Maximal exercise stress testing in normal and hyperlipidemic children

Treadmill exercise in Neopolitan children and adolescents

Two hundred and eighty healthy children from Naples, Italy (140 boys and 140 girls) aged 4-17 years were studied using Bruce walking treadmill protocol to voluntary exhaustion. Endurance time and double product increased with age. Systolic blood pressure increased linearly during the test. Multivariate analysis showed that body weight and age were the best predictors of endurance time. Endurance time averaged 15.2 +/- 2.8 min in boys and 13.7 +/- 2.3 min in girls (p = 0.00001). Mean +/- SD double product at peak exercise was 264.3 +/- 63 (boys) and 242 +/- 44 (girls) (p = 0.01). Sinus arrhythmia was present in 78% of the children and disappeared at a mean heart rate of 112 +/- 16 beats/min during exercise. The voltage of the R wave on V4 lead decreased in all but four children during the test (delta R = -0.25 +/- 0.24 mV). The P and T waves increased in almost all children. No ST depression or upward sloping was detected. The voltage of the PR isoelectric line remained constant. The J point was displaced downwards in 78% of children, unchanged in 11% and displaced upwards in the remaining 11% of the children. The present study gives reference parameters for a walking treadmill test in Southern European children.

Detecting arrhythmia by exercise electrocardiography in pediatric patients: assessment of sensitivity and influence on clinical management

We studied 49 patients with suspected arrhythmias (group 1) and 92 patients with previously documented arrhythmias (group 2) who underwent exercise electrocardiography (EECG) at our institution between 1979 and 1987. Among group 1 patients, all of whom had sinus rhythm before exercise, 10 (20%) had abnormal findings on EECG, and treatment was modified in 4 of these 10 (8% of group 1). Further testing (24-hour ambulatory or transtelephonic electrocardiographic monitoring or electrophysiologic study) of the 39 patients with normal EECG findings revealed 8 additional patients with arrhythmias. In group 1, the sensitivity of EECG was 56%, and its negative predictive value was 79%. Group 2 consisted of 38 patients with atrial arrhythmias, 31 with ventricular arrhythmias, and 23 with atrioventricular conduction abnormalities before EECG. Of these 92 patients, 68 (74%) had abnormal EECG findings. All but 1 of the 24 patients with normal findings underwent further testing, and rhythm abnormalities were induced in 16. Patients with atrial arrhythmias were more likely to have normal EECG results (42%) than were those with ventricular arrhythmias (23%) or an atrioventricular conduction abnormality (4%). Of the 35 patients who had been referred for suppression of an arrhythmia, 25 (71%) had abnormal rhythm suppressed during exercise. Clinical management was modified in 27% of group 2 patients on the basis of EECG findings.

Aortic valve replacement in childhood: evaluation of left ventricular function by electrocardiography, echocardiography and graded exercise testing

Preoperative and postoperative left ventricular (LV) performance was evaluated noninvasively in 15 children who survived aortic valve replacement (AVR). The noninvasive evaluation included electrocardiography, M-mode echocardiography, and graded exercise testing. Clinically, there was dramatic improvement postoperatively: All but 2 patients were asymptomatic. No conduction defects or arrhythmias were detected preoperatively; however, in the late postoperative period there was a variety of intraventricular conduction abnormalities, myocardial infarctions, and ventricular or supraventricular arrhythmias. On M-mode echocardiography, children with aortic stenosis continued to have increased LV mass postoperatively. Shortening fraction and left-sided systolic time intervals returned to normal. The children with aortic regurgitation also had persistently abnormal LV mass on echocardiography postoperatively. Exercise data indicated no improvement in working capacity after AVR. Also, 9 children (63%) continued to have ST-segment depression with maximal exercise. These data indicate that AVR does not result in a return to normal of myocardial performance in children with severe aortic valve disease.

Responses of normal children and young adults to controlled bicycle exercise

Exercise responses were obtained from 149 children and young adults (average age 14.5 years) and divided by sex and body surface area (BSA): children with BSA less than 1 m2; children with BSA 1--1.19 m2; males with BSA greater than or equal to 1.2 m2; and females with BSA greater than or equal to 1.2 m2. Total work, mean and maximal power outputs were more affected by body size (height) than age in children with BSA less than 1 m2 and in males and females with BSA greater than or equal to 1.2 m2. Mean systolic pressure increased up to 64% above the preexercise supine value at peak effort, with the level of mean maximal systolic pressure having a positive relationship with body size (height), power output and preexercise sitting systolic pressure in all subgroups except children with BSA 1--1.19 m2. Mean diastolic pressure increased up to 24% above the preexercise supine value at peak effort. ST-segment depression of 1--2 mm was recorded in 12.1% (18 of 149) of the population at peak exercise. These changes occurred in 8.9% of all males and in 16.9% of all females (p greater than 0.1). The data from this study reveal the importance of sex and body size in the clinical interpretation of exercise responses in growing subjects, provide a reference for objective evaluation of subjects with or without cardiac abnormalities and provide a guide for careful monitoring of subjects during an exercise study.