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Natural history of ST-segment potential distribution determined by body surface mapping in patients with acute
A J Bell1, S J Walker, D Kilpatrick
1Department of Medicine, University of Tasmania, Australia.
Insights
Body surface mapping reveals ST-segment changes after acute myocardial infarction. Anterior ST-segment depression indicates higher morbidity and angina risk in patients with inferior infarction.
Area of Science:
- Cardiology
- Medical Imaging
Background:
- Acute myocardial infarction (MI) requires understanding ST-segment behavior for prognosis.
- Body surface mapping (BSM) offers detailed electrocardiographic analysis.
- Thrombolytic therapy was not administered to the study cohort.
Purpose of the Study:
- To investigate the natural history of ST-segment changes using BSM in acute inferior MI.
- To correlate ST-segment distribution patterns with patient morbidity and outcomes.
Main Methods:
- BSM was employed in 123 patients with acute inferior MI.
- ST-segment maps were compared at different time points post-infarction (early vs. late, and months later).
- Morbidity and angina incidence were assessed in relation to ST-segment patterns.
Main Results:
- ST-segment distribution patterns showed variability over time; 46% remained unchanged.
- A significant portion of patients shifted to low-mortality (28%) or normal (7%) ST-segment patterns.
- Marked anterior ST-segment depression was associated with significantly higher morbidity (45% vs. 13%, p<0.005).
- At follow-up, anterior ST-segment depression correlated with increased angina (4/7 patients, p<0.001).
Conclusions:
- ST-segment patterns evolve after acute inferior MI, with shifts towards favorable distributions observed.
- Persistent or developing anterior ST-segment depression on BSM maps is a marker for increased morbidity and angina risk.
- BSM is a valuable tool for assessing the prognostic implications of ST-segment changes in acute MI.
Abstract:
The authors studied the natural history of the electrocardiographic ST-segment using body surface mapping in 123 patients with acute inferior infarction who were not treated with thrombolytic agents. In 91 patients they compared body surface ST-segment maps recorded at 7.9 +/- 5.4 hours after the onset of acute myocardial infarction with maps recorded at 32.6 +/- 21.6 hours after infarction. In 46% of the patients the ST-segment distribution map pattern was unchanged. Twenty-eight percent of the patients moved to a ST-segment distribution associated with low mortality, and 7% correlated with a normal ST-segment distribution. Patients who started in a group dominated by marked anterior ST-segment depression or who developed this pattern at the time of the late map had a 45% morbidity, compared to 13% for patients who never developed this pattern (p less than 0.005). In a second group of 61 patients they compared maps recorded at 15.0 +/- 15.8 hours after infarction and repeat maps 19.6 +/- 13.0 recorded months later. At follow-up mapping, 44% of the patients correlated with a normal ST-segment distribution, 38% of patients had a low-risk pattern map and in 7% the map pattern was dominated by anterior ST-segment potential depression. The latter patients had a higher morbidity than patients in the other groups, but this did not reach statistical significance. Four of seven patients in this last group had significant angina at the time of follow-up mapping, compared to 2 of 54 patients in the other two groups (p less than 0.001).