Exercise Studies in Tetralogy of Fallot: A Review

Abstract

Exercise evaluation of patients with congenital heart disease in general and tetralogy of Fallot in particular has had much less impact on clinical care than that of adults with coronary heart disease. Of over 4000 references on tetralogy of Fallot in the literature since 1965, only 87 involve exercise. These studies were reported from 56 institutions, with 39 originating from the United States and Canada, 40 from Europe, and 8 from Japan. They involved 3157 patients, studied mostly after intracardiac repair (ICR). In reviewing these data one is struck by the wide range of different approaches to exercise testing. This is in part related to the different purposes of each exercise study, but it also relates to the lack of uniform standards for exercise testing in patients with congenital heart disease. The studies involved maximal treadmill exercise and maximal or submaximal cycle ergometer work, in the upright or supine position, utilizing 52 different work protocols, the most common being the Bruce treadmill protocol (employed 27 times). Despite this lack of standardization exercise evaluation has significantly contributed understanding of the natural history and pathophysiology of surgically corrected tetralogy of Fallot. Work PerformanceThe majority of patients were asymptomatic when exercise tested, despite impaired exercise responses and significant residual cardiac pathology. This suggests that patient or parent assessment of physical work capacity does not correlate well with objective criteria of work performance, an impression confirmed in a study which specifically addressed this point [70]. Work capacity is best evaluated by maximal exercise. The data should be expressed as percentage of predicted known standards or simultaneously studied normal controls and/or in terms of the maximal oxygen uptake (VO 2max ), conventionally expressed in ml/min/kg body weight. For submaximal exercise tests only the determination of VO 2 at the ventricular anaerobic threshold (VAT) seems promising since VO 2 at VAT defines the limits of endurance performance and correlates well with VO 2max . Moreover, normal standards in children and adolescents have been reported [65].By objective criteria, work capacity remains markedly impaired after shunt palliation, with an average VO 2max of only 18 ml/min/kg [3,10]. In shunted patients work capacity is directly proportional to the magnitude of the systemic to pulmonary artery shunt and most limited in patients with the smallest pulmonary blood flow and the largest right-to-left shunt during exercise [24]. Following ICR there is marked improvement of the work capacity, which averaged 84.7 ± 8.8% in 20 studies (Tables 1 and 2). VO 2max averaged 36.4 ± 5.8 ml/min/kg in 45 studies, corresponding to 81% of 45 ml/min/kg, a reasonable estimate of VO 2max in untrained normal children and adolescents, as was also shown in 18 studies with normal controls (Table 2). Exercise performance varied considerably between studies. The poorest results after ICR were found in patients corrected as a...

Congenital Heart Disease in the Older Adult

“…Congenital heart lesions characterized by decreased pulmonary blood flow may hinder the growth and development of lung parenchyma and result in pulmonary hypoplasia, which may account for the restrictive pattern observed on spirometry. 174,175 Parenchymal lung disease and amiodarone-induced lung toxicity for the treatment of chronic arrhythmias are other potential intrinsic causes for the development of RLD in the ACHD population.…”

Cardiopulmonary exercise function among patients undergoing transcatheter pulmonary valve implantation in the US Melody valve investigational trial

“…24,25 Indeed, peak VO 2 in our cohort was considerably lower than that reported in past series of children and young adults with repaired TOF. [26][27][28] Lower peak VO 2 was associated with higher right-sided pressures, RV dilation, lower RVEF, and an elevated V E /VCO 2 ratio on preimplant evaluation. Similar relationships have been noted by previous investigators.…”

“…Furthermore, even after TPV and restoration of normal or near normal pulmonary valve function, the exercise capacity of the patients in their series (and ours) remained substantially lower than what was reported in previous series of postoperative patients with TOF. [26][27][28] Among patients with other congenital heart defects, a similar discrepancy between the dramatic hemodynamic effects of surgical/catheterization procedures and more modest improvements in exercise capacity have often been encountered. [36][37][38][39][40][41][42][43] This discrepancy may be related to the fact that aerobic capacity is determined by skeletal muscle function as well as cardiopulmonary function and that procedures that address only 1 component of this complex physiology without addressing the other will be of limited effectiveness.…”

Recommendations for Competitive Sports Participation in Athletes With Cardiovascular Disease: A Consensus Document From the Study Group of Sports Cardiology of the Working Group of Cardiac Rehabilitation and Exercise Physiology and the Working Group of Myocardial and Pericardial Diseases of the European Society of Cardiology

“…These are important issues to consider in patients with repaired tetralogy of Fallot or corrected and uncorrected atrial septal defect (ASD), ventricular septal defect (VSD), or atrioventricular septal defect (AVSD). 11 For instance, in tetralogy of Fallot, a gradual widening of the QRS duration of .160 ms might indicate an increased risk of sustained Adapted and modified after Mitchell et al ventricular tachycardia. A history of frequent and complex tachyarrhythmias is a reason for CHD patients to refrain from participation in competitive sports.…”