Elastic properties of the ascending aorta in healthy children and adolescents. Age-related reference values for aortic wall stiffness and distensibility obtained on M-mode echocardiography.

BACKGROUND: Compliance of the aorta is important in maintaining normal cardiovascular physiology. Pathological conditions can induce changes in elastic properties, having profound effects on their prognosis. The aim of this study was to establish age-related reference values for distensibility and wall stiffness index of the ascending aorta. METHODS AND RESULTS: A total of 165 normal subjects (mean age, 11.92±4.0 years) were investigated on transthoracic echocardiography. Ascending aortic diameter was recorded in M-mode above the sinotubular junction. Blood pressure was measured simultaneously at the right arm. Aortic pulse pressure, distensibility and aortic wall stiffness index were calculated offline. Distensibility decreased significantly with age (r=-0.462, P<0.001); the regression line indicated an average decrease of 5.1 10(-3)kPa(-1) (95% confidence interval [CI]: 3.9-6.8 10(-3)kPa(-1)) per year. Significant correlations could be found between distensibility and weight, height, body surface area (BSA) and body mass index (BMI) (P<0.001). Stiffness index increased significantly with age (r=0.399, P<0.001); the regression line indicated an average increase of 0.066 (95% CI: 0.047-0.085) per year; significant correlations could be found between wall stiffness index and weight, height, BSA and BMI (P<0.001). The 2.5th and 97.5th percentiles of the distribution of distensibility and stiffness index related to age, weight, height, BSA and BMI were calculated. CONCLUSIONS: Normal values of arterial elastic properties throughout childhood and adolescence have been provided, and might serve as a reference for individuals with cardiovascular and metabolic disease.

The Munich Triathlon Heart Study: ventricular function, myocardial velocities, and two-dimensional strain in healthy children before and after endurance stress.

Intense exercise has been shown to have negative effects on systolic and diastolic ventricular function in adults. Very little is known about the normal reaction of the growing heart to endurance stress. For this study, 26 healthy children (18 males) with a mean age of 12.61 years (range, 7.92-16.42 years) took part in an age-adapted triathlon circuit. The athletes were investigated by two-dimensional (2D) echocardiographic/speckle tracking, M-mode, pulse-wave Doppler, color Doppler, and color-coded tissue Doppler at 2-4 weeks before and immediately after the race. After the competition, cardiac output increased, mediated by an increase in heart rate and not by an elevated preload, according the Frank-Starling mechanism. Two-dimensional speckle tracking showed a reduced longitudinal strain in the right and left ventricles and additionally reduced circumferential strain in the left ventricle. The late diastolic inflow velocities were increased in both ventricles, indicating reduced diastolic function due to an impairment of myocardial relaxation. Immediately after endurance exercise, systolic and diastolic functions were attenuated in children and adolescents. In contrast to adult studies, this study could show a heart rate-mediated increase in cardiac output. The sequelae of these alterations are unclear, and the growing heart especially may be more susceptible to myocardial damage caused by intense endurance stress.

Tricuspid valve surgery improves cardiac output and exercise performance in patients with Ebstein's anomaly.

BACKGROUND: Clinical, hemodynamic and functional effects of tricuspid valve surgery in patients with Ebstein's anomaly are not well understood. METHODS: Sixteen patients (median age of 27.7 years) were examined before and eight months after surgery by means of echocardiography, cardiovascular magnetic resonance (CMR) and cardiopulmonary exercise testing. RESULTS: Peak work load (1.87 to 2.0W/kg; p=0.026), maximum oxygen uptake (21 to 22 ml/kg/min; p=0.034) as well as cardiac output (2.7 to 2.9l/min/m(2); p=0.035) increased postoperatively. The reduction of tricuspid regurgitation led to a higher pulmonary stroke volume (29 to 42ml/m(2), p=0.005) and augmented the left ventricular (LV) volume (55 to 63ml/min/m(2); p=0.001) with a trend to better ejection fraction (61 to 64%; p=0.083). Right ventricular (RV) volume index (124 to 108ml/m2; p=0.034) and ejection fraction (50 to 42%; p=0.036) decreased on CMR. Echocardiographic measurements of RV function also decreased (tricuspid annular plane systolic excursion 2.3 to 1.7; p=0.002; isovolumic acceleration 0.98 to 0.65; p=0.004; and 2-d longitudinal global strain -19.3 to -16.25; p=0.006). CONCLUSION: Tricuspid valve surgery improves exercise capacity in patients with Ebstein's anomaly. The reduction of tricuspid regurgitation decreases the volume of the right ventricle and increases pulmonary antegrade flow. As a result LV volume and cardiac output increase. This hemodynamic benefit occurs despite the preload dependent reduction in RV volume and ejection fraction.

Characteristics of Doppler myocardial echocardiography in patients with tricuspid atresia after total cavopulmonary connection with preserved systolic ventricular function.

BACKGROUND: Doppler myocardial echocardiography (DME) may be an excellent additional means of assessing determinants of systolic and diastolic ventricular function in patients with tricuspid atresia (TA) after total cavopulmonary connection (TCPC). METHODS AND RESULTS: Thirty-three patients with TA and normal systolic shortening/ejection fraction (M-mode) after TCPC were studied by DME at a median age of 7.6 years (range 1.5-17 years). These results were compared to 16 age matched normal controls. Median time under a cavopulmonary shunt was 5.2 years (range 0.6-13.3 years). Isovolumic acceleration and isovolumic velocity did not differ significantly. All other systolic (S-wave acceleration-velocity and S-wave duration) and diastolic DME indices (E-deceleration-velocity, A-velocity and E/A ratio) were significantly lower in TCPC patients in comparison to normals (p<0.0001). Furthermore, isovolumic relaxation time (IRT) was significantly prolonged in the patient group (p<0.0001). Even though there was a significant correlation between the time of volume unloading and left ventricular end-diastolic diameter, exclusion of all patients with short period of volume unloading and relatively large systemic ventricles did not alter the results. CONCLUSIONS: Patients with TA after TCPC and normal shortening and ejection fraction have normal isovolumic acceleration. Load dependent DME indices of systolic and diastolic function, however, were significantly reduced. These findings suggest that the described DME indices mirror the "normal" hemodynamics after TCPC in patients with TA. It needs to be assessed, whether this is an index of adverse prognosis in long-term surveillance of these patients.