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.
- myocardial stunning
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