Background-Although some patients with adult congenital heart disease (ACHD) report limitations in exercise capacity, we hypothesized that depressed exercise capacity may be more widespread than superficially evident during clinical consultation and could be a means of assessing risk. Methods and Results-Cardiopulmonary exercise testing was performed in 335 consecutive ACHD patients (age, 33Ϯ13 years), 40 non-congenital heart failure patients (age, 58Ϯ15 years), and 11 young (age, 29Ϯ5 years) and 12 older (age, 59Ϯ9 years) healthy subjects. Peak oxygen consumption (peak V O 2 ) was reduced in ACHD patients compared with healthy subjects of similar age (21.7Ϯ8.5 versus 45.1Ϯ8.6; PϽ0.001). No significant difference in peak V O 2 was found between ACHD and heart failure patients of corresponding NYHA class (PϭNS for each NYHA class). Within ACHD subgroups, peak V O 2 gradually declined from aortic coarctation (28.7Ϯ10.4) to Eisenmenger (11.5Ϯ3.6) patients (PϽ0.001). Multivariable correlates of peak V O 2 were peak heart rate (rϭ0.33), forced expiratory volume (rϭ0.33), pulmonary hypertension (rϭϪ0.26), gender (rϭϪ0.23), and body mass index (rϭϪ0.19). After a median follow-up of 10 months, 62 patients (18.5%) were hospitalized or had died. On multivariable Cox analysis, peak V O 2 predicted hospitalization or death (hazard ratio, 0.937; Pϭ0.01) and was related to the frequency and duration of hospitalization (Pϭ0.01 for each). Conclusions-Exercise capacity is depressed in ACHD patients (even in allegedly asymptomatic patients) on a par with chronic heart failure subjects. Lack of heart rate response to exercise, pulmonary arterial hypertension, and impaired pulmonary function are important correlates of exercise capacity, as is underlying cardiac anatomy. Poor exercise capacity identifies ACHD patients at risk for hospitalization or death. (Circulation. 2005;112:828-835.)

Pulmonary regurgitation (PR) is a common complication after surgical or percutaneous relief of pulmonary stenosis and following repair of tetralogy of Fallot. Significant PR is usually well tolerated in childhood. However, in the long term, chronic PR has a detrimental effect on right ventricular (RV) function and exercise capacity and leads to an increased risk of arrhythmia and sudden cardiac death (SCD). Recent advances in non-invasive imaging and, in particular, wider availability of cardiovascular magnetic resonance (CMR), have improved the assessment of PR and RV function in these patients. This in turn has facilitated decision making on the optimal timing for elective pulmonary valve replacement (PVR), which should be performed before irreversible RV dysfunction ensues.

Pulmonary arterial thrombosis among adults with Eisenmenger syndrome is common and relates to older age, biventricular dysfunction, and slow pulmonary artery blood flow rather than degree of cyanosis or coagulation abnormalities. Further work to define treatment efficacy is needed.