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Effects of coronary artery bypass grafting on left ventricular function assessed by multiple gated ventricular
Insights
Coronary artery bypass grafting significantly improves exercise-induced left ventricular function in stable angina patients. The surgery abolishes exercise-induced abnormalities, enhancing ejection fraction during physical activity.
Area of Science:
- Cardiology
- Cardiac Surgery
- Nuclear Cardiology
Background:
- Chronic stable angina pectoris often involves impaired left ventricular function during exercise.
- Myocardial revascularization aims to restore cardiac function and improve symptoms.
Purpose of the Study:
- To evaluate the impact of coronary artery bypass grafting (CABG) on global and regional left ventricular (LV) function.
- To assess changes in LV ejection fraction and wall motion at rest and during exercise post-CABG.
Main Methods:
- Multiple gated ventricular scintigraphy (MUGA) was performed at rest and during supine exercise.
- 56 patients with chronic stable angina pectoris were studied before and six weeks after CABG.
- Analysis included global left ventricular ejection fraction and regional wall motion scores.
Main Results:
- Before CABG, exercise induced a significant decline in ejection fraction and regional wall motion.
- Six weeks post-CABG, 52 patients were symptomless; resting LV function remained unchanged.
- During exercise post-CABG, ejection fraction significantly increased, and exercise-induced wall motion abnormalities were abolished.
Conclusions:
- Coronary artery bypass grafting effectively abolishes exercise-induced left ventricular functional abnormalities in patients with ischemic heart disease.
- MUGA is a safe, objective, and reproducible method for assessing serial ventricular function.
- CABG improves exercise capacity and LV performance but does not alter resting LV function.
Abstract:
The effect of coronary artery bypass grafting on global left ventricular ejection fraction and regional contraction was studied in 56 consecutive patients with chronic stable angina pectoris by means of multiple gated ventricular scintigraphy at rest and during dynamic supine exercise before and six weeks after myocardial revascularisation. Before operation, exercise induced a significant fall in ejection fraction and regional wall motion score. Six weeks after operation 52 patients were symptomless. Resting ejection fraction and regional wall motion score were unchanged but during exercise ejection fraction increased significantly, and the previous exercise induced regional wall motion abnormalities were abolished. All four patients with persisting angina showed the same pattern as before operation, with a fall in left ventricular ejection fraction and regional wall motion score during exercise. Multiple gated ventricular scintigraphy affords a safe, objective, reproducible, and non-invasive means of assessing serial ventricular function at rest and during exercise in patients with ischaemic heart disease. The technique confirms that coronary bypass surgery abolishes exercise induced abnormalities of left ventricular function, but has no influence on resting function.