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Pathologic implications of restored positive T waves and persistent negative T waves after Q wave myocardial
Objectives:
We sought to study the pathologic implications of restored positive T waves and persistent negative T waves in the chronic stage of Q wave myocardial infarction.
Background:
Some inverted T waves (coronary T waves) become positive after acute myocardial infarction; others retain their negative T wave component for a long time. The pathologic implications of the difference between restored positive T waves and persistent negative T waves in leads with Q waves has not, until now, been given much careful study.
Methods:
Of 17 patients with anterior or anteroseptal myocardial infarction confirmed by autopsy, 8 (group P) had positive and 9 (group N) had negative T waves in precordial leads with Q waves > or = 1 year after the onset of myocardial infarction. The appearance and extent of the infarct area and the degree of coronary artery stenosis were evaluated in both groups.
Results:
At autopsy, seven of eight patients in group P had nontransmural fibrotic changes in the anteroseptal or anterior wall. However, seven of nine patients in group N had a transmural myocardial infarction consisting of only a thin fibrotic layer in the anteroseptal or anterior wall. The left anterior descending coronary artery showed 75% stenosis in 1 patient in each group but > 90% stenosis in the remaining 15 patients.
Conclusions:
Persistent negative T waves in leads with Q waves in the chronic stage of myocardial infarction indicate the presence of a transmural infarction with a thin fibrotic layer, whereas positive T waves indicate a nontransmural infarct containing viable myocardium within the layer.