Oxygen uptake transient kinetics during constant-load exercise in children after operations of ventricular septal defect, tetralogy of Fallot, transposition of the great arteries, or tricuspid valve atresia.

Cardiovascular function accounts for endurance performance and, by a rapid increase in oxygen supply at the onset of exercise, contributes to short-lasting intensive exertion prevailing in many kinds of sports activities. This study determined the time for oxygen uptake (VO2) to reach one half of its asymptotic level above rest, and the respective oxygen deficit following the onset of a constant-load exercise corresponding to 80% to 90% of the maximal oxygen uptake (VO2max) in 35 children after surgical closure of a ventricular septal defect, after corrective surgery for tetralogy of Fallot, or after the Senning, Mustard, or Fontan procedures. In addition, VO2max and maximal blood lactate were determined. The half-time of VO2 response and oxygen deficit was lowest in patients after closure of a ventricular septal defect, whereas children had the most unfavorable VO2 transient kinetics after Fontan operation or with a transannular patch after correction of tetralogy of Fallot. A negative correlation was evaluated between half-time of VO2 response and VO2max, whereas maximal blood lactate varied independently of VO2max. It is concluded that many children with decreased VO2max after cardiac surgery also have unfavorable VO2 transient kinetics. In addition to being less qualified for endurance performance, they are also less prepared for short-lasting intensive energy expenditure. Therefore, the primary aim of training in these children is to improve the economy of motion of the respective tasks.

Endothelin (ET-1) is involved in the contrast media induced nephrotoxicity in children with congenital heart disease.

In 77 children with congenital heart disease urinary endothelin-1 (ET-1), an indicator of intrarenal endothelin release, was compared to urinary excretion of total protein, albumin, immunoglobuline G (IgG), alpha 1-microglobuline (alpha 1-MG), N-acetyl-beta-D-glucosaminidase (NAG) and villin. Urine samples were collected the day before and immediately after cardiac angiography with high (Conray 70; n = 56; CON) or low osmolality contrast media (Solutrast 300; n = 21; SOL) to assess the relationship between urinary endothelin and glomerular and tubular nephrotoxicity of contrast media. The children were further subdivided according to age: less than 1 year-CON 1 (n = 20); SOL 1 (n = 12) and 1-18 years CON 2 (n = 36); SOL 2 (n = 9). Results (median): 1. There are no significant changes in total protein-, albumin- and IgG-excretion as parameters of glomerular toxicity. 2. Tubular toxicity of contrast media is shown by significant increase of alpha 1-MG-(10.0 to 23.2 mg/g Crea; p < 0.001), NAG-(5.9 to 9.6 mg/g Crea; p < 0.001) and Villin-excretion (1.0 to 2.0 STS, p < 0.001) in all children. 3. Endothelin excretion (101.0 to 163.0 ng/g Crea, p < 0.001) and concentration (42.5 to 56.0 pg/ml; p < 0.001) were elevated after angiography in all children. 4. The changes in endothelin excretion are correlated to the changes in alpha 1-MG (r = 0.65; p < 0.001) and NAG (r = 0.43, p < 0.001) in all children.(ABSTRACT TRUNCATED AT 250 WORDS)

Velocity of oxygen uptake response at the onset of exercise: A comparison between children after cardiac surgery and healthy boys.

A comparison was carried out concerning maximal oxygen uptake, oxygen uptake adjustment at the onset of high-intensity exercise, and maximal blood lactate between 10 healthy prepubertal boys and 35 children after repair of cardiac malformations or after Fontan operation. Mean maximal oxygen uptake (VO2) was moderately reduced in children after repair of tetralogy of Fallot or after Mustard or Senning operations and severely reduced after Fontan operations. Conversely, mean half-time of VO2 response was moderately prolonged in children after repair of tetralogy of Fallot or after Senning and Mustard operations and considerably prolonged after Fontan operations. According to our results unfavorable kinetics of VO2 response to physical exercise are present in addition to reduced aerobic power in many of the operated children. Besides being less qualified for endurance performance, these children are also less prepared for short, high-intensity exercise.

[Fetal complete heart block with myocarditis and maternal SS-A-/AA-B/antibodies]. / Fetaler kompletter Herzblock und Myokarditis bei mütterlichen SS-A-/SS-B-Antikörpern.

We report on a newborn with fetal acquired heart block (CHB). CHB is a rare, irreversible defect, commonly occurring in conjunction with myocarditis in the neonatal lupus syndrome. Development of CHB is strongly associated with maternal anti-SS-A(Ro)/SS-B(La) antibodies. Intrauterine therapy of CHB is not possible. Concomitant myocarditis, however, can be treated effectively with dexamethasone. Mothers with an elevated risk of fetal CHB can be identified by their history (underlying systemic connective tissue disease, previous pregnancies with CHB), an immunogenetic predisposition (HLA-DR3) and analysis of the SS-A/SS-B antibody pattern. In these pregnancies prevention of CHB with plasmapheresis plus dexamethasone during pregnancy may be possible.