Related Experiment Videos
Comparison of coronary hemodynamic and cardiac metabolic alterations during coronary artery spasm associated with ST
Insights
ST elevation during coronary vasospasm indicates more severe myocardial ischemia than ST depression, evidenced by significantly reduced coronary blood flow and lactate extraction. This suggests a spectrum of vasospastic disorders.
Area of Science:
- Cardiology
- Physiology
Background:
- Coronary vasospasms are typically indicated by ST elevation or depression on an electrocardiogram (ECG).
- The differential severity of myocardial ischemia between ST elevation and depression in vasospasm remains debated.
Purpose of the Study:
- To test the hypothesis that ST elevation signifies more severe myocardial ischemia than ST depression.
- To investigate the relationship between ECG changes and hemodynamic/metabolic markers of ischemia during coronary vasospasm.
Main Methods:
- Assessed coronary sinus blood flow (CSBF) and transcardiac lactate extraction ratio (LER) in 19 patients with focal coronary vasospasm.
- Induction of vasospasm using ergonovine, differentiating between ST elevation and ST depression events.
Main Results:
- ST elevation events showed a significant decrease in CSBF (97 to 79 ml/min) and a marked reduction in LER (29% to -14%).
- ST depression events exhibited less pronounced changes in CSBF and LER compared to ST elevation events.
- These findings suggest ST elevation is associated with more severe reductions in coronary blood flow and myocardial ischemia.
Conclusions:
- Coronary vasospasm with ST elevation is linked to more significant reductions in coronary blood flow and more severe myocardial ischemia.
- The findings support the view that ST elevation and depression in vasospastic disorders represent a continuous spectrum of ischemic severity.
Abstract:
Coronary vasospasms are usually indicated by ST elevation or depression in the electrocardiogram (ECG). To test the hypothesis that ST elevation represents more severe myocardial ischemia than does ST depression, we determined the coronary sinus blood flow (CSBF) and the transcardiac lactate extraction ratio (LER) in 19 selected patients who had focal vasospasms in the left anterior descending artery. In 10 patients, ergonovine (0.11 +/- 0.02 mg, mean +/- SEM) provoked severe (total or subtotal) coronary vasospasm with ST elevation. Under these conditions, CSBF significantly decreased (from 97 +/- 8 ml/min to 79 +/- 5 ml/min, p less than 0.01) with a marked reduction in LER (from 29 +/- 5% to -14 +/- 6%, p less than 0.01). In contrast, 10 vasospastic events with ST depression after ergonovine (0.15 +/- 0.04 mg, NS) were recognized as mild spastic narrowing or severe spasms with well developed collateral circulation. Alteration of CSBF was significant in only a few patients and the overall CSBF response was non-significant (from 106 +/- 12 ml/min to 103 +/- 13 ml/min). The reduction in LER in this group was less pronounced than those in patients with ST elevation (p less than 0.05). These results indicate that coronary vasospasm with ST elevation may be related to the more pronounced reduction in coronary blood flow accompanied by more severe myocardial ischemia. Such observations may support the contention that some ischemic events associated with ST elevation or depression can be interpreted as a continuous spectrum of vasospastic disorders.