Exercise performance after repair of anomalous origin of the left coronary artery from the pulmonary artery.

Abstract

Eleven patients underwent exercise testing after operative repair of anomalous origin of the left coronary artery from the pulmonary artery. Five patients repaired after 2 years of age comprised a childhood surgery group, and six patients repaired before 2 years of age comprised an infant surgery group. All patients were exercised using either a treadmill or electronically braked bicycle with simultaneous thallium 201 scintigraphy. Oxygen consumption, carbon dioxide production, pulmonary functions, and electrocardiogram were all monitored continuously. Pulmonary reserve was normal in all patients. Based on heart rate reserve, respiratory exchange ratio, and oxygen-consumption response to work load, two patients in the infant surgery group stopped exercise before achieving maximum aerobic capacity. All remaining patients achieved their maximum aerobic capacity. There was no difference in work rate or oxygen consumption during exercise between the infant and childhood surgical group. Four patients (two in each surgical group) had an impaired chronotropic response to exercise. Three of these four patients demonstrated perfusion defects by thallium scintigraphy. Thallium scintigraphy was normal in all remaining patients. Electrocardiographic abnormalities were noted in seven of 11 patients having ventricular arrhythmias or ST segment depression. It is concluded from this study that exercise performance after repair of anomalous origin of the left coronary artery from the pulmonary artery is not affected by the age at which surgery is performed. Exercise is frequently associated with electrocardiographic evidence of abnormal myocardial perfusion despite frequently negative simultaneous 201TI scintigraphy. (Circulation 1990;81:1287-1292 Anomalous left coronary artery arising from the pulmonary artery is a rare defect explaining fewer than 0.1% of new cases of congenital heart disease. It frequently results in congestive heart failure secondary to myocardial ischemia and subsequent infarction in early infancy.' The need for surgery, the timing of surgery, and the type of operation for these patients have been debated for years. There seems to be a general consensus that establishing a two coronary artery system is preferable to assure adequate myocardial perfusion.1-7To aid in the evaluation of cardiac function of patients with anomalous origin of the left coronary from the pulmonary artery, this study evaluated the exercise performance of a group of patients who had undergone surgical repair of this defect. We evaluated From the Divisions

Is the Chronotropic Index Applicable to Children and Adolescents?

“…11 Chronotropic incompetence is also seen in children and adolescents who have undergone intracardiac repair for congenital heart disease, [12][13][14][15][16][17][18][19] those with congenital long QT syndrome, 20,21 recipients of cardiac transplantation, 26 and patients with anorexia nervosa. 27 Although the clinical significance of chronotropic incompetence in the paediatric populations is still unclear, chronotropic incompetence is present many years before heart disease develops.…”

“…6,28 Diagnosis of chronotropic incompetence in children and adolescents is almost exclusively based on a failure to reach standard heart rate at peak exercise. [13][14][15][16][17][18][19][20][21]29 However, when paediatricians interpret the data of paediatric exercise testing with low values of peak heart rate, it is often difficult to distinguish poor motivation from a true chronotropic response because poor effort will result in early test termination. Therefore, rather than the measurements obtained from maximal exercise, clinically valuable information on exercise testing in children and adolescents often lies in the submaximal phases.…”

“…22,23 To our knowledge, however, the clinical diagnosis of chronotropic incompetence in children and adolescents is almost exclusively based on a failure to reach standard heart rate at peak exercise or at each stage of treadmill testing as estimated according to age and sex. [13][14][15][16][17][18][19][20][21]24 Therefore, in the present study we tested the hypothesis that the CRI is not influenced by exercise intensity, and is also independent of Circulation Journal Vol.69, April 2005 age, sex, functional capacity, and resting heart rate in young patients. …”

“…11 Chronotropic incompetence is also seen in children and adolescents who have undergone intracardiac repair for congenital heart disease, [12][13][14][15][16][17][18][19] or who have congenital long QT syndrome. 20,21 The chronotropic response in adults is assessed by the chronotropic index (CRI), which utilizes the linear relationship between heart rate reserve and metabolic reserve during incremental exercise testing, 22,23 and this has become the standard method.…”

“…44 (16) 46 (12) Resting heart rate (beats/min) 79 (10) 81 (13) Peak heart rate (beats/min) 198 (8) 199 (13) Peak oxygen uptake (ml·kg -1 ·min -1 ) 47. 2 (9.9) 39.…”