[Warm-up angina and the application of a KATP channel blocker]

To explore the protection for ischemic myocardium with warm-up phenomenon and KATP channel blocker interventional effect on it.

Patients with chronic stable angina who came into the study were divided into three groups according to the presence of diabetes and its treatment ways: 25 patients without diabetes came into a NDM group, 22 patients with diabetes treated with glibenclamide came into a DMG group and 25 patients with diabetes but on diet only came into a DMD group. All the patients underwent sequential bicycle ergometer exercise test twice (EX1, EX2) with a time interval of 15 min. Parameters including exercise duration (ED), time for 1 mm ST-segment depression (T-STD), maximum STD (mm) and corresponding heart-rate systolic blood pressure product (RPP) were observed respectively. The parameters obtained during EX2 were compared with those obtained during EX1.

In the group NDM, ED and T-STD were prolonged [(546.04 +/- 103.78) s vs (617.52 +/- 106.96) s, P < 0.05 and (378.64 +/- 92.34) s vs (436.84 +/- 91.25) s, P < 0.05], STDmax was shortened [(2.06 +/- 0.37) mm vs (1.75 +/- 0.41) mm, P < 0.01] and RPP was increased [(173.77 +/- 34.73) beatsxmin(-1)xmm Hg(-2) vs (199.23 +/- 37.07 beatsxmin(-1)xmm Hg(-2), P < 0.05] as the parameters during EX2 were compared with those during EX1. In the group DMG, there was no difference in these analysed parameters except that T-STD was prolonged [(328.45 +/- 64.66) s vs (363.00 +/- 81.48) s, P < 0.01] when those of EX2 and EX1 were compared. In the group DMD, all the analysed parameters improved significantly during the second test (EX2) in comparison with the first test (EX1) as the results in the group NDM.

Exercise test can induce warm-up phenomenon in patients with chronic stable angina pectoris. The KATP channel blocker glibenclamide can block the warm-up phenomenon.