Attenuation of S-T segment elevation during repetitive coronary occlusions truly reflects the protection of ischemic preconditioning and is not an epiphenomenon

Basic Res Cardiol. 1997 Dec;92(6):426-34. doi: 10.1007/BF00796217.


Attenuation of S-T segment elevation between the first and subsequent balloon inflations of a coronary angioplasty procedure has been assumed to indicate a transition to a preconditioned state, but there has been no validation of this assumption. Open-chest rabbits were instrumented with a coronary snare and epicardial electrode. The coronary artery was occluded twice for 5 min with each occlusion followed by 10 min of reflow before a final 30 min occlusion. The evolving S-T elevation was quantitated as the voltage-time integral. For the first coronary occlusion total S-T segment elevation averaged 40.8+/-5.4 mV x min, significantly greater than 26.2+/-4.6 mV x min for the second occlusion (p < 0.001). There was no further change during the initial 5 min of the third occlusion (24.5+/-4.5 mV x min). When the protection of ischemic preconditioning was blocked by intravenous infusion of 8-(p-sulfophenyl)theophylline, an adenosine receptor antagonist, attenuation of S-T segment elevation was no longer apparent. When preconditioning was pharmacologically triggered by tyramine rather than ischemia, there also was no alteration in S-T segment elevation among the 3 occlusions. Therefore, S-T elevation was diminished during the second episode of ischemia only when a transition occurred from non-preconditioned to preconditioned state between occlusions. An attenuated S-T segment is a valid marker for the presence of the preconditioned state.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Coronary Disease / physiopathology*
  • Electrocardiography*
  • Hemodynamics / drug effects
  • Injections, Intravenous
  • Ischemic Preconditioning, Myocardial*
  • Myocardial Infarction / physiopathology
  • Rabbits
  • Reperfusion
  • Theophylline / administration & dosage
  • Theophylline / analogs & derivatives
  • Tyramine / pharmacology


  • 8-(4-sulfophenyl)theophylline
  • Theophylline
  • Tyramine