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Q waves and coronary artery disease.
Acta Medica Scandinavica
|January 1, 1979
Summary
Pathological Q waves on ECG can indicate coronary artery disease (CAD). Certain ECG changes alongside Q waves reduce their predictive value for CAD, especially in patients with angina pectoris.
Area of Science:
- Cardiology
- Diagnostic Electrocardiography
Background:
- Pathological Q waves are often associated with myocardial infarction.
- The diagnostic accuracy of Q waves for coronary artery disease (CAD) can be influenced by other electrocardiogram (ECG) findings.
Purpose of the Study:
- To evaluate the predictive value of pathological Q waves for CAD.
- To determine if specific ECG abnormalities affect the reliability of Q waves in diagnosing CAD.
Main Methods:
- Analysis of ECGs from 234 patients undergoing selective coronary arteriography.
- Comparison of CAD prevalence in patients with and without pathological Q waves.
- Assessment of the impact of left ventricular hypertrophy, prolonged QRS duration, incomplete left bundle branch block, and left axis deviation on Q wave predictive value.
Main Results:
- 78 out of 234 patients had pathological Q waves.
- In patients with Q waves and specific ECG changes (LVH, wide QRS, etc.), CAD was present in 44%.
- In patients with Q waves but without these specific ECG changes, CAD prevalence was 87% (p < 0.0005).
- Among patients without specific ECG changes, 34/35 with angina had CAD versus 6/11 without angina (p < 0.01).
Conclusions:
- Pathological Q waves are significant predictors of CAD.
- The presence of other ECG abnormalities can diminish the specificity of Q waves for CAD detection.
- Q waves are particularly reliable indicators of CAD in patients presenting with angina pectoris.