We performed a pilot study to assess the significance of modest, asymptomatic, elevated serum cardiac markers – troponin T (TnT) and creatinine kinase-MB (CK-MB) – 18–24 h following successful elective percutaneous coronary intervention (PCI) and to explore their relationship with changes in aerobic exercise capacity, as measured by peak oxygen consumption (VO<sub>2</sub>), 6 weeks following the procedure. Twenty-three patients with single-vessel disease and chronic angina performed an incremental cardiopulmonary exercise test before and 6 weeks after successful uncomplicated PCI. A venous blood sample was taken at rest before PCI and 18–24 h after the procedure. Successful PCI resulted in a trend towards an increased peak VO<sub>2</sub> [21.62 ± 0.64 (pre) vs. 23.03 ± 0.75 ml/ kg/min (post), p = 0.07; mean ± SEM]. There was a significant increase [median (IQR)] in TnT, from 0.00 (0.00) µg/l at baseline increasing to 0.02 (0.03) µg/l at 18–24 h, p = 0.002. CK-MB levels showed no significant difference. In the group of 15/23 (65%) patients with an elevation in serum TnT (≧0.01 µg/l), 18–24 h after successful PCI, there was no significant increase in peak VO<sub>2</sub> [23.31 ± 0.96 (pre) vs. 23.89 ± 1.09 ml/kg/min (post), p = 0.57]. In 8 (35%) patients with no rise in TnT at 18–24 h, a significant increase in peak VO<sub>2</sub> was observed following successful PCI [23.10 ± 0.91 (pre) vs. 25.09 ± 0.75 ml/kg/min (post), p = 0.02]. Although 7 of these 8 patients increased their peak VO<sub>2</sub>, the absence of a TnT rise at 18–24 h was not significantly associated with an increase in peak VO<sub>2</sub> following successful PCI (p = 0.18). To confirm these interesting initial results and investigate the relationship of serum cardiac markers following successful PCI and subsequent exercise capacity, further studies are required.