Background: Classic sulfonyloureas (SUs) are known to attenuate ischaemic preconditioning. Gliclazide is an SU agent believed to be more protective. We assessed the effects of diet, glibenclamide, or gliclazide on the warm-up effect in type 2 diabetic patients with stable angina.
Methods: The study group consisted of 64 men, aged 54+/-5 years: 17 patients without diabetes (G I) and 47 diabetic patients: 16 patients treated with glibenclamide (G II), 16 with gliclazide (G III) and 15 patients treated with diet (G IV). After the baseline positive exercise test (ET1), all patients reexercised after 30-min rest (ET2). We analysed exercise duration (ED, s), time to 1 mm ST depression (T-STD, s), max STD (mm), heart rate-systolic blood pressure product at 1 mm STD, or ischaemic threshold (mmHg/min x 100) and the total ischaemic time (s).
Results: In G I, all analysed variables improved significantly during ET2 relative to ET1. Glibenclamide (G II) completely abolished the protective effect of exercise-induced ischaemia because only ED increased during ET2 (431 vs. 451, P<0.05). In G III, however, ED (486 vs. 537, P<0.001), T-STD (364 vs. 388, P<0.05) and max STD (2.5 vs. 2.0, P<0.05) improved significantly during ET2, whereas ischaemic threshold and total ischaemic time did not (PNS). In G IV, similar to G I, all variables improved significantly during ET2 relative to ET1.
Conclusion: Warm-up effect is preserved in diabetic patients with stable angina treated with diet, partially preserved in gliclazide-treated and abolished in glibenclamide-treated patients.