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Doppler determination of cardiac output in infants and children: Comparison with simultaneous thermodilution

SummaryTen children, aged six weeks to 13 years, without intracardiac shunts or lesions that could cause turbulent flow in the ascending aorta or aortic regurgitation, underwent cardiac catheterization, including cardiac output measurements by thermodilution. Simultaneously with each of six consecutive thermodilution injections, mean and maximal blood velocities in the ascending aorta were measured by pulsed Doppler echocardiography from the suprasternal notch. Aortic root and aortic orifice diameters were measured with M-mode and cross-sectional echocardiography. One patient had to be excluded from the analysis because of inadequate Doppler recordings. The best agreement with the results of the thermodilution was observed when internal systolic aortic root diameter was combined with mean velocity (r=0.97,y=0.90x+0.28, SEE=0.31 liters/min). When cardiac output was normalized for body size, there was still a good correlation between the results of these two methods.

Arrhythmogenic right ventricular dysplasia in brother and sister: Is it related to myocarditis?

SummaryTwo cases of arrhythmogenic right ventricular dysplasia (ARVD) in siblings are reported. In the boy, 14 years old, the clinical history, ECG, echocardiography, and histopathological findings were consistent with ARVD. Premature ventricular contractions of left bundle branch block (LBBB) pattern were recorded but no ventricular tachycardia (VT). A high titer against mycoplasma and increased concentrations of immunoglobulins were found. Two years after his first admission he died suddenly. Autopsy revealed severe right ventricular (RV) myocardial damage, with fat cell infiltration and collagenous tissue. His sister presented with sustained VT of LBBB pattern 2 years later, at 12 years of age. Vaccination against rubella and signs of upper respiratory illness had preceded the symptoms. During the following 9 days ECGs and serum enzymes indicated the development of left ventricular (LV) infarction. Echocardiography revealed an enlarged RV and a normal LV. After 6 weeks both RV and LV showed akinetic areas and sacculations. We suggest that myocarditis may be a precipitating factor in ARVD, and perhaps the prerequisite for its manifestation.

Prediction of Symptomatic Patent Ductus Arteriosus in Preterm Infants Using Doppler and M‐mode Echocardiography

ABSTRACT. To investigate whether the development of symptomatic patent ductus arteriosus could be predicted, 26 preterm infants dependent on mechanical ventilation were examined daily with Doppler and M‐mode echocardiography until 3 days after birth. The presence or absence of a hemodynamically significant ductus shunt, as judged from echocardiographic criteria, was tested for predictive power in terms of sensitivity, specificity and total error rate. Out of the 26 infants 13 developed symptomatic patent ductus arteriosus at a median age of 5 days (range 2–8). These 13 infants developed echocardiographic evidence of a large shunt at a median age of 2 days (range 1–3). The sensitivity of prediction was 18, 46 and 100% at 1, 2 and 3 days after birth. The specificity was 80, 92 and 85% and the total error rate was 52, 32 and 8%. Thus, accurate prediction was possible 3 days after birth.

A case of trisomy 20

Chromosome determination in a girl who at birth had an abnormal appearance and a cats cry, and later a poor weight gain and psychomotor retardation, showed a probable trisomy of chromosome pair no. 20. The analysis was made by means of photometric examination of G‐banded chromosomes from lymphocyte cultures. The deviating chromosome was identified in fibroblast cultures as well.

Single Doppler Detection of Left to Right Shunt through the Ductus Arteriosus

ABSTRACT. Forty‐two infants and children were examined with unguided continuous and pulsed Doppler echocardiography before and/or after surgical closure of ductus arteriosus or in connection with cardiac catheterization. Presence or absence of diastolic reverse flow in the main pulmonary artery was evaluated for sensitivity and specificity to detect left to right ductus shunt. Diastolic reverse flow was detected in 15 of 16 patients with such a shunt and in 3 of 38 patients without a left to right ductus shunt. This corresponds to 94% sensitivity and 92% specifcity. It is concluded that the accuracy of a single Doppler system in diagnosing patent ductus arteriosus is comparable to the results obtained with a Doppler interfaced to M‐mode or cross‐sectional echocardiography.

Glucose metabolism and insulin secretion in children with cyanotic congenital heart disease

The aim of the study was to reveal differences in carbohydrate metabolism in children with cyanotic congenital heart diseases (CHD). Thirteen children with diseases of these kinds were investigated with regard to glucose tolerance and insulin secretion and comparisons were made with healthy controls of the same age. Investigations included an intravenous glucose tolerance test, insulin response to the glucose load in plasma and insulin secretion rate. The results reveal lower fasting glucose levels and signs of a higher insulin secretion rate in the relatively few patients in the CHD group where C‐peptide measurements were performed, but no differences in glucose tolerance. The reasons for the differences are unclear, but the chronic increases in circulating catecholamines in combination with the impaired nutritional status of these children with CHD are probably the most important factors. We conclude that these divergences in carbohydrate metabolism should be emphasized in the care of children with CHD.

Glucose metabolism and insulin secretion in infants with symptomatic ventricular septal defect.

ABSTRACT. Nineteen infants with symptomatic ventricular septal defect (VSD) were examined on, altogether, 26 occasions, when each was given an intravenous glucose tolerance test (IVGTT); concentrations of insulin‐ and C‐peptide in plasma were determined. Comparisons were made with 14 healthy infants of the same age. The VSD infants were growth retarded with lower weight/age and length/age ratios. Glucose tolerance as indicated by glucose fasting levels and response to intravenous glucose tolerance test, including glucose disappearance rate, did not differ between the two groups. In response to the glucose load, insulin in plasma was significantly less in VSD infants. In response to the IVGTT, insulin secretion rate calculated from C‐peptide levels in plasma was significantly elevated in the VSD group. We conclude that compared to healthy infants, those with symptomatic VSD have normal glucose tolerance, increased secretion rate of insulin, but decreased levels of circulating insulin in response to an intravenous glucose load. We suggest this is so because binding of insulin to peripheral receptors and/or insulin extraction in the liver somehow increases.

Plasma metabolites after a lipid load in infants with congenital heart disease

Growth retardation is common in infants with congenital heart defects. The aim of this study was to investigate whether growth retardation or type of heart defect in infants with congenital heart defects is related to disturbances in lipid metabolism. Sixteen infants with ventricular septal defects and six infants with transposition of the great arteries were given an intravenous load of lipid emulsion (Intralipid® 20mg/ml) corresponding to 0.5 g fat/kg body weight for 5 min after fasting for 8h. Blood samples were drawn immediately before the infusion and 3, 20, 60, 120 and 240 min after the infusion was completed. Plasma concentrations of triglycerides (TG), free fatty acids (FFA), ketones, lactate, pyruvate, alanine, glycerol and glucose were determined. The fatty acid patterns in the TG and FFA fractions were measured using gas chromatography. Severe growth retardation in infants with defects of these kinds was correlated to higher fasting and maximum levels of linoleic acid in plasma FFA. The maximum levels of linoleic acid in the TG fraction were positively correlated to weight SD score, and maximum glycerol levels were higher in the most growth‐retarded infants, indicating faster intravascular lipolysis. Linoleic acid in the TG fraction was still elevated at 120 and 240 min after the lipid load. Some differences between the cyanotic and VSD groups could be noted. These indicate decreased metabolic capacity to utilize released FFA in the cyanotic group. Infants with cyanotic heart defects also had higher lactate and alanine levels compared to infants with VSD. Our results support the hypothesis that lipid metabolism is disturbed in infants with congenital heart defects. □Congenital heart defect, free fatty acids, linoleic acid, lipids, lipolysis, metabolism, triglyceride

Estimation of stroke volume using Doppler echocardiography and left ventricular echocardiographic dimensions in infants and children.

ABSTRACT. To evaluate the accuracy of noninvasive determination of stroke volume in infants and children, 28 patients (age range 4 weeks to 19 years) were studied. Stroke volume was calculated according to Teichholtz from M‐mode echocardiographic tracings of left ventricular dimensions in 8 subjects. Agreement with thermodilution performed within 60 min of echocardiography was good (r=0.995, y=0.91x+1.59, SEE=1.8 ml). Since stroke volume correlated to body size we corrected for (height)3. After this correction there was still good agreement to thennodilution (r=0.88, y=1.29x‐7.13, SEE=7.1 ml/H3). M‐mode echocardiography was then used as a reference method for evaluating two ditrerent Doppler methods in the remaining 20 subjects. Continuous wave Doppler stroke distance, calculated from the mean velocity, was combined with aortic root area (Method I), and stroke dstance calculated from maximum velocity was combined with the aortic interleaflet area (Method II). Good agreement was found with Method I (r=0.95, y=l.01x‐0.14, SEE=8.1 ml) and Method II (r=0.95, y=1.04x‐1.14, SEE=8.4 ml). However, when stroke volume was normalized for (height)3, Method I was found to be superior to Method II.

Skeletal muscle energy substrates, metabolic products and enzyme activity in infants with symptomatic ventricular septal defect

Muscle biopsy studies were performed on 26 infants with symptomatic ventricular septal defect (VSD) (mean age 4.7 months) and 10 healthy infants (mean age 7.8 months). Analyses were made of muscle energy substrates, metabolic products, muscle enzyme activity, fibre types and fibre sizes. Relatively few differences were noted between the groups. The most important difference was a reduced ATP level in the VSD group. Glucose 6‐phosphate concentrations were also lower in the VSD group. These differences could indicate a low metabolic activity in skeletal muscle in infants with heart failure. Most muscle enzyme activity was comparable with the exception of lactate dehydrogenase (LD), which was lower in the VSD group. Within the VSD group, no differences were revealed in muscle substrate concentrations or muscle enzyme activity in terms of the degree of heart failure. We conclude that low energy levels are probably explained by undernourishment and/or reduced blood flow to skeletal muscle and that the lack of other discrepancies in muscle metabolism indicates a desirable relatively normal motor activity in these infants with symptomatic VSD.