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Long-term prognosis in relation to ECG findings in acute myocardial infarction
Insights
Q-wave myocardial infarction indicates higher in-hospital mortality compared to non-Q-wave infarction. However, 5-year survival rates are similar for both acute myocardial infarction types. Prognosis is not improved by additional chest leads.
Area of Science:
- Cardiology
- Internal Medicine
- Diagnostic Electrocardiography
Background:
- Acute myocardial infarction (AMI) prognosis is crucial for patient management.
- Electrocardiogram (ECG) findings, specifically Q-waves, are used to classify AMI.
- The prognostic value of Q-wave versus non-Q-wave infarction requires further clarification.
Purpose of the Study:
- To investigate the 5-year prognosis of patients with acute myocardial infarction based on ECG findings.
- To compare in-hospital and long-term mortality rates between Q-wave and non-Q-wave infarctions.
- To assess the added prognostic value of 24 precordial chest leads in anterior infarction.
Main Methods:
- Retrospective analysis of 680 patients with acute myocardial infarction.
- Classification of infarction based on standard 12-lead ECG (Q-wave vs. non-Q-wave).
- Prognostic assessment using 5-year follow-up data and correlation with ECG characteristics.
Main Results:
- Q-wave infarction showed significantly higher in-hospital mortality (10.2%) than non-Q-wave infarction (1.9%).
- Five-year mortality rates were similar between Q-wave (33.6%) and non-Q-wave infarction (28.4%).
- No correlation was found between Q- and R-wave changes in 24 chest leads and 5-year mortality in anterior infarction.
Conclusions:
- Standard ECG-defined Q-wave infarction is associated with increased in-hospital mortality but not significantly different 5-year mortality compared to non-Q-wave infarction.
- The use of 24 precordial chest leads did not improve the prediction of 5-year mortality in anterior infarction.
- ECG classification of AMI has prognostic implications for short-term outcomes, but long-term survival appears comparable.
Abstract:
In 680 patients with acute myocardial infarction the prognosis during the following 5 years was related to observations made in a standard electrocardiogram (ECG) and 24 precordial chest leads. Patients with a Q-wave infarction (based on a 12-lead standard ECG) had a mortality rate during hospitalization of 10.2% which was much higher than that in patients with a non-Q-wave infarction (1.9%, p less than 0.001). At 5 years' follow-up 33.6% of those with a Q-wave infarction had died versus 28.4% of those with a non-Q-wave infarction (p greater than 0.2). Corresponding mortality rate among patients with no previous infarction (n = 587) was 32.1% and 25.2%, respectively (p = 0.17). In patients with anterior infarction and no previous infarction there was no correlation between Q- and R-wave changes in the 24 chest leads 4 days after admission to hospital and 5-year mortality rate. We thus conclude that patients with a Q-wave infarction had a higher in-hospital mortality compared with non-Q-wave infarction as judged from standard ECG, whereas 5-year mortality was similar. Similarly, there was no correlation between Q- and R-wave changes in an increased number of chest leads and 5-year mortality rate.