The role of stress echocardiography in children

Exercise and pharmacological stress echocardiography are well-accepted techniques of evaluating coronary artery disease in adults. In children, however, experience with stress echocardiography is limited and continues to evolve. The objective of this focused review was to describe the experience with exercise and dobutamine stress echocardiography in the pediatric population, with an emphasis on technique, current indications, and future directions. Experience is reported in children with prior Kawasaki disease or heart transplant recipients, as well as patients with congenital coronary abnormalities. In addition, stress echocardiography has been used in patients who have undergone coronary artery bypass graft surgery to evaluate short- and long-term graft patterning. Stress echocardiography appears to be a feasible, safe, and useful modality for the noninvasive assessment of flow-limiting stenosis in the pediatric population and can be used serially in the routine follow-up and risk stratification in children at risk for coronary events.     

平板运动试验变时性不全对冠心病诊断价值分析

目的对照平板运动试验与冠状动脉造影结果，探讨平板运动试验心脏变时性不全对冠心病诊断的价值。方法在行平板运动试验检查者中选择资料完整的行平板运动试验与冠状动脉造影的患者进行结果对照，观察运动引起心脏变时性不全与冠状动脉造影之间的联系，并与ST段压低诊断冠心病相比较。结果846例平板运动试验中有6例心脏变时性不全，并且冠状动脉造影均阳性。结论在平板运动试验中心脏变时性不全可以准确诊断冠心病，并且较ST段压低更加敏感。     

Assessment of cardiac function by M-mode echocardiography in selenium-deficient phenylketonuric children

Selenium (Se) deficiency is associated with cardiac and skeletal muscle dysfunction. Twenty well children aged 2-16 years (10 male) attending the Phenylketonuria (PKU) Clinic at the Royal Children's Hospital, Brisbane, had low Se levels (mean 0.29 +/- 0.02 s.e.m. mumol/L; normal range 0.56-1.16 mumol/L). Their myocardial function was assessed at rest and after exercise provocation by M-mode echocardiography in order to exclude occult left ventricular dysfunction. At rest, fractional shortening (FS) was normal (mean 38.1 +/- 1.1 s.e.m. %, n = 20). After exercise, FS increased significantly (P less than 0.001) from 37.6 +/- 1.4% to 44.3 +/- 1.2%, n = 12). This was associated with a significant rise (P less than 0.001) in heart rate (HR) from 77.3 +/- 3.1 beats/min to 125.8 +/- 5.2 beats/min (n = 12). The normal resting FS and normal increase in FS and HR with exercise is evidence against significant cardiac impairment in this group of Se-deficient children.     

Psychological and Respiratory Physiological Effects of a Physical Exercise Programme on Boys with Severe Asthma

ABSTRACT. Ten boys 9–12 years of age with severe perennial asthma participated in a physical exercise programme lasting 8 months. Pulmonary function and psychological tests were performed before training, immediately after, and one year after the end of the exercise programme. Static lung volumes, flow-volume variables and histamine tolerance were used as indicators of pulmonary function. Ego structure, body image, social development and concentration capacity were used as indicators of personality development. Before the study, the group had high FRC ( p < 0.05) and RV ( p < 0.001), low FEV₁, MEF50 and MEF25 (all p < 0.001) and low histamine tolerance. They showed marked disturbances in their personality development with low scores in psychological variables. During the training period, MEF50 and MEF25 increased slightly ( p < 0.01). Marked improvement was observed in all psychological variables ( p < 0.001). The positive effects remained during the following year. The marked and lasting improvement in personality development was regarded as an essential factor behind the more modest positive clinical and pulmonary function changes. The results emphasize the importance of including exercise programmes in the treatment of children with asthma.     

Exercise-Induced Ventricular Arrhythmia after Repair of Tetralogy of Fallot

Treadmill exercise electrocardiography (TE) was recorded in 50 patients to evaluate the incidence of exercise-induced ventricular arrhythmias (VAs) in a group of patients who underwent corrective surgery of tetralogy of Fallot (TF) more than four years previously. The results of rhythm evaluation were correlated with cardiac catheterization data as well as clinical information such as the age at surgery and the interval from surgery. Of the 50 patients tested, ventricular premature contraction (VPC) was confirmed in 12 patients (24%) on TE, while five patients (10%) demonstrated VPC on the standard ECG. The interval from surgery was significantly longer in those patients with VA (Group 1) than those without VA (Group 11) on TE (p<0.05). There was no significant difference of the age at corrective surgery between the two groups. In group I, the preoperative hemoglobin level was higher (p<0.05) and the right ventricular ejection fraction was lower (p<0.01). Exercise-induced VAs are closely related to the length of period after surgery and the depressed right ventricular function.     

Myocardial perfusion imaging with technetium-99m sestamibi SPECT in the evaluation of coronary artery disease

Technetium-99m hexakis-2-methoxy-isobutyl-isonitrile(^99mTc sestamibi) has been used for myocardial perfusion imaging in the evaluation of coronary artery disease (CAD) since 1990. The experience of its use in an Asian population with and without previous myocardial infarction (Ml), diabetes mellitus (DM), hypertension (HPT) and collateral circulation (COL) is reported. One hundred and thirty-nine patients who underwent treadmill exercise testing with ^99mTc sestamibi single photon emission computed tomography (SPECT) and coronary angiogram were studied. The overall sensitivity for the detection of CAD was 91.0% and specificity was 64.7%. For patients without previous myocardial infarction, the sensitivity was 83.8% and specificity was 83.3%. Patients with COL had a higher sensitivity while those with HPT had a lower specificity. Sensitivity was higher in patients with multi-vessel disease (MVD) than single vessel disease (SVD). The overall detection for individual artery stenosis was 74.1% with a specificity of 73.1 %. Amongst the three major coronary arteries, sensitivity was highest for the right coronary artery and specificity was highest for the left circumflex artery. Specificity was higher in patients without MI or COL. We found that the agreement between ^99mTc sestamibi SPECT and coronary angiogram for the extent of CAD was only 52.5%. The concordance rate was higher for patients with MVD than SVD. It is concluded that ^99mTc sestamibi SPECT is a sensitive and specific test for the detection of CAD and localization of disease to individual coronary arteries in our patients with some differences in the subgroups. Agreement between coronary angiogram and ^99mTc sestamibi for the extent of coronary artery disease was also satisfactory.     

心音图运动试验中的信噪比分析

为了验明ＰＣＧＥＴ方法的可信度,作者进行了该心音图运动试验中的信噪比分析。对３０个志原者进行了ＰＣＧＥＴ,运动后基带幅值的平均值与运动前基带幅值平均值的比值为１．１５０;各受试者运动后ＳＩ幅值对运动前ＳＩ幅值的倍数的平均值为１０．５７,这表明,ＰＣＧＥＴ提高了信／噪比,心内噪声、心胸系统传播过程中产生的噪声、呼吸噪声、肌肉噪声和环境噪声没有防碍ＰＣＧＥＴ的应用。ＰＣＧＥＴ可作为心力储备的无伤性、简     

Renal Function and Albumin Excretion during Exercise in Children during Remission of the Minimal Change Nephrotic Syndrome

ABSTRACT. Six patients with the minimal change nephrotic syndrome in remission and seven healthy controls were investigated with regard to renal haemodynamics and albumin excretion before, during and after exercise. The glomerular filtration rate and effective renal plasma flow were determined by a standard clearance method, employing continuous infusion of inulin and para-aminohippuric acid. Microalbuminuria was measured by an immunoturbidimetric method. The work load was standardized at 70% of the maximal working capacity and was applied for 20 min. During exercise there was a significant fall in the glomerular filtration rate and effective renal plasma flow and a significant rise in the filtration fraction. The pattern of renal haemodynamic changes did not differ between the groups. Nor was there any statistically significant difference in urinary albumin excretion, although the exercise-induced increase in albumin excretion of the controls did not reach statistical significance. It is concluded that the renal haemodynamics and urinary albumin excretion of children having long remissions of the minimal change nephrotic syndrome are normal at rest as well as during and after a submaximal exercise test.     

Pulmonary Function and Oxygen Uptake During Exercise in 16 Year Old Boys with Cystic Fibrosis

Eight of altogether 9 Norwegian boys with cystic fibrosis (CF), aged 15–17 years, and 8 healthy boys of the same age underwent pulmonary function and bicycle exercise testing. Although the CF boys showed large individual variations, the two groups showed great differences in mean body height and weight, pulmonary function variables and maximum oxygen uptake. The maximum oxygen uptake for the CF boys ranged from 40 to 125 % (mean 79 %) of predicted values. Increased ventilatory equivalent for oxygen was a characteristic finding during rest and exercise for the CF boys, and their oxygen uptake was higher during rest and corresponding work loads compared with the controls. As physical training is beneficial in cystic fibrosis, such exercise tests are of value for prescribing individual training programs and in evaluating their effects.