To explore the relationship between Tpeak-Tend interval (Tpe) and the extent and severity of coronary artery stenosis, and evaluate the effect of percutaneous transluminal coronary angioplasty and stent implantation (PCI) on Tpe in the patients with coronary heart disease (CHD).The ECG data were collected from 187 CHD patients undergoing coronary angiography and PCI to evaluate the extend and severity of coronary artery stenosis before and after the interventions.The Tpe of patients with severe stenosis increased significantly as compared with that in patients with moderate stenosis (138.9-/+16.2 ms vs 116.5-/+13.7 ms, P0.4). In patients with severe stenosis, the Tpe was significantly reduced at 1 h, 24 h, and 1 week after PCI (115.8-/+14.5, 92.7-/+12.9, and 88.2-/+11.3 ms, respectively, P<0.05).The Tpe can reflect the severity and range of coronary artery stenosis, which can be reduced by PCI. Tpe can be a new index for evaluating myocardial ischemia in CHD patients.