['Attempts to demonstrate preconditioning during repeated angioplasty balloon inflations (BIs) have not been universally successful. The main obstacle is that the first BI is unreliable, due to the variable degrees of occlusion by the deflated balloon. In the present study, we examined whether ST segment elevation decreases and evaluated its relation to collateral recruitment during repeated angioplasty BIs in the pig.', 'Twenty male pigs, 7 months old, under general anesthesia, underwent 3 repeated BIs of 120 s, with a 5-min interval between them, in the left anterior descending artery or the right coronary artery. A pressure wave wire was used for the measurement of coronary wedge pressure and to obtain the intracoronary ST segment elevation. Intracoronary ST segment elevation was 1.97 +/- 0.76 mV during the 1st BI, 2.09 +/- 0.82 mV during the 2nd BI and 1.84 +/- 0.82 mV during the 3rd BI (p = n.s.). Coronary wedge pressure was 12 +/- 6, 18 +/- 18 and 20 +/- 20 mm Hg (p < 0.05 vs. 1st BI) during the 3 BIs, respectively.'] Do repeated balloon inflations diminish ST segment elevation even though coronary collateral recruitment is promoted in pigs?