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Correlation of abnormal Q waves, coronary pathology, and ventricular contractility
Insights
Electrocardiogram Q-waves accurately indicate coronary artery disease severity and ventricular dysfunction. Normal ECGs in patients with critical coronary occlusions often show normal ventriculograms, suggesting ECGs correlate better with ventricular function than coronary pathology.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Medical Electrography
Background:
- Coronary artery disease (CAD) diagnosis relies on correlating clinical findings with imaging and electrical activity.
- Electrocardiograms (ECG) provide insights into myocardial health, but their correlation with coronary pathology and ventricular function requires precise definition.
Purpose of the Study:
- To investigate the correlation between significant Q-waves on electrocardiograms (ECG) and critical coronary occlusions (≥75% obstruction).
- To assess the relationship between Q-waves, ventriculographic abnormalities, and ventricular contractility in patients with coronary artery disease.
- To evaluate the diagnostic value of normal and abnormal ECGs in predicting ventriculographic findings in the presence of critical coronary occlusions.
Main Methods:
- Analysis of electrocardiograms, coronary arteriograms, and ventriculograms from 492 patients with coronary artery disease.
- Correlation of significant Q-wave presence and location with the degree of coronary artery obstruction and ventricular contractility.
- Comparison of ECG findings with ventriculographic results in patients with both critical coronary occlusions and normal ECGs.
Main Results:
- Significant Q-waves demonstrated strong correlation (77-87%) with critical coronary occlusions and ventriculographic abnormalities, except in true posterior myocardial infarction (55%).
- Specific ECG lead combinations (II, III, aVF) showed varying degrees of accuracy in predicting ventriculographic abnormalities.
- In patients with critical coronary occlusions and normal ECGs, ventriculograms were normal in 71-78% of cases, indicating ECGs correlate better with ventricular function than coronary pathology.
Conclusions:
- Significant Q-waves on ECG are reliable indicators of critical coronary occlusions and associated ventricular dysfunction.
- The diagnostic accuracy of Q-waves varies by myocardial region, with true posterior infarction showing lower correlation.
- Normal ECGs in the context of significant coronary artery disease correlate more closely with normal ventricular function than with the extent of coronary pathology.
Abstract:
Four hundred and ninety-two patients with coronary artery disease underwent analysis of their electrocardiograms, coronary arteriograms, and ventriculograms. Significant Q-waves were correlated with critical coronary occlusions (greater than or equal 75 per cent obstruction) and ventricular contractility. It was found that Q-waves correlate equally well with ventriculographic abnormalities and critical coronary occlusions. The Q-wave correlation varied from 77 to 87 per cent, depending on the area of myocardium under consideration, except for true posterior myocardial infarction, which correlated 55 per cent with ventriculographic abnormalities and 55 per cent with critical coronary occlusions. Significant Q-waves in Leads II, III, and aVF are better indicators of ventriculographic abnormality than in Leads III and aVF alone, whereas Q-waves in the latter two leads are more definitive than in Lead III alone. Patients who have critical coronary occlusions and normal electrocardiograms have normal ventriculograms in 71 to 78 per cent of the cases, again depending on the area of the myocardium under consideration. Thus, the normal electrocardiogram correlates better with the ventriculogram than with coronary pathology. The abnormal electrocardiogram correlates equally well with both.