Effect of dipyridamole on the phenomenon of ischemic preconditioning in patients with ischemic heart disease during paired bicycle ergometer tests

Aim. To assess effect of dipyridamole on ischemic preconditioning (IP) in patients with coronary artery disease by paired bicycle ergometer exercise tests (BETs). Material and methods. Patients (men, n=12, age 51,7 +/- 2,5 years) with class II-III stable angina pectoris underwent paired BETs (tests 1 and 2 at 15 min intervals). Test 1 was regarded as baseline and test 2 as the preconditioning one. In 72 hours another pair of BETs was carried out (tests 3 and 4) with same time interval in between. Before second pair of tests the patients received 75 mg of dipyridamole orally. Results. Significant improvements of several parameters of ECG were observed during repeat BETs (increased exercise duration, maximal heart rate and double product, decreased maximal ST-depression and number of ECG leads with > 1 mm ST depression). These data suggested the presence of IP phenomenon in both paired BETs. However only test after dipyridamole was associated with significant increase of work load (from 82.4 +/- 10.5 to 96.4 +/- 10.1 W, p=0.033), shortening of ST-depression recovery time (from 367 +/- 45 to 254+30 s, p=0.032) and increase of increment of exercise duration (from 34 +/- 15 to 81 +/- 17 s, p=0.034). Number of ECG leads on with segment ST depression > 0,1 mv was significantly less during test 4 compared with test 2 (2.6 +/- 0.4 and 3.4 +/- 0.5; p=0.045). This data reflected increase of ischemic threshold during test 4. Conclusion. Dipyridamole (75 mg orally) augmented IP in patients with coronary artery disease during repeated BETs.