Extent of ST-segment depression and cardiac events in non-ST-segment elevation acute coronary syndromes
Stefano Savonitto1, Mauricio G Cohen, Alessandro Politi
1Dipartimento Cardio-toraco-vascolare, 'A. De Gasperis', Ospedale Niguarda Ca' Granda, Piazza Ospedale Maggiore 3, 20162 Milan, Italy. stefano.savonitto@fastwebnet.it
Insights
The extent of ST-segment depression on an electrocardiogram (ECG) predicts 30-day mortality in non-ST-segment elevation acute coronary syndromes (NSTE ACS). Greater ST depression indicates higher risk and correlates with more severe coronary artery disease.
Area of Science:
- Cardiology
- Clinical Medicine
- Diagnostic Imaging
Background:
- The prognostic value of electrocardiogram (ECG) changes in non-ST-segment elevation acute coronary syndromes (NSTE ACS) is established, but the precise relationship between the extent of ischemic changes and short-term risk remains unclear.
- Risk stratification is crucial for timely intervention in NSTE ACS patients.
Purpose of the Study:
- To investigate the independent predictive value of the extent of myocardial ischemia, as assessed by admission ECG, for short-term risk stratification in patients with NSTE ACS.
- To determine if quantitative ECG measures correlate with the severity of coronary artery disease (CAD) and short-term adverse outcomes.
Main Methods:
- Analysis of admission ECGs from 5192 NSTE ACS patients in the GUSTO-IIb trial.
- Quantification of ST-segment depression, T-wave inversion, and ST-segment elevation.
- Multivariable logistic regression models incorporating clinical, enzymatic, and ECG variables to assess independent predictors of 30-day outcomes.
Main Results:
- The sum of ST-segment depression across all leads was a powerful independent predictor of 30-day all-cause mortality (P<0.0001).
- Increasing extent of ST-segment depression correlated with a continuous increase in mortality risk.
- ST-segment depression, minimal anterior ST-segment elevation, and minimal inferior ST-segment elevation independently predicted a composite of death, myocardial infarction, or reinfarction.
- ST-segment depression extent strongly correlated with the prevalence of three-vessel or left main coronary disease and peak creatine kinase levels.
Conclusions:
- In NSTE ACS patients, the sum of ST-segment depression on the admission ECG is a potent independent predictor of 30-day mortality.
- The extent of ST-segment depression correlates with the severity of underlying coronary artery disease.
- Minimal ST-segment elevation (<1 mm) in anterior or inferior leads is also independently associated with adverse outcomes.
Aims:
We sought to determine whether the extent of myocardial ischaemia on the admission electrocardiogram (ECG) has independent predictive value for short-term risk stratification of patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS). Although the presence of ischaemic ECG changes on admission has been shown to predict outcome, the relationship between the extent of ECG changes and the risk of cardiac events is still ill defined.
Methods And Results:
We analysed the admission ECGs of 5192 ACS patients enrolled in the GUSTO-IIb trial, without an ECG indication for thrombolysis. ECG tracings showing one or more of the following were eligible: ST-segment depression >0.5 mm, T-wave inversion >1 mm, and ST-segment elevation >0.5 mm but <1 mm. ECG variables associated with unfavourable 30 day outcomes in a univariable analysis were further assessed in a multivariable logistic regression model including independent clinical predictors. In the multivariable clinical, enzymatic, and ECG model, the sum of ST-segment depression (in millimetres) in all leads was a powerful independent predictor of 30 day death (P<0.0001), with a continuous increase in risk with the extent of ST-segment depression. The sum of ST-segment depression (P<0.0001) and the presence of minimal inferior ST-segment elevation (P<0.0001) or anterior ST-segment elevation (P=0.0182) were also independent predictors of the composite of death and myocardial infarction or reinfarction. The extent of ST-segment depression showed a highly significant correlation with the prevalence of three-vessel (P<0.0001) or left main coronary disease (P<0.0001), and also with the peak levels of creatine kinase (P<0.0001) during the index episode of ACS.
Conclusion:
In patients with NSTE ACS, the sum of ST-segment depression in all ECG leads is a powerful predictor of all-cause mortality at 30 days, independent of clinical variables and correlates with the extent and severity of coronary artery disease. The presence of even minimal (<1 mm) ST-segment elevation in anterior or inferior leads is independently associated with adverse outcomes.
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