Noninvasive diagnosis of coronary artery disease: the cardiokymographic stress test
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Cardiokymography (CKG) detects abnormal heart wall motion during exercise, improving diagnosis of coronary artery disease. This noninvasive method enhances the accuracy of stress tests by identifying false positives and negatives.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Exercise Physiology
Background:
- Coronary artery disease (CAD) diagnosis often relies on stress tests.
- Electrocardiogram (ECG) stress tests have limitations in sensitivity and specificity.
- Regional left ventricular wall motion abnormalities can indicate myocardial ischemia.
Purpose of the Study:
- To assess cardiokymography (CKG) for detecting stress-induced regional left ventricular wall motion abnormalities.
- To evaluate CKG's diagnostic accuracy compared to ECG stress testing for CAD.
- To determine if CKG improves the overall accuracy of stress testing.
Main Methods:
- Maximal treadmill exercise tests were performed on 157 patients.
- Regional left ventricular wall motion was assessed using cardiokymography (CKG).
- Coronary angiography was performed on 122 patients to confirm CAD status.
Main Results:
- CKG sensitivity for detecting abnormal wall motion was 74% (52/70 patients with CAD).
- CKG specificity for normal wall motion was 94% (49/52 normal patients).
- Concordant interpretation of ECG and CKG improved predictive accuracy compared to either test alone.
Conclusions:
- Cardiokymography (CKG) noninvasively detects regional wall motion abnormalities indicative of myocardial ischemia.
- CKG demonstrates high sensitivity and specificity in identifying coronary artery disease during stress testing.
- CKG enhances the diagnostic accuracy of ECG stress tests by identifying false-positive and false-negative results.
Abstract:
Stress-induced abnormalities of regional left ventricular wall motion were assessed by cardiokymography (CKG) during the course of maximal treadmill exercise tests in 157 patients, of whom 122 subsequently underwent coronary angiography. Seventy patients had significant angiographic coronary artery disease and 52 were normal. Forty-one of the 70 patients developed greater than 0.1 mV ST-segment depression (ECG sensitivity 59%) and 52 of 70 patients developed abnormal systolic outward motion by CKG (CKG sensitivity 74%). Among the 52 normals, 36 had negative ECG stress tests (ECG specificity 69%) and 49 had normally sustained systolic inward motion by CKG (CKG specificity 94%). The stress CKG was normal in 15 of the 16 false-positive stress ECGs; the stress ECG was correctly normal in two of the three false-positive stress CKG tests. Only one normal patient had concordantly false-positive ECG and CKG tests. The predictive accuracy of concordant ECG and CKG interpretations was, therefore, higher than either test alone. These data suggest that regional wall motion abnormalities, which are sensitive and specific markers of myocardial ischemia, may be detected noninvasively by CKG. We concluded that CKG helps identify false-positive and false-negative ECG stress tests and improves the diagnostic accuracy of stress testing for detection of coronary artery disease.