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Continuous ST-segment monitoring associated with infarct size and left ventricular function in the GUSTO-I trial
K G Moons1, P Klootwijk, S H Meij
1Julius Center for Patient Oriented Research, Utrecht University, The Netherlands.
Insights
Continuous ST monitoring in myocardial infarction patients reveals that ischemia intensity and duration correlate with infarct size and left ventricular ejection fraction. This supports the hypothesis that prolonged ischemia increases cardiac damage.
Area of Science:
- Cardiology
- Clinical Electrophysiology
- Cardiovascular Research
Background:
- Myocardial infarction (MI) management requires understanding factors influencing infarct size and cardiac function.
- Continuous ST monitoring offers a dynamic assessment of myocardial ischemia.
- The relationship between ischemia characteristics and clinical outcomes in MI patients needs further elucidation.
Purpose of the Study:
- To determine if the intensity and duration of myocardial ischemia, assessed by continuous ST monitoring, are associated with infarct size and left ventricular function in MI patients.
- To investigate the link between ST-trend characteristics and infarct size (Q(72)) and left ventricular ejection fraction (LVEF).
Main Methods:
- Analysis of patients from the GUSTO-I electrocardiographic substudy receiving thrombolytic therapy.
- Continuous ST monitoring using a vector-derived 12-lead ECG system.
- Linear regression analysis to correlate ST-trend characteristics (area under ST trend, area under recurrent ischemic episodes) with Q(72) and LVEF.
Main Results:
- Higher ST trend area and recurrent ischemic episodes area were significantly associated with larger infarct size (higher Q(72)).
- Higher area under recurrent ischemic episodes was significantly associated with lower left ventricular ejection fraction (LVEF).
- These associations persisted after adjusting for age, sex, infarct location, and time to treatment.
Conclusions:
- The intensity and duration of myocardial ischemia, as reflected by ST-trend analysis, are significant determinants of myocardial damage.
- Findings support the physiological hypothesis linking ischemia severity and duration to infarct size and ejection fraction in acute MI patients treated with thrombolysis.
Background:
The aim of this study was to evaluate whether in patients with myocardial infarction, the intensity and duration of myocardial ischemia as measured by continuous ST monitoring are associated with infarct size and residual left ventricular function.
Methods And Results:
The analyses included patients with myocardial infarction, receiving thrombolytic therapy, who were enrolled in the electrocardiographic substudy of GUSTO-I, monitored by a vector-derived 12-lead electrocardiographic recording system, and in whom either infarct size (defined as cumulative release of alpha-hydroxybutyrate dehydrogenase activity per liter of plasma over a 72-hour period [Q(72)]) or left ventricular ejection fraction (LVEF) was determined. With the use of linear regression analysis, we investigated the association of various ST-trend characteristics with Q(72) (206 patients) and with LVEF (180 patients). A higher area under the ST trend since thrombolysis until 50% ST recovery and a higher area under recurrent ischemic episodes (ST reelevations) were significantly associated with a higher Q(72), whereas only a higher area under recurrent ischemic episodes was significantly associated with a lower LVEF. These associations remained after adjusting for other patient characteristics such as age, sex, infarct location, and time to treatment.
Conclusions:
These findings support the physiologic hypothesis that both the intensity and duration of myocardial ischemia (both reflected by the estimated areas under the ST-trend curve) determine myocardial damage and thus are associated with infarct size and ejection fraction in patients with acute myocardial infarction who receive thrombolytic therapy.