https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(09)60657-7.pdf

Tetralogy of Fallot

Basic fluid dynamic principles were used to derive a theoretical model of optimum cardiovascular allometry, the relationship between somatic and cardiovascular growth. The validity of the predicted models was then tested against the size of 22 cardiovascular structures measured echocardiographically in 496 normal children aged 1 day to 20 yr, including valves, pulmonary arteries, aorta and aortic branches, pulmonary veins, and left ventricular volume. Body surface area (BSA) was found to be a more important determinant of the size of each of the cardiovascular structures than age, height, or weight alone. The observed vascular and valvar dimensions were in agreement with values predicted from the theoretical models. Vascular and valve diameters related linearly to the square root of BSA, whereas valve and vascular areas related to BSA. The relationship between left ventricular volume and body size fit a complex model predicted by the nonlinear decrease of heart rate with growth. Overall, the relationship between cardiac output and body size is the fundamental driving factor in cardiovascular allometry.

https://www.physiology.org/doi/pdf/10.1152/japplphysiol.01144.2004

Theoretical and empirical derivation of cardiovascular allometric relationships in children

Background We have shown previously that transient right ventricular restriction after tetralogy of Fallot repair prolongs postoperative course. This is a prospective study of right ventricular diastolic performance in late follow-up patients. Methods and Results We studied biventricular function, using Doppler echocardiographic examination. Pulmonary arterial, tricuspid, and mitral valves and superior vena cava Doppler spectrals were obtained in 41 patients (mean age, 28.8 years), 15 to 35 years (mean, 23.6) after complete repair of tetralogy of Fallot. Patients were considered to have evidence of right ventricular restriction if antegrade diastolic flow was detected in the main pulmonary artery, coinciding with atrial systole (A wave), throughout the respiratory cycle. Exercise function was measured by graded treadmill testing with respiratory mass spectrometry. Three patients were excluded because of pulmonary outflow obstruction (Doppler gradient >40 mm Hg) or residual intracardiac shunts. Of the 38 p...

Right ventricular diastolic function 15 to 35 years after repair of tetralogy of Fallot : restrictive physiology predicts superior exercise performance

Transposition of the Great Arteries

Background—The surgical approach to aortic root aneurysm and/or dissection remains controversial. The use of valve-sparing operations, which are thought to have many advantages, is increasing. We hypothesized that the particular technique and type of surgery could influence valve motion characteristics and function. Therefore, we studied the instantaneous opening and closing characteristics of the aortic valve after the main 2 types of valve-sparing surgery. Methods and Results—In 20 patients (10 with tube replacement of the aortic root, group A; and 10 with separate replacement of the sinuses of Valsalva, group B) and 10 controls (group C), transthoracic and transesophageal studies on aortic valve dynamics were performed. Three distinct phases of aortic valve motion were identified. They were as follows: (1) a rapid opening, with a velocity of 20.9±4.2 cm/s in group C, 27.1±10.9 cm/s in group B (P=NS), and 58.3±18.4 cm/s in group A (group A versus group C, P<0.001; group A versus group B, P=0.001); (2) a...

Opening and closing characteristics of the aortic valve after different types of valve-preserving surgery

Systolic and diastolic diameters of the right and left pulmonary arteries (RPAD, LPAD), descending thoracic aorta (DTAD), right ventricular infundibulum (RVID), and pulmonary and aortic valve roots at the proximal, commissural and distal levels were estimated from angiocardiograms in 24 infants, children, and adolescents without heart disease, and correlated with body surface area (BSA), stroke volume (SV), cardiac output (CO), and ventricular volumes. The relationships between cardiovascular diameters and BSA were better expressed by a power function than by the other functions tried. We obtained different exponents for pulmonary and aortic valve annuli and the more distally measured great arteries (RPAD, LPAD, and DTAD), suggesting different growth patterns. The right ventricular infundibular shortening fraction (RVISF) was weakly correlated with BSA (r = -0.328), and the values obtained indicated constancy during normal growth. There was a direct proportional relationship between the pulmonary valve annulus diameter and the cube root of the right ventricular volume (r = 0.952), as well as between SV and cross-sections of the right pulmonary artery (RPAC; r = 0.916), left pulmonary artery (LPAC; r = 0.878) and descending thoracic aorta (r = 0.962). RPAC and LPAC were strongly correlated (r = 0.940), the RPAC being significantly larger than the LPAC.

Dimensions of the great arteries, semilunar valve roots, and right ventricular outflow tract during growth: normative angiocardiographic data.

On the basis of angiographic projections, left (n = 43) and right (n = 56) ventricular volume data were obtained in patients with tetralogy of Fallot before and after surgical repair. The postoperative patients were divided into 3 groups according to the degree of an additional volume load secondary to a residual ventricular septal defect or pulmonary insufficiency, or both. The decreased left ventricular ejection fraction (p < 0.01) in preoperative tetralogy of Fallot in the presence of a normal sized left ventricle suggests depressed global myocardial function, which is not improved after surgical repair, even if excellent results are achieved. A certain functional reserve, however, seems to be preserved, since the ejection fraction did not decrease further with increasing additional volume loads.

Similar enlargement of the right ventricle secondary to comparable degrees of pulmonary insufficiency and residual ventricular septal defect indicates similar effects of additional diastolic and systolic filling on right ventricular function in patients with tetralogy of Fallot after surgical repair. Even in patients with excellent surgical results, such as those without significant right ventricular outflow tract obstruction and additional volume load, right ventricular pump function is depressed, the ejection fraction being significantly (p < 0.01) lower than normal. The further decrease of global myocardial function with increasing volume load suggests a loss of functional reserve. Attempts to minimize right ventricular volume load after surgical repair seem advisable.

Left and right ventricular adaptation to right ventricular overload before and after surgical repair of tetralogy of Fallot

Assessment of coronary and aortic anastomoses after anatomic correction of transposition of the great arteries.

We report on the enhancement of video-angiocardiographic image-series by digital preprocessing methods including a newly developed technique of interframe subtraction recording as well as computerized image subtraction, integration, and nonlinear representation techniques. Background suppression and noise reduction obtained through these processes applied to roentgen images from animal experiments are demonstrated. Image-series handling and storage are simplified by combining a new method of digitally formatted videotape recording with conventional digital storage of selected image data in the periphery of a minicomputer system.

Paul H. Heintzen

Papers

Dimensions of the great arteries, semilunar valve roots, and right ventricular outflow tract during growth: normative angiocardiographic data.

Left and right ventricular adaptation to right ventricular overload before and after surgical repair of tetralogy of Fallot

Assessment of coronary and aortic anastomoses after anatomic correction of transposition of the great arteries.

Computerized video-image preprocessing with applications to cardio-angiographic roentgen-image series

On-line processing of the video-image for left ventricular volume determination.