ISSN:
1435-1803
Keywords:
Ischemia
;
preconditioning
;
8-(p-sulfophenyl)theophylline
;
ST segments
;
tyramine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract 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·min, significantly antly greater than 26.2±4.6 mV·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·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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00796217
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