Key Points
- To determine the relationship between early epicardial ST-segment changes, regional myocardial blood flow, and the extent of myocardial ischemic injury.
- Conducted left anterior descending coronary artery ligation in 12 anesthetized dogs.
- Measured regional myocardial blood flow using radioactive microspheres (15 µm) at 15 minutes and 24 hours post-occlusion.
- Assessed ischemic damage severity by measuring myocardial creatine phosphokinase activity depletion 24 hours after coronary ligation alongside epicardial electrocardiographic recordings.
- Myocardial creatine phosphokinase activity correlated strongly with regional myocardial blood flow at 15 minutes (r=0.93, 2P < 0.001) and 24 hours (r=0.88, 2P < 0.001).
- Acute epicardial ST-segment elevation correlated weakly with early blood flow (r=-0.41, 2P < 0.001), late blood flow (r=0.35, 2P < 0.05), and 24-hour creatine phosphokinase depletion (r=-0.36, 2P < 0.02).
- Approximately 35% of central infarct zones with severe blood flow reduction (one-tenth of normal) and 44% of areas developing pathological Q-waves lacked acute ST-segment elevation at 15 minutes.
Structured PICO
PPopulation12 anesthetized dogs
IInterventionLeft anterior descending coronary artery ligation
OOutcomeCorrelation between acute epicardial ST-segment elevation and severity of myocardial damage (assessed by myocardial creatine phosphokinase depletion) at 24 hourssurrogate
In a canine model of coronary occlusion, early epicardial ST-segment elevation did not reliably predict the severity of ultimate myocardial damage.