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Effects of isometric handgrip and dynamic exercise on left-ventricular function
Insights
Bicycle exercise is superior to handgrip stress for detecting coronary artery disease. Radionuclide angiocardiography revealed that bicycle exercise effectively identifies left-ventricular dysfunction, unlike handgrip stress.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Diagnostic Imaging
Background:
- Assessing cardiac function is crucial for diagnosing coronary artery disease (CAD).
- Non-invasive methods like radionuclide angiocardiography (RNA) are used to evaluate cardiac performance under stress.
- Comparing different stress modalities is essential for optimizing diagnostic accuracy.
Purpose of the Study:
- To compare the efficacy of isometric handgrip and bicycle exercise stress tests in conjunction with radionuclide angiocardiography for detecting coronary artery disease.
- To evaluate the impact of each stress modality on left-ventricular function and cardiac output in normal subjects and CAD patients.
Main Methods:
- Radionuclide angiocardiography was performed on 10 healthy volunteers and 20 patients with documented CAD.
- Cardiac function was assessed during two stress conditions: isometric handgrip and bicycle exercise.
- Key parameters evaluated included cardiac output, heart rate, left-ventricular ejection fraction, and regional wall motion abnormalities.
Main Results:
- Isometric handgrip induced a minor increase in cardiac output with no significant change in left-ventricular function; wall motion abnormalities were detected in only 45% of CAD patients.
- Bicycle exercise in normal subjects showed an increased left-ventricular ejection fraction with stable cardiac volumes.
- Failure to increase left-ventricular ejection fraction by ≥0.05 during bicycle exercise accurately identified 19 of 20 CAD patients, with no false positives.
Conclusions:
- Bicycle exercise elicits a more pronounced cardiovascular response compared to isometric handgrip stress.
- Bicycle exercise, when combined with radionuclide angiocardiography, is a more effective stress modality for detecting left-ventricular dysfunction indicative of coronary artery disease.
Abstract:
Radionuclide angiocardiography was used to assess cardiac function during isometric handgrip and bicycle exercise in ten normal volunteers and in 20 patients with documented coronary artery disease. Handgrip stress evoked a small increase in cardiac output that resulted from a concomitant increase in heart rate and no change in left-ventricular function. The most reliable criterion for diagnosis of coronary artery disease by handgrip was development of a new well-motion abnormality. However, abnormal wall motion was observed in only 45% of patients with coronary artery disease and in one of the ten normal subjects. In normal subjects, left ventricular function during bicycle exercise was characterized by an increase in left-ventricular ejection fraction with little change in cardiac volumes. The failure to increase left-ventricular ejection fraction by at least 0.05 identified 19 to 20 patients with coronary artery disease with no false positives. Therefore, bicycle exercise evokes a more dramatic cardiovascular response than handgrip stress and is the preferable stress modality for inducing abnormalities of left-ventricular function for detection of coronary artery disease.