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Significance of Q-wave regression after transmural acute myocardial infarction
S Coll1, A Betriu, T de Flores
1Cardiovascular Unit, Hospital Clínico, University of Barcelona, Spain.
Insights
Q-wave loss after acute myocardial infarction (AMI) is linked to better heart function and reduced risk of congestive heart failure. This suggests Q-wave disappearance may indicate a smaller infarct size.
Area of Science:
- Cardiology
- Medical Research
Background:
- Q waves on electrocardiograms (ECG) typically indicate transmural myocardial infarction.
- The prognostic significance of Q-wave loss after acute myocardial infarction (AMI) requires further investigation.
Purpose of the Study:
- To assess the prevalence and prognostic implications of Q-wave loss following transmural AMI.
- To determine if Q-wave disappearance correlates with infarct size and clinical outcomes.
Main Methods:
- A cohort of 313 patients with transmural AMI underwent heart catheterization before hospital discharge.
- Patients were followed for a mean of 65 months to track Q-wave changes on ECG and clinical outcomes.
- Peak creatine kinase levels and left ventricular function were assessed.
Main Results:
- 11% of patients lost their Q waves within 14 months post-AMI.
- Q-wave loss was associated with lower peak creatine kinase levels, improved left ventricular ejection fraction, and fewer abnormal heart segments.
- Patients with Q-wave loss had a significantly lower incidence of congestive heart failure compared to those with persistent Q waves.
- No significant differences in mortality, reinfarction, or new angina were observed between groups.
Conclusions:
- Q-wave loss after AMI may indicate a smaller infarct size.
- Q-wave disappearance is associated with favorable left ventricular remodeling and reduced risk of congestive heart failure.
Abstract:
A total of 313 consecutive patients was studied to assess the prevalence and prognostic implications of Q-wave loss after transmural acute myocardial infarction. Heart catheterization, including single-plane left ventriculography and selective coronary arteriography, was performed before hospital discharge. After a mean follow-up of 65 (1 to 100) months, 34 patients (11%) lost their Q waves. The time interval from the acute event to the first electrocardiogram showing Q-wave disappearance was 14 (1 to 32) months. Peak creatine kinase value was significantly higher in patients who retained their Q waves than in those who lost them (1,121 +/- 813 vs 779 +/- 464 IU, respectively, p less than 0.05). Severity of coronary artery disease, as judged by the number of diseased arteries and the number of arteries with total or subtotal occlusion, was similar in both groups. However, patients showing Q-wave regression had lower left ventricular end-diastolic pressure, higher ejection fraction and fewer abnormally contracting segments than their counterparts (12 +/- 6 vs 15 +/- 7 mm Hg, p less than 0.05; 53 +/- 11 vs 44 +/- 14%, p less than 0.001; 1 +/- 1 vs 2 +/- 1 segments, p less than 0.001, respectively). In addition, no patient with normalized electrocardiogram presented with left ventricular aneurysm. Although differences in mortality, nonfatal reinfarction and new onset of angina between the 2 groups were not significant, congestive heart failure was prevalent among patients with permanent Q waves (23 vs 6%, p less than 0.05). Our findings suggest that Q-wave loss after AMI may be related to a smaller infarct size.