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Our purpose was to investigate the effects of body size on the sizes of mitral (MV) and aortic valve (AV) areas by three-dimensional (3-D) and two-dimensional (2-D) echocardiography and to create the normal values for 3-D echocardiography. A total of 168 healthy subjects aged 2-27 years were studied by digitized 3-DE, 2-DE, and Doppler echocardiography.3-D echocardiography was performed by using rotational acquisition of planes at 18 degrees intervals from a parasternal view with electrocardiogram gating and without respiratory gating. The annular levels of MV and AV were identified from short-axis cut planes and their areas were measured by planimetry. The diameters of mitral annulus, left ventricular outflow tract (LVOT), and aortic annulus were measured by 2-DE from the apical and parasternal long-axis views. Flow indices were measured by Doppler from MV inflow and the flow in LVOT and in the ascending aorta. Both MV and AV annular areas increased linearly in relation to body size. In the total study group the estimated areas for MV were 5.2 +/- 0.9 cm2/m2 by 3-DE, 3.7 +/- 0.5 cm2/m2 by 2-DE, and 2.0 +/- 0.4 cm2/m2 by continuity equation. The respective values for AV were 2.7 +/- 0.5, 2.1 +/- 0.3, and 1.8 +/- 0.4 cm2/m2. MV velocity time integral (VTI)/ascending aorta VTI increased from 0.80 (0.26) to 0.95 (0.23) with increased body surface area (BSA), whereas MV VTI/LVOT VTI was 1.2 (0.2) in all BSA groups. MV and AV annulus areas increase linearly in relation to body size. 3-DE gives greater estimates for the areas than 2-DE and Doppler equation methods. The data obtained from 168 healthy subjects may serve as a reference for clinical use in patients with various cardiac abnormalities.

Summary Background: Knowledge of normal aortic dimensions is important while evaluating children with aortic root dilatation. Objective: The purpose of the study was to create normal values for aortic dimensions with two-dimensional echocardiography and for aortic flow velocities with Doppler echocardiography in healthy children and young adults. Design and patients: One hundred and sixty-eight healthy children were studied by a single observer using digitized two-dimensional (2DE) and Doppler echocardiography. Methods: The 2DE measurements were obtained at the level of aortic annulus, sinus, sinotubular junction, before the origin of innominate artery, before and after the origin of left carotid artery, after left subclavian artery and descending aorta at the level of the diaphragm. Doppler measurements were made from ascending aorta and from descending aorta. Results: For the analysis the subjects were divided into five groups according to body surface area (BSA): 0·5–0·75 m2, 0·75–1·0 m2, 1·0–1·25 m2, 1·25–1·5 m2 and over 1·5 m2. Aortic dimensions normalized to BSA were greater in smaller children at all levels. All diameters correlated closely with age, BSA, height and weight (for each r>0·75, P

Purpose: To evaluate cardiac function by means of conventional and three-dimensional echocardiography (3DE) and measurement of natriuretic peptides in children and adolescents previously treated for childhood malignancy using individual follow-up data and matched control children as reference criteria. Patients and Methods: Thirty-nine survivors of childhood malignancy were examined in 1994 and 1998. The mean time from the diagnosis was 8.6 (3.9 to 16.8) years and between cardiac evaluations was 4.1 (3.3 to 5.1) years. Patients were divided into two groups according to therapies given (group I (n = 30): no cardiac irradiation, median cumulative anthracycline dose 210 mg/m2; group II (n = 9): irradiation in the cardiac region, median cumulative anthracycline dose 180 mg/m2). Results: Fractional shortening (FS) in 1994 was higher than in 1998 (32.5 ± 4.3 vs. 30.3% ± 3.3%, P = .009). 33% of patients in group I and 56% in group II in 1994 and 30% of patients in group I and 67% in group II in 1998 had N-terminal of the propeptide-atrial natriuretic peptide (NT-proANP) levels exceeding the 90th percentile of controls. In 1998, both groups (I and II) had lower ejection fraction (EF) measured by 3DE than their matched controls (52.9 ± 5.2 vs. 58.8% ± 3.1%, P < .001 and 50.0 ± 6.6 vs. 60.8% ± 3.2%, P = .024, respectively). Left atrial maximum volumes/body surface area were smaller in the patients than in controls. B-Type natriuretic peptide values did not differ significantly in either group. Conclusion: Left ventricular contractility decreases slowly even years after cardiotoxic cancer therapy in children. 3DE and NT-proANP measurements are effective methods to evaluate the cardiac function in these patients.

Objectives. Few data are available in the literature regarding the long-term outcome of newborns with congenital complete heart block (CHB). The aims of this retrospective study were to assess neonatal morbidity and mortality, incidences of dilated cardiomyopathy (DCM), and associated heart defects, and to establish prenatal and postnatal factors that might predict adverse outcome in children with CHB. Design and Setting. The cohort includes 91 infants with CHB diagnosed in 5 tertiary centers in Finland between 1950 and 1998. Patients. Maternal connective tissue disease was evident in 89% of the patients. At birth, the median gestational age was 37.1 weeks, and the median weight was 2969 g. Of the 91 infants, 60 (66%) were girls and 7 (8%) were twins. Results. Incidences of perinatal morbidity and mortality were 58% and 7%, respectively. The total mortality of CHB was 16%; 11 of 15 (73%) died during the first 12 months. Cumulative probability of survival at 10 years old was 82%. Pacing as a newborn was indicated in 48 of 90 cases (53%), and 36 received pacemakers at older ages. Cardiac defects not causally related to CHB were found in 38 of 90 patients (42%), of whom 22 were operated on. DCM was found in 21 (23%), of whom 13 died. During the follow-up, among 75 survivors with a median age of 9 years, 54 (72%) are free from symptoms. Poor outcome defined as clinically or pathologically evident congestive DCM was associated with intrauterine hydrops, low fetal and neonatal heart rate, low birth weight, male sex, and neonatal problems attributable to prematurity or neonatal lupus. Conclusions. Despite early pacing, CHB carries high mortality during the first 12 months of life. High incidences of DCM and associated heart defects indicate close echocardiographic monitoring of all children with CHB.

Knowledge of the contributions of transit time heterogeneity to the cardiopulmonary system is important for understanding cardiopulmonary function in patients with intracardiac shunt. We determined the heterogeneity of blood transit times occurring between the right atrium and the left ventricle. Eighty two patients with suspected left-to right shunt were investigated with first-pass 99mTc-labelled red blood cell radiocardiography at supine rest. Forty two of them had a pulmonary-to-systemic flow ratio (Qp:Qs) of less than 1.2 and they served as a control group. The remaining study subjects had a Qp:Qs ratio of 1.7 +/- 0.3 (mean +/- SD). The patients with shunt had significantly greater (p0.001) heterogeneity of transit times (49 +/- 9%) than in the controls (39 +/- 7%). Overall heterogeneity of cardiopulmonary transit times in patients with shunt showed a curvature relationship; the highest values were centred in patients with moderate to severe shunt (1.5Qp:Qs2.5). The results suggest that the increased heterogeneity of transit times mainly occurs within the pulmonary capillary bed in patients with intracardiac shunt. This is probably due to the recruitment of the open capillaries without vessel distension.

We studied the systolic blood pressure difference between the upper and the lower extremities in healthy newborn infants and the effect of the isthmic narrowing of the aorta on the possible difference. The blood pressure was measured with an oscillomerric blood pressure device from every extremity of 36 healthy infants aged 2–5 days. A Doppler echocardiography was performed for each infant to measure the aortic blood flow velocity in the ascending aorta and in the aortic arch above and below the isthmic narrowing. The mean blood pressure readings (S.D.) were the following: the right arm 76.8 (7.3)/48.1 (6.9), the left arm 77.5 (7.4)/51.6 (7.0), the right thigh 77.7 (7.1)/40.7 (5.8), the left thigh 76.8 (6.4)/39.6 (5.8), the right calf 75.5 (7.1)/46.6 (5.7) and the left calf 77.1 (8.6)/48.7 (6.7). The aortic blood flow was faster below the isthmic narrowing of the aorta (1.15 ± 0.19 m/s) than in the ascending aorta (0.93 ± 0.12 m/s) or in the aortic arch above the isthmus (0.99 ± 0.15 m/s). The calculated pressure gradient between the ascending aorta and aorta below the isthmus was 2.0 ± 1.8 mmHg and between opposite sides of the isthmus 1.5 ± 1.2 mmHg. Unlike in childhood and adolescence, the systolic blood pressure in the lower extremities of healthy newborn infants is not higher than in the upper extremities. The physiological narrowing of the aortic arch does not explain this phenomenon. If blood pressure measurements are performed on a neotrate to rule out aortic coarctation, the readings obtained must be interpreted in respect to normal values in newborns.

Although idiopathic cardiomyopathies are prognostically important and are a common indication for cardiac transplantation in all age groups, the incidence and age distribution of idiopathic cardiomyopathies in a well-defined pediatric population have been poorly characterized. A retrospective study was carried out in Finland in 1980-1991 to obtain information on the epidemiology of childhood cardiomyopathies. The medical records of all patients aged birth to 20 years with cardiomyopathy from the five university hospitals and 16 central hospitals covering the entire country were reviewed. Moreover, data on causes of death from the Finnish National Census Bureau were examined. Of the 808 potential cases screened, 118 infants, children, and adolescents, representing an average age-specific population of 1.4 million, were definitely identified as having idiopathic cardiomyopathy. The average annual occurrence of new cases was 0.65 per 100,000 population (95% confidence interval (CI) 0.53-0.79). If the 15 cases diagnosed only after death during the 12-year study period were included, the occurrence increased to 0.74 per 100,000 population per year. Fifty-six new cases of dilated cardiomyopathy and 40 new cases of hypertrophic cardiomyopathy were diagnosed during the study period, giving average annual occurrences of 0.34/100,000/year (95% CI 0.26-0.44) and 0.24/100,000/year (95% CI 0.17-0.33) for new cases of dilated and hypertrophic cardiomyopathies, respectively. At the end of 1991, the prevalence of dilated cardiomyopathy was 2.6/100,000 (95% CI 1.8-3.6) and that for hypertrophic cardiomyopathy was 2.9/100,000 (95% CI 2.0-4.0). The number of new cases of dilated cardiomyopathy per year increased over the study period, whereas the annual occurrence of hypertrophic cardiomyopathy remained relatively constant. Marked variability was seen in occurrence among the different age groups of children with dilated cardiomyopathy, suggesting that different pathophysiologic mechanisms, and possibly etiologies, may exist in different age groups.

Background/Purpose The aim of this study is to compare the experience with video-assisted thoracoscopic surgery (VATS) for patent ductus arteriosus (PDA) since 1995 with the results of conventional open surgery from the preceding 10 years. Methods The records of 60 children who underwent standard posterolateral muscle splitting thoracotomy and ligation of PDA in 1986-1995 were reviewed for the study. The data on 50 children who underwent VATS PDA ligation since 1995 were collected prospectively. Results All patients survived. Ductal bleeding requiring sutures with patches occurred once in the open surgery group. Two patients in the VATS group underwent immediate rethoracoscopy and clipping because of residual ductal flow in the postoperative echocardiography. Complications in the VATS group included 6 (12%) recurrent laryngeal nerve injuries (3 transient) and 2 chylothoraces. One patient in each group underwent open reoperation because of residual ductal flow 1 year after the initial operation. The operative time, duration of recovery room/neonatal intensive care unit care, duration of pleural drainage, and length of hospital stay were significantly shorter in the VATS group. Conclusions VATS PDA ligation gave results equal to traditional open surgery with a shorter operative time, faster recovery, and shorter hospital stay. More complications, especially recurrent laryngeal nerve injuries, occurred in the VATS group.

Objectives We investigated the presence of left ventricular hypertrophy (LVH) and features of diastolic dysfunction in genotype-confirmed children from families with hypertrophic cardiomyopathy (HCM) and healthy control children. Background In subjects with HCM-causing mutations, LVH usually does not evolve until adolescence. Diastolic dysfunction has not been systematically evaluated in children carrying HCM-causing mutations. Methods All children (aged 1.5-16.7 years) from 14 HCM families with identified disease-causing mutations (the Arg719Trp mutation in the β-myosin heavy chain gene [MYH7], the Asp175Asn mutation in the α-tropomyosin gene [TPM1], the Gln1061X mutation in the myosin-binding protein C gene [MYBPC3], and the IVS5-2A → C mutation in the MYBPC3 gene) and 53 matched control children were examined with electrocardiography and 2- and 3-dimensional echocardiography (2DE and 3DE). Natriuretic peptides were measured in children from HCM families and 67 control children. Results Of 53 children from HCM families, 27 (51%) had a disease-causing mutation (G+). G+ children had slightly thicker septum on 2DE compared with the control children ( P = .004), but only 3 (11%) of 27 G+ children exceeded the 95th percentile values of the body surface area–adjusted maximal LV thickness of healthy children (the major echocardiographic criterion for HCM). However, prolonged isovolumetric relaxation time, increased left atrial volume on 3DE, or increased levels of NT-proANP, all features suggestive of diastolic dysfunction, were found in 14 (52%) of 27 G+ children. Conclusions In children with HCM-causing mutations, signs of diastolic dysfunction are found in about half of the cases, as LVH is present only in small percentage of these children.

Aim: To evaluate the feasibility of home monitoring of oral anticoagulant treatment (OAT) in paediatric patients. Methods: A total of 19 paediatric patients received OAT and then monitored their treatment at home with CoaguChek±. Data on their International Normalized Ratio (INR) values were collected retrospectively from hospital records and from the notes kept by the families. The families of the patients were also asked to fill in a questionnaire. Results: No thrombotic or haemorrhagic complications occurred during a total amount of 44.7 follow-up years. INR: the proportion of INR values measured at home falling within the therapeutic range for the given patient varied from 33 to 86% (median 69%). The questionnaire: all respondents were satisfied with home monitoring, and 63% felt that a major advantage of home monitoring was that there was no need to perform venipuncture. While 47% of the respondents reported no disadvantages of home monitoring, 42% reported that they occasionally lacked confidence in their ability to conduct OAT correctly at home. Conclusion: Home monitoring of OAT is feasible and reasonably reliable in paediatric patients. However, it is crucial that healthcare professionals supervise the treatment and the families are provided with detailed and precise instructions on how to act in a variety of clinical situations.

Knowledge of normal aortic dimensions is important while evaluating children with aortic root dilatation.The purpose of the study was to create normal values for aortic dimensions with two-dimensional echocardiography and for aortic flow velocities with Doppler echocardiography in healthy children and young adults.One hundred and sixty-eight healthy children were studied by a single observer using digitized two-dimensional (2DE) and Doppler echocardiography.The 2DE measurements were obtained at the level of aortic annulus, sinus, sinotubular junction, before the origin of innominate artery, before and after the origin of left carotid artery, after left subclavian artery and descending aorta at the level of the diaphragm. Doppler measurements were made from ascending aorta and from descending aorta.For the analysis the subjects were divided into five groups according to body surface area (BSA): 0.5-0.75 m2, 0.75-1.0 m2, 1.0-1.25 m2, 1.25-1.5 m2 and over 1.5 m2. Aortic dimensions normalized to BSA were greater in smaller children at all levels. All diameters correlated closely with age, BSA, height and weight (for each r0.75, P0.001). The best predictor of aortic dimensions was BSA with r values over 0.84 for all estimates (P0.001). The diameters of ascending and descending aorta were similar in both genders when indexed to BSA. Flow velocities in descending aorta were greater than those measured in ascending aorta (P0.001 for all measurements). There were significant inverse correlations with heart rate and velocity time integral in ascending and descending aorta (r=-0.32 and -0.53, P0.001, respectively).The presented aortic dimensions at eight levels from the valve annulus to the descending thoracic aorta by 2DE in conjunction with Doppler measurements of ascending and descending aorta in 168 healthy subjects will serve as reference data for further studies and clinical use in patients with various cardiac abnormalities.

Objective: To establish normal values of left atrial and left ventricular volumes and function in children and young adults using three dimensional echocardiography (3DE). Methods: 169 healthy subjects aged 2 to 27 years were studied by digitised 3DE. 3DE was achieved using rotational acquisition of planes at 18° intervals from the parasternal view for the left atrium and from the transthoracic apical view for the left ventricle with ECG gating and without respiratory gating. Left atrial and left ventricular volumes could be calculated throughout the heart cycle, and the respective time–volume curves were reconstructed in each subject. Results: For the analysis the subjects were divided into five groups according to body surface area: 0.5–0.75 m 2 , 0.75–1.0 m 2 , 1.0–1.25 m 2 , 1.25–1.5 m 2 , and over 1.5 m 2 . Mean (SD) left atrial maximum volume/body surface area was 19.6 (3.5), 21.7 (3.7), 22.0 (4.7), 24.5 (4.8), and 27.4 (6.4) ml/m 2 ; left ventricular maximum volume/body surface area was 50.1 (8.8), 54.9 (10.1), 56.4 (9.9), 58.7 (11.0), and 64.4 (10.3) ml/m 2 . Left atrial active emptying increased from 19% to 35% with age ( r = 0.34, p r = −0.28, p Conclusions: Transthoracic 3DE is well suited for studying the phasic changes in left atrial and left ventricular volumes in young children as well as in adults. The data obtained from 169 healthy subjects will serve as a reference for further studies in patients with various cardiac abnormalities.

An association between low birth weight and subsequent elevated blood pressure has been demonstrated in a large number of studies, but the number of subjects born small for gestational age in these studies has been negligible. The inverse relationship between birth weight and blood pressure in children has been evaluated previously with an ambulatory blood pressure device, but only in children with normal birth weights. In this prospective case-control study from birth to the age of 12, we evaluated the ambulatory blood pressures in 50 children born at term but small for gestational age and in 50 full-term children born appropriate for gestational age. Children born small for gestational age had similar mean±SD systolic (117.5±8.5 mm Hg versus 115.3±7.4 mm Hg, P =0.221), and diastolic (69.2±5.3 mm Hg versus 67.3±4.4 mm Hg, P =0.075) 24-hour ambulatory blood pressure compared with the values of the children born appropriate for gestational age. However, 24-hour systolic blood pressure in the small-for-gestational-age children was higher (3.90 mm Hg; 95% confidence interval, 0.65 to 7.15) after adjusting for current body mass index. The difference in current body mass index was the only determinant for the difference in systolic blood pressure between the groups. Birth weight had no direct association with the blood pressure values. Impaired fetal growth may have a relationship with higher later blood pressure, but in 12-year-old children, blood pressure differences between small for gestational age and appropriate for gestational age children are much more dependent on current body size.

Aims: The purpose of the study was to assess the dynamic changes in left ventricular (LV) volume by transthoracic three-dimensional echocardiography (3DE) and to compare the results with those obtained by magnetic resonance imaging (MRI). Methods and Results: Thirty healthy children were studied by digitized 3DE and Doppler, and by MRI. Three-dimensional echocardiography of LV was performed by using rotational acquisition from the transthoracic apical view with ECG gating and without respiratory gating. The acquisition of 3DE data took 10–15 s. Threedimensional echocardiography gave similar values to MRI for EDV, ESV and LVM measurements, and the results correlated well. Peak emptying rates by 3DE and MRI were 236·6 and 169·6 ml/s and peak filling rates were 215·0 and 215·9 ml/s, respectively. Dynamic changes of LV volumes during the heart cycle were detectable with both methods. Conclusion: Digitized 3DE performed in the outpatient clinic and MRI were both useful methods for studying the physiological volume changes in left ventricle in children. These methods may be used for further study of the systolic and diastolic function of the left ventricle in various clinical conditions. (Eur J Echocardiography 2001; 2: 31–39)

OBJECTIVE—To assess the dynamic changes in left atrial volume by transthoracic three dimensional echocardiography and compare the results with those obtained by magnetic resonance imaging (MRI). DESIGN AND PATIENTS—30 healthy children (15 boys and 15 girls, aged 8 to 13 years) underwent examination by three dimensional echocardiography and MRI. METHODS—Three dimensional echocardiography of the left atrium was performed using rotational acquisition of planes at 18° intervals from the parasternal window with ECG gating and without respiratory gating. Volume estimation by MRI was performed with a slice thickness of 4-8 mm and ECG triggering during breath holding in deep inspiration. A left atrial time-volume curve was reconstructed in each child. RESULTS—Left atrial maximum and minimum volumes averaged 24.0 ml/m2 and 7.6 ml/m2 by three dimensional echocardiography, and 22.1 ml/m2 and 11.9 ml/m2 by MRI. The greater left atrial minimum volume in the latter was at least in part a result of breath holding. Dynamic changes in left atrial volume during the heart cycle were detectable by both methods. The higher temporal resolution of three dimensional echocardiography allowed a more precise evaluation of different phases. CONCLUSIONS—Three dimensional echocardiography and MRI were both useful methods for studying the physiological volume changes in the left atrium in children. These methods may be used for further study of the systolic and diastolic function of the heart. Keywords: three dimensional echocardiography; magnetic resonance imaging; left atrial volume; children

Background We studied serum N-terminal atrial natriuretic peptide (NT-ANP) in children during and after chemotherapy for cancer to determine its applicability in detecting cardiac dysfunction. Forty-three patients were receiving chemotherapy for malignancy. Forty-eight patients were off chemotherapy and survived between 0.9 and 13 (median 5) years after the diagnosis, receiving cumulative anthracycline doses between 0 and 600 (median 225) mg/m2. Procedure and Results. Cardiac evaluation of the patients included measurement of serum NT-ANP, recording of ECG, and assessment of systolic and diastolic function of the heart by echocardiography. During chemotherapy, serum NT-ANP levels were higher than in controls but varied markedly in the same individuals. Serum NT-ANP levels showed no consistent increase in the weeks following anthracycline administration. In late follow-up, serum NT-ANP levels were higher than in age-matched controls (median (range), 0.22 (0.06–0.47) vs. 0.14 (0.06–0.27) nmol/l, respectively, P < .001). The subgroup of patients with bone marrow transplantation and/or cardiac irradiation had the highest NT-ANP concentrations (0.30 (0.20–0.45) nmol/l). Conclusions. Thus, serum NT-ANP measurements seemed to represent a useful contribution in the long-term cardiac follow-up of children after cancer. This blood test can readily be included to laboratory follow-up, is reasonably inexpensive and may decrease the need for more laborious tests of cardiac function. When there is ongoing chemotherapy, NT-ANP levels are influenced by a variety of factors that invalidate its routine use during this period. Med. Pediatr. Oncol. 31:73–78, 1998. © 1998 Wiley-Liss, Inc.

Our findings are based on clinical observations and not on a designed study. However, in our University Hospital area, all children with suspected or verified HC are sent to the same pediatric cardiologist (TT). Therefore, our patients are probably representative of children with HC, at least in East Finland. Although the number of patients was small, the prevalence of VSD in children with HC was so high, that it is improbable that the association between the 2 diseases is due to chance alone. Larger studies are needed to confirm our results and to show if muscular VSDs are typical of all HC cases or of specific subgroups only. We suggest that children with HC should undergo a thorough echocardiographic examination to detect possible muscular VSDs, which are usually readily detected by modern color flow mapping techniques. Importantly, in children with a muscular VSD, the possibility of HC as an underlying pathology should be kept in mind.

Human milk and formulas with different quantities and qualities of protein were compared by measuring sequential postprandial changes in total amino acids and glycine/valine ratios in plasma of 23 healthy term neonates who had previously been breast-fed ad libitum. At the mean age of 5.5 days the infants reveived from a bottle 1/36 of their body weight of banked human milk (true protein 0.8 g/100 ml), or formula (1.5 g/100 ml of protein, whey-to-casein ratio 60: 40 (adapted) or 18: 82 (non-adapted), or 3.0 g/ml of protein, 60 : 40) after a 3.5-4 hour fast. After the feed, the sum of plasma free amino acids rose and the glycine/valine ratio fell, these changes being significant as soon as 30 min after the start of feeding and maximal at 30 min after human milk but at 60 min after the formulas. Both values returned to prefeeding levels, after human milk in 2-3 hours and after the two 1.5 g/100 ml formulas in about 4 hours, but after the 3 g/100 ml formula were still notably altered at 3.5 hours. The postprandial changes measured seemed to reflect dietary protein intake, and to be unaffected by protein quality (adapted vs. non-adapted formulas). The results show that in studies of plasma amino acids in young infants sampling times should be standardized exactly with respect ot type of previous feeding and duration of fasting.

Objectives. The aim of the study was to screen 36 unrelated patients with hypertrophic cardiomyopathy (HCM; 16 familial and 20 sporadic cases) from a genetically homogeneous area in eastern Finland for variants in the cardiac β-myosin heavy chain (β-MHC) and α-tropomyosin (α-TM) genes. Background. Mutations in the β-MHC and α-TM genes have been reported to be responsible for 30% to 40% and less than 5% of familial HCM cases, respectively. However, most genetic studies have included patients from tertiary care centers and are subject to referral bias. Methods. Exons 3-26 and 40 of the β-MHC gene and the nine exons of the α-TM gene were screened with the PCR–SSCP (polymerase chain reaction–single strand conformation polymorphism) method. Linkage analyses between familial HCM locus and two intragenic polymorphic markers (MYO I and MYO II) of the β-MHC gene were performed in 16 familial HCM kindreds. Results. A previously reported Arg719Trp (arginine converted to tryptophan in codon 719) mutation of the β-MHC gene was found in one proband and two relatives. In addition, a novel Asn696Ser (asparagine converted to serine in codon 696) substitution was found in one HCM patient. No linkage between familial HCM and the β-MHC gene was observed in 16 familial kindreds. A previously reported Asp175Asn (aspartic acid converted to asparagine in codon 175) mutation of the α-TM gene was found in four probands and 16 relatives. Mutations in the β-MHC and α-TM genes accounted for 6% and 25% familial HCM cases and 3% and 11% of all cases, respectively. Conclusions. Our results indicate that the β-MHC gene is not the predominant gene for HCM in the Finnish population, whereas HCM caused by the Asp175Asn mutation of the α-TM gene is more common than previously reported.

Prefeeding and sequential postprandial plasma amino acid concentrations were measured in 31 healthy preterm infants with gestational ages between 33 and 37 weeks at the ages of 4 to 12 days, to characterize changes after quantitatively and qualitatively different protein loads. All infants had previously been fed with human milk. The infants received a normal feed of pooled human milk (true protein 0.8 gm/dl) or of adapted or nonadapted milk formula (protein 1.5 gm/dl) from a bottle. The concentrations of all essential and several nonessential amino acids, including arginine and ornithine, rose sharply in plasma. Glycine decreased, and alanine increased slowly. Postprandial alterations in plasma total amino acids seemed to reflect the protein content of the different milks. In preterm infants, fed at three- to four-hour intervals, plasma amino acid concentrations fluctuate continuously. Thus in long-term studies and in screening, samples should be taken immediately before feeds. Postprandial plasma amino acid measurements may prove to be a useful means for testing the infant's ability to handle the protein or individual amino acid loads in various feeds.