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Prolonged left ventricular dysfunction occurs in patients with coronary artery disease after both dobutamine and
E Barnes1, C S Baker, D P Dutka
1Department of Cardiology, Imperial College School of Medicine, Hammersmith Hospital, London W12 0NN, UK.
Insights
Pharmacological stress with dobutamine causes reversible left ventricular dysfunction in coronary artery disease patients, similar to exercise stress. This finding allows further study into myocardial stunning.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Pharmacology
Background:
- Coronary artery disease (CAD) can lead to left ventricular dysfunction.
- Exercise stress testing is used to assess cardiac function in CAD patients.
- The effects of pharmacological stress on left ventricular function recovery are less understood.
Purpose of the Study:
- To compare the effects of dobutamine-induced ischemia with exercise-induced ischemia on left ventricular function recovery in CAD patients.
- To determine if dobutamine stress mimics exercise stress in causing prolonged, reversible left ventricular dysfunction.
Main Methods:
- A randomized crossover study involving 10 patients with stable angina and CAD.
- Transthoracic echocardiography was used to quantitatively assess systolic and diastolic left ventricular function.
- Patients underwent both treadmill exercise and dobutamine stress tests on separate days, with function assessed at regular intervals post-stress.
Main Results:
- Both dobutamine and exercise stress induced prolonged, reversible systolic and diastolic left ventricular dysfunction.
- Ejection fraction and regional wall motion abnormalities were significantly reduced post-stress for both methods.
- The isovolumic relaxation period was prolonged similarly after both exercise and dobutamine stress.
Conclusions:
- Dobutamine-induced ischemia causes reversible left ventricular dysfunction in CAD patients, comparable to exercise-induced ischemia.
- This dysfunction is presumed to be myocardial stunning, similar to that observed after exercise.
- Dobutamine stress provides a viable model for further research into the pathophysiology of myocardial stunning in CAD.
Objective:
To determine whether pharmacological stress leads to prolonged but reversible left ventricular dysfunction in patients with coronary artery disease, similar to that seen after exercise.
Design:
A randomised crossover study of recovery time of systolic and diastolic left ventricular function after exercise and dobutamine induced ischaemia.
Subjects:
10 patients with stable angina, angiographically proven coronary artery disease, and normal left ventricular function.
Interventions:
Treadmill exercise and dobutamine stress were performed on different days. Quantitative assessment of systolic and diastolic left ventricular function was performed using transthoracic echocardiography at baseline and at regular intervals after each test.
Results:
Both forms of stress led to prolonged but reversible systolic and diastolic dysfunction. There was no difference in the maximum double product (p = 0.53) or ST depression (p = 0.63) with either form of stress. After exercise, ejection fraction was reduced at 15 and 30 minutes compared with baseline (mean (SEM), -5.6 (1.5)%, p < 0.05; and -6.1 (2.2)%, p < 0. 01), and at 30 and 45 minutes after dobutamine (-10.8 (1.8)% and -5. 5 (1.8)%, both p < 0.01). Regional analysis showed a reduction in the worst affected segment 15 and 30 minutes after exercise (-27.9 (7.2)% and -28.6 (5.7)%, both p < 0.01), and at 30 minutes after dobutamine (-32 (5.3)%, p < 0.01). The isovolumic relaxation period was prolonged 45 minutes after each form of stress (p < 0.05).
Conclusions:
In patients with coronary artery disease, dobutamine induced ischaemia results in prolonged reversible left ventricular dysfunction, presumed to be myocardial stunning, similar to that seen after exercise. Dobutamine induced ischaemia could therefore be used to study the pathophysiology of this phenomenon further in patients with coronary artery disease.