Otto Daniëls

Assessment of myocardial velocities in healthy children using tissue Doppler imaging

The objective was to determine the normal range of tissue velocities in paediatric hearts as measured by tissue Doppler imaging. A prospective study was carried out involving 160 healthy children (mean age 10.8 y, range 4.0-17.9 y). Using tissue Doppler imaging (TDI) from parasternal long axis and apical views, peak velocities and peak myocardial velocity differences across the right ventricular anterior wall, interventricular septum and left ventricular posterior wall were assessed during systole, early and late diastole. The existence of transmyocardial velocity differences between the left and right side of the interventricular septum, as well as between the endocardium and epicardium of the left ventricular posterior wall was observed throughout the heart cycle. With range-gated TDI from apical four-chamber view, peak velocities were measured within the basal, mid and apical parts of the interventricular septum, and the left and right free ventricular walls. The highest peak systolic, early and late diastolic velocities were measured within the basal parts of all myocardial walls. The ranges of the calculated velocity ratios (early-to-late diastolic velocity and early diastolic-to-systolic velocity) for the various wall parts appeared to be overlapping. The correlations of peak myocardial tissue velocities and their ratios with age and weight were weak and practically irrelevant. These normal values of peak myocardial velocities, transmyocardial velocity differences and the ratios of peak wall velocities can be used as reference values in future investigations of ventricular dysfunction in this age group.

TISSUE DOPPLER IMAGING IN DETECTION OF MYOCARDIAL DYSFUNCTION IN SURVIVORS OF CHILDHOOD CANCER TREATED WITH ANTHRACYCLINES

The applicability of tissue Doppler imaging (TDI) was investigated for estimating cardiac function in long-term survivors of childhood cancer treated with anthracyclines. A total of 63 children (age range 7.8-17.3 y) underwent standard echo Doppler cardiographic studies of blood flow velocities, left ventricular dimensions and fractional shortening, followed by measurements of peak myocardial velocities and direction using the noninvasive tissue Doppler imaging (TDI) technique. All 63 were late survivors (median 7.1 y, range 3.5-13.5 y after end of therapy) who had received mean (+/- SD) cumulative dose of 242 (+/- 141) mg/m(2) of anthracyclines. The control group consisted of 160 healthy subjects (age range 4 to 17.9 y). Standard echo-Doppler anatomical parameters that were found significantly (p < 0.01) different for the study group are: RV wall thickness (decreased); LV diameter (increased); and LV fractional shortening (decreased). Studied hemodynamic parameters were not found to be different between the two groups. Quantitative TDI parameters: peak late diastolic myocardial velocities, as well as transmyocardial systolic and diastolic velocity differences, were significantly lower in late survivors than in the healthy pediatric population (p < 0.01). Qualitative local functional impairment of the movement of the left ventricular walls was detected in 20% of the patients. TDI might become a useful noninvasive method for detecting subclinical myocardial damage in apparently healthy children who received moderate doses of anthracyclines for treatment of childhood malignancy. Prospective studies with TDI for the detection of regional myocardial abnormalities are recommended.

Doppler flow characteristics in the main pulmonary artery and the\(\overline {LA} /Ao\) ratio before and after ductal closure in healthy newborns/Ao ratio before and after ductal closure in healthy newborns

SummaryEcho-Doppler (ED) techniques were used to estimate the time of closure of the ductus arteriosus in 30 normal neonates. We found that after birth there was a left-to-right (L-R) shunt through the ductus, which disappeared within 14 hours in 50% of the neonates investigated. Furthermore, patency of the ductus was not associated with a murmur. After closure of the ductus there was a significant diminution of the echocardiographically determined left atrium/aortic (

Left ventricular myocardial function in congenital valvar aortic stenosis assessed by ultrasound tissue-velocity and strain-rate techniques

\overline {LA} /Ao

Cerebral blood flow fluctuation in low-risk preterm newborns

) ratio, which was used as a measure of the L-R shunt.

Difficulties generated by the small, persistently patent, arterial duct

Abstract Background: Evidence is accumulating that periconceptional folic acid supplementation may prevent congenital heart defects (CHD). The methionine synthase reductase (MTRR) enzyme restores methionine synthase (MTR) enzyme activity and therefore plays an essential role in the folate- and vitamin B12-dependent remethylation of homocysteine to methionine. We studied the influence of the MTRR 66A>G polymorphism on CHD risk. In addition, possible interaction between this variant and plasma methylmalonic acid (MMA) concentrations, as an indicator of intracellular vitamin B12 status, was investigated. Methods: Case-control and case-parental studies were conducted to explore this association. In total, 169 CHD patients and 213 child controls, and 159 mothers with a CHD-affected child and 245 female controls were included. Results: The maternal MTRR 66AG and GG vs. AA genotypes revealed an odds ratio (OR) of 1.3 (95% CI 0.72–2.20) and 1.3 (0.71–2.37), respectively. Family-based transmission disequilibrium analysis did not reveal a significant association of the foetal 66G allele with the development of a heart defect in children (χ2=2.94, p=0.086). Maternal 66GG genotype in combination with high MMA concentration (above the 80th percentile) was associated with a three-fold (OR 3.3, 95% CI 0.86–12.50) increased risk for all types of CHD in offspring. Conclusions: These data indicate that maternal MTRR 66A>G polymorphism is not a risk factor for CHD. Maternal MTRR 66GG genotype with compromised vitamin B12 status may possibly result in increased CHD risk. In addition to folate, vitamin B12 supplementation may contribute to the prevention of CHD. Clin Chem Lab Med 2006;44:1317–23.

Cerebral blood flow fluctuation in neonatal respiratory distress and periventricular haemorrhage

A pilot study was performed to reveal the potentials of new echo Doppler techniques for the detection of myocardial changes due to congenital valvar aortic stenosis. A total of 24 patients, (age range 0.1 to 17 years), with various degrees of aortic stenosis, and 24 age- and gender-matched, healthy children were enrolled in this study. Conventional echo Doppler, tissue velocity imaging (TVI) and strain-rate imaging (StRI) measurements were carried out using the apical four-chamber view and transthoracic long-axis view. All patients had normal fractional shortening of the left ventricle (> 28%). Although the sum of septal and ventricular wall thicknesses was significantly increased in the patients (p < 0.001), only 6 of the 24 patients showed left ventricular hypertrophy. In tissue velocity mode, systolic and early diastolic wall velocity acceleration was significantly reduced in both views. Peak systolic and early diastolic wall velocities, as well as strain rate values, in the four-chamber view were significantly reduced in the patient group. The decrease was highest for the strain-rate values in all cases. In conclusion, strain rate values at different moments within the heart cycle might become important parameters in the assessment of myocardial impairment. Further studies are indicated to assess the correlation of these parameters with the severity of stenosis, left ventricular hypertrophy and irreversible myocardial function changes.

Open-heart surgery at school age does not affect neurocognitive functioning

This study investigated improvement of diagnosing myocardial damage caused by anthracyclines using tissue Doppler imaging (TDI). The optimal set of conventional echocardiographic and/or TDI parameters, needed for the discrimination of survivors from healthy controls, was retrospectively assessed. A total of 60 patients and 99 controls, age range 8.5 to 17.6 years, were studied. The survivors received 50 to 400 mg/m(2) cumulative dose of anthracyclines, with a mean follow-up of 7.3 (+/-2.3) years. The parameters used in the discriminant score (S-score) were selected from a large set of 51 echocardiographic parameters, using logistic regression analysis (stepwise selection). The correct classification probability (C-index) and the generalized distance (d) between the distributions of S-scores were used to measure the overall discriminative performance of each echocardiographic technique separately and in combination. The overall discriminative performance of the conventional echo-Doppler parameters (C = 77.3%, d = 1.04) was lower than that of the TDI (C = 84.2%, d = 1.37); the highest C-index was obtained using both techniques (C = 89.2%, d = 1.66). The set of parameters includes: LV fractional shortening and MV early diastolic flow velocity, two long-axis and five apical 4-CV TDI wall velocities (systolic and diastolic). In the patient group, the S-score was positively associated with cumulative dose of anthracyclines (p = 0.05) and duration of treatment (p = 0.01). The diagnostic index S-score, based on a limited number of variables from both techniques simultaneously, could retrospectively discriminate asymptomatic children with anthracycline-induced cardiomyopathy from healthy controls. The potentials of the S-score for serial and prospective studies are further investigated.