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[Ischemic preconditioning. Is it always a beneficial phenomenon?]
S C Martí Llinares1, V Pallarés Carratalá, C Capdevila Carbonell
1Unidad Cardiocirculatoria, Hospital Universitario La Fe, Valencia. scmatilli@coma.es
Revista Espanola De Cardiologia
|June 22, 1999
Summary
Myocardial stunning from brief ischemia can impair contractile function during subsequent coronary artery occlusion. This study in dogs shows preconditioning may worsen outcomes, leading to severe contractility issues.
Area of Science:
- Cardiovascular Physiology
- Myocardial Ischemia Research
- Cardiac Contractility Studies
Context:
- Ischemic preconditioning is known to reduce infarct size.
- The effect of preconditioning on myocardial contractile function post-ischemia is less understood.
- This study investigates regional contractility after a secondary ischemic event in preconditioned myocardium.
Purpose:
- To assess the impact of a later ischemic episode on the regional contractility of stunned-preconditioned myocardium.
- To analyze myocardial shortening fraction in ischemic, peri-ischemic, and control zones.
- To compare outcomes in preconditioned versus naive myocardium.
Summary:
- Mongrel dogs underwent partial, transitory coronary artery occlusion to assess myocardial function.
- Myocardium was either naive or preconditioned with brief, repeated ischemic episodes.
- Shortening fraction in the ischemic zone decreased by 107% (p < 0.01) in preconditioned dogs 5 days post-preconditioning.
Impact:
- Brief, repeated ischemia may condition contractile function negatively.
- Subsequent partial coronary flow reduction can severely affect contractility.
- Preconditioned myocardium may exhibit worsened contractility, leading to dyskinetic areas.