Stroke Volume In Children Research Articles

Rightward imbalanced pulmonary perfusion predicts better exercise stroke volume in children after Fallot repair

BackgroundResidual lesions following Fallot repair are primarily pulmonary regurgitation and right ventricular outflow tract obstruction. These lesions may impact exercise tolerance, particularly because of a poor increase in left ventricular stroke volume. Pulmonary perfusion imbalance is also common, but its effect on cardiac adaptation to exercise is not known. AimTo assess the association between pulmonary perfusion asymmetry and peak indexed exercise stroke volume (pSVi) in young patients. MethodsWe retrospectively studied 82 consecutive patients with Fallot repair (mean age 15.2±3.8 years) who underwent echocardiography, four-dimensional flow magnetic resonance imaging and cardiopulmonary testing with pSVi measurement by thoracic bioimpedance. Normal pulmonary flow distribution was defined as right pulmonary artery perfusion between 43 and 61%. ResultsNormal, rightward and leftward flow distributions were found in 52 (63%), 26 (32%) and four (5%) patients, respectively. Independent predictors of pSVi were right pulmonary artery perfusion (β=0.368, 95% confidence interval [CI] 0.188 to 0.548; P=0.0003), right ventricular ejection fraction (β=0.205, 95% CI 0.026 to 0.383; P=0.049), pulmonary regurgitation fraction (β=–0.283, 95% CI –0.495 to –0.072; P=0.006) and Fallot variant with pulmonary atresia (β=–0.213, 95% CI –0.416 to –0.009; P=0.041). The pSVi prediction was similar when the categorical variable right pulmonary artery perfusion>61% was used (β=0.210, 95% CI 0.006 to 0.415; P=0.044). ConclusionIn addition to right ventricular ejection fraction, pulmonary regurgitation fraction and Fallot variant with pulmonary atresia, right pulmonary artery perfusion is a predictor of pSVi, in that rightward imbalanced pulmonary perfusion favours greater pSVi.

Functional status of the cardiovascular system in young children who had correction for congenital heart defect by the age of 1 year

Background. The topic relevance is determined by the increasing number of children with congenital heart defect (CHD) who require surgical correction at an early age. For further follow-up it is necessary to determine a functional status of the cardiovascular system (CVS), its adaptation to new conditions of hemodynamics, that is especially important in childhood during the period of morphological and functional changes in the growing organism. Aim. To assess the functional status of the CVS in children with CHD using a test with dosed exercise load (EL) to determine the need for an individual approach to physical rehabilitation.Materials and methods. The study included 80 children, who have been surgically treated for CHD by the age of 1 year. The study population included 32 (40.0%) boys and 48 (60.0%) girls; an average age of patients was 33.5 ± 4.28 months. The control group included 50 conditionally healthy children, with an average age of 35.0 ± 4.1 months; of which 23 (46%) were boys and 27 (54%) were girls. To assess the functional status of the CVS, a test with dosed EL was performed (10 squats in 20 s). Blood pressure and heart rate were measured at rest and after exercise, the double product and the quality of response index were calculated. Results. In children with CHD 2 years after surgery, resting blood pressure was lower compared with healthy children, no significant differences in heart rate between groups were found. The double product in children of the main group was close to above average value. Analysis of hemodynamic changes due to EL showed a more pronounced increase in heart rate and less pronounced increase in pulse pressure and stroke volume in children with CHD after correction, which indicates the adaptation of CVS to EL due to an increase in the rate rather than the strength of heart contractions. The quality of response index in the group of children with CHD corresponded to an irrational reaction to EL. Analysis of CVS responses to the load showed that the most prevalent type was asymptaticotonic one (when there is an increase in heart rate and almost no changes in blood pressure). In the hypertensive type (revealed in a small number of children), there is a significant increase in both heart rate and systolic and diastolic blood pressure. The time of hemodynamics backing up to the baseline parameters did not exceed 5 minutes in both groups, no child complained during the test. Conclusions. In young children who had surgical correction for septal CHD in infancy, blood pressure is characterized by low parameters, that is associated with a possible alteration in the regulation of vascular tone. The predominant type of the CVS response to EL in young children with septal CHD which was corrected in infancy is the asympathicotonic one with a normal period of restoration of hemodynamics to the baseline parameters. The test with EL allows us to individualize the program of physical rehabilitation of young children who had surgery for septal CHD in infancy, taking into account the status of CVS and the initial fitness

THE “THIRD MODE” OF BLOOD FLOW AND PARAMETERS OF CENTRAL HEMODYNAMICS IN CHILDREN WITH APPENDICULAR PERITONITIS AND DESTRUCTIVE PNEUMONIA

Introduction. In modern world literature there are no data on changes in the central hemodynamics in children with purulent-septic pathologies. Purpose: to improve diagnostics of cardiovascular disorders in children with appendicular peritonitis and destructive pneumonia using device “Cardiocode”. Material and methods. The trial with “Cardiocode” was conducted in two regional medical centers in Voronezh and Belgorod. Hemodynamic parameters were studied in healthy children (n = 60), in children with destructive pneumonia (n = 83) and in children with appendicular peritonitis (n = 98). Parameters of the central hemodynamics were studied in pre- and postoperative period until recovery. Results. It has been found out that in children with appendicular peritonitis and destructive pneumonia the heart rate exceeds normal limits by 37-58%. The stroke volume in children with appendicular peritonitis did not differ of normal values, while in children with destructive pneumonia it declines by 10-15%. Early diastole was significantly reduced on admission, by 75-85% of normal limits. Reduction of parameters was recorded in the rapid expulsion of left ventricular systole from 80% to 70% of normal limits. In children with destructive pneumonia and appendicular peritonitis, tone of the ascending part of the aorta (Vt.a) was increased as well. conclusion. Apparatus "Cardiocode" is an effective non-invasive tool for early diagnostics and for controlling treatment of hemodynamic disorders in children with appendicular peritonitis and destructive pneumonia.

Maximal stroke volume in children with repaired congenital heart disease

Aims Maximal aerobic capacity (VO2 max) has already been reported in patients with congenital heart disease (CHD). We postulate CPET parameters does not reflect cardiac performance in these patients. We compared VO2 max and maximal systemic stroke volume (SV max) in a population of children with repaired CHD. Impedance cardiography is considered accurate for stroke volume (SV) measurement during exercise testing. Materials and methods VO2 max and SV max (using impedance cardiography analysis device, Physioflox®) were measured during an upright ramp incremental cycle exercise in children with repaired congenital heart disease. Three groups were studied: G1 no residual disease n = 23, G2 with residual left heart obstruction n = 15, G3 with residual right heart obstruction and/or regurgitation n = 40. The results were also compared with comparable healthy control population (G0 n = 25). Results No significant correlation between SV (mL/m2) and VO2 max and maximal oxygen pulse (% Th) was found in all the groups. Compared to controls (G0), stroke work was lower in patients with residual lesions (P Conclusion As expected, SV max was impaired in children residual lesion after CHD repair. VO2 max and maximal oxygen pulse does not seem to reflect cardiac performance. Concomitant noninvasive SV max measurement during CPET appears to be useful to evaluate these patients during their follow-up.

CO8-54 - Peak exercise stroke volume in children and adult patients with isolated severe pulmonary regurgitation after right outflow tract surgery

CO8-54 - Peak exercise stroke volume in children and adult patients with isolated severe pulmonary regurgitation after right outflow tract surgery

Z-Value of Mitral Annular Plane Systolic Excursion Is a Useful Indicator to Predict Left Ventricular Stroke Volume in Children: Comparing Longitudinal and Radial Contractions.

The purpose of our study was to explore the pumping mechanism of the left ventricle (LV) and to examine the role of longitudinal LV contraction in LV stroke volume (LVSV) compared to a radial LV contraction. We examined 890 consecutive children without structural heart disease including 395 patients with a history of Kawasaki disease (KD). We measured the mitral annular plane systolic excursion (MAPSE), the LV end-diastolic and end-systolic dimension (LVDd), the LV radial wall displacement (LVRWD) and the LV stroke volume (LVSV). The LVSV was determined by the Doppler method. The z-values of MAPSE, LVDd, LVRWD and LVSV were calculated by the mean values and standard deviations (SDs) based upon BSA every 0.1 m(2) . We evaluated the relationship between the z-LVSV and the geometrical factors. The z-value of the MAPSE was the most powerful determinant for the z-values of the LVSV of all of the geometrical factors (β = 0.36, P < 0.0001). However, the z-values of the LVRWD did not contribute to those of the LVSV. The longitudinal LV contraction contributes more to the LVSV than the radial LV contraction, even in subjects without heart failure. Evaluation of longitudinal LV contraction using the MAPSE z-value is useful for assessing global LV function in children with various body sizes.

Increased left ventricular stroke volume in children and adults with repaired Tetralogy of Fallot (rTOF) and moderate-severe right ventricular dilatation

Increased left ventricular stroke volume in children and adults with repaired Tetralogy of Fallot (rTOF) and moderate-severe right ventricular dilatation

Quantification of mitral-valve regurgitation in a paediatric population by real-time three-dimensional echocardiography

Evaluation of mitral-regurgitation (MR) severity in infants is challenging. Real-time three-dimensional echocardiography (RT3DE) allows accurate left-ventricular volumetric measurements in adults. To validate RT3DE by measuring stroke volume in a normal paediatric population, then to use this new method to calculate regurgitant volume in paediatric patients with MR. Fifty-four patients, aged one week to 19 years, (29 without and 25 with MR) had two-dimensional echocardiography coupled with RT3DE left-ventricular volumetric acquisition. Stroke volume was calculated by the Doppler method at the aortic annulus (SV(D)). End-systolic and end-diastolic left-ventricular volumes were measured using the QLab semi-automated method; three-dimensional stroke volume (SV(3D)) was calculated as their difference. In the MR group, regurgitant volume was calculated by the PISA method (RV(PISA)) and as the difference between SV(3D) and SV(D) (RV(3D)). Regurgitant fraction was also evaluated by these methods (RF(PISA) and RF(3D)). Measurement feasibility was 88%. In the normal group, SV(3D) (27.9+/-18.1 ml) was highly correlated with SV(D) (30.7+/-19.6 ml; r=0.98; p<0.000). In the MR group, RV(PISA) (15.7+/-14.4 ml) and RV(3D) (11.0+/-10.2 ml) were well correlated (r=0.83; p<0.001). Regurgitant fractions were also well correlated (RF(PISA)=30.4+/-17.0%; RF(3D)=24.3+/-15.9%; r=0.79, p=0.006). RT3DE is a simple, rapid and reliable method for evaluating stroke volume in children and may, therefore, be useful for evaluating regurgitant volume and fraction in paediatric patients with MR.

New and old in pediatric exercise physiology.

Researchers in pediatric exercise physiology sometimes overlook previously published findings that are similar, or even identical, to their own. The intent of this review is to provide examples for the above pattern. These examples relate to the following topics: 1) is the O2 uptake plateau a necessary criterion for the establishment of maximal O2 uptake in children? 2) children's greater utilization of fat during prolonged exercise, 3) children's lower maximal blood lactate levels, 4) the higher metabolic energy cost of locomotion in children and the possible causes for this phenomenon, and 5) the lower cardiac output and stroke volume in children, at any given O2 uptake.

Acute hemodynamic effects of captopril in children with a congestive or restrictive cardiomyopathy.

The acute hemodynamic effects of captopril were evaluated at cardiac catheterization in 16 children (age, 0.3-18 years) with cardiomyopathy. Twelve children had congestive cardiomyopathy, whereas four had restrictive cardiomyopathy. Hemodynamic measurements were obtained 30 and 60 minutes after the oral administration of captopril (0.5 mg/kg). Blood pressures were measured in the aorta, pulmonary artery, right atrium, and pulmonary capillary wedge position; cardiac outputs were measured by the thermodilution technique. Hemodynamic data could not be obtained after the administration of captopril in one child with congestive cardiomyopathy because of an immediate, severe hypotensive response. In 11 of 12 children with congestive cardiomyopathy, cardiac index increased by 22%, from 2.3 to 2.8 l/min/m2 (p less than 0.05), and stroke volume increased by 22%, from 23 to 28 ml/m2 (p less than 0.05). Systemic vascular resistance decreased from 32 to 21 units.m2 (p less than 0.01), but the mean aortic pressure did not change significantly. In contrast, four children with restrictive cardiomyopathy had no change in cardiac output after captopril, but there was a trend toward significant arterial hypotension (mean aortic pressure decreased from 78 to 59 mm Hg). Thus, captopril acutely reduced systemic vascular resistance and increased both cardiac output and stroke volume in children with congestive cardiomyopathy. In children with restrictive cardiomyopathy, however, captopril did not affect cardiac output, but it did decrease aortic pressure. These data indicate that captopril may benefit children with a congestive cardiomyopathy but that captopril probably should not be used in children with restrictive disease.