Determinants of beneficial effect of heparin exercise treatment on treadmill capacity and long-term efficacy of the therapy in patients with chronic effort angina.

The purpose of the present study was to evaluate the factors which influence the effect of heparin exercise treatment on treadmill capacity, and to examine the long-term efficacy of the treatment in 16 patients with chronic effort angina. Treadmill exercise was performed 20 times for 2 to 3 weeks according to standard Bruce protocol. A single intravenous dose of heparin (5,000 IU) was given 10 min before each exercise period. Exercise with heparin pretreatment increased the total exercise duration from 6.6 +/- 1.6 (SD) to 9.4 +/- 1.9 min (p < 0.05) and the maximal rate-pressure product from 19,200 +/- 4,700 to 24,700 +/- 5,900 mmHg.beats/min (p < 0.05). The rate-pressure product at the onset of angina was also increased by 32% (p < 0.05). The ST segment depression at the same exercise time as in control exercise was ameliorated from 0.16 +/- 0.05 to 0.12 +/- 0.06 mV (p < 0.05). Multivariate analysis of the determinants of the effect of the treatment on treadmill capacity indicated that the treatment is more effective in patients without previous myocardial infarction. All of the above-mentioned variables of treadmill capacity did not change significantly during a follow-up period of 13 +/- 7 months (range; 4-24 months). These findings lend further support to heparin exercise treatment as a possible therapeutic approach in patients with chronic stable effort angina, and particularly in those without previous infarction.