent scar. It has been suggested that alternative approaches such as surgical repair using mini-sternotomy or lateral thoracotomy incisions yield similar results to the conventional surgical technique and are associated with fewer adverse effects. Transcatheter closure has developed over the last two decades and has evolved into a well tolerated, efficient and cost effective method with minimal discomfort for the patients. Complete closure rates are high and this approach has become a viable option for ASD management.

Holt-Oram syndrome and multiple ventricular septal defects: an association suggesting a possible genetic marker?

A family is described where the father has the many skeletal, but none of the cardiac abnormalities associated with the Holt-Oram syndrome. His two daughters have similar skeletal anomalies, but with identical cardiac lesions, as does another patient, raising the possibility of an associated genetic marker.

Successful thrombolysis of an occluded modified Blalock shunt three days after operation.

A 10-day-old boy with pulmonary atresia received a right-sided aortopulmonary polytetrafluoroethylene shunt. Three days after the operation he became cyanotic and was reintubated. Shunt occlusion was confirmed with angiography. Recombinant tissue plasminogen activator was given locally into the proximal end of the shunt. The thrombus was completely resolved after 2 days. When administration of recombinant tissue plasminogen activator was stopped, heparin infusion was started for 5 days. Shunt patency was demonstrated by angiography at 3 months postoperatively.

Hypoxic-ischaemic encephalopathy is associated with regional changes in cerebral blood flow velocity and alterations in cardiovascular function.

Doppler-derived indices of cerebral blood flow velocity (CBFV) and echocardiographic parameters of left ventricular function were measured in 18 patients with hypoxic-ischaemic encephalopathy HIE (group I) and in 28 normal controls (group II). Group-I infants had a subnormal distribution of CBFV values increasing over the first 85 h postnatally. CBFV values were constantly higher in the internal carotid than in the anterior cerebral artery. During the first 24 h postnatally, pulsatility and resistance indices of cerebral blood flow were significantly higher in group-I patients. From 30 to 85 h after birth, resistance indices were lower in group-I infants with severe HIE. Depressed left ventricular function and/or hypotension was documented in 50% of group-I patients.

Protein C activity and antigen in premature and fullterm newborn infants.

Blood was obtained from 23 premature infants (birthweights 950-2910 g at 26-35 gestational weeks), and 27 fullterm infants (birthweights 2930-4900 g at 37-42 gestational weeks). Protein C concentration and activity were analysed. In preterm infants, protein C concentrations were 2.9-24% of adult values, and those of protein C activity 6-32%, the corresponding figures for term infants being 16-60% and 8.5-60%. Protein C concentrations were below 10% of adult values in four low birthweight infants, three of whom had significant haemorrhages. Protein C activity was below 10% of adult values in three infants, all of whom suffered from major haemorrhages.

Plasma concentrations of C4b-binding protein and vitamin K-dependent protein S in term and preterm infants: low levels of protein S-C4b-binding protein complexes.

We have determined the plasma concentrations of protein S and C4BP in 25 term and 26 preterm infants by radioimmunoassay. Both the total concentration and the concentration of free protein S were quantified. The concentration of C4BP was very low in preterm infants (mean 6% of the adult level). In term infants, the level had increased to a mean of 18%. Total protein S was decreased both in preterm and term infants, 4.0 mg/l and 6.8 mg/l respectively, as compared to the mean adult concentration, 20.6 mg/l. In preterm infant plasma, free protein S was the predominant (85%) form, probably due to the very low C4BP level. In plasma from term infants, free protein S represented 68% of the total protein S, the corresponding value in adult controls being 37%. The plasma concentration of free protein S in preterm and term infants was 3.3 mg/l and 4.6 mg/l, respectively (mean adult value 7.6 mg/l). These results demonstrate that, while the total protein S concentration in preterm and term infants was very low in comparison to the adult level, the difference in the concentration of the anticoagulant, active, free form of protein S between infants and adults was less pronounced.

Changing pattern of neonatal meningitis in Sweden. A comparative study 1976 vs. 1983.

A nationwide retrospective epidemiological survey of neonatal meningitis in Sweden was performed in order to estimate possible changes in incidence, etiology and mortality. The total number of newborns with meningitis was 137 and 40 (29%) were preterm (less than 37 gestational weeks) infants and 27 of these preterm boys (20%). Meningitis from group B streptococci and Escherichia coli, the two major causative organisms in 1976, had decreased markedly in 1983. The identification rate of viral origin was more frequent during 1983 compared to 1976. The total incidence of meningitis was 8.9/10,000 livebirths in 1983 vs. 5.6/10,000 in 1976 but the rate of verified bacterial meningitis had decreased from 3.6/10,000 (1976) to 1.9/10,000 (1983). The total outcome was improved significantly since the combined mortality and handicap rates decreased from 34% in 1976 to 15% in 1983.