Prolonged left ventricular dysfunction occurs in patients with coronary artery disease after both dobutamine and exercise induced myocardial ischaemia

Objective-To determine whether pharmacological stress leads to prolonged bu t 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 diasto lic left ventricular function after exercise and dobutamine induced ischaem ia. Subjects-10 patients with stable angina, angiographically proven coronary a rtery disease, and normal left ventricular function. Interventions-Treadmill exercise and dobutamine stress were performed on di fferent days. Quantitative assessment of systolic and diastolic left ventri cular function was performed using transthoracic echocardiography at baseli ne and at regular intervals after each test. Results-Both forms of stress led to prolonged but reversible systolic and d iastolic 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 e xercise, ejection fraction was reduced at 15 and 30 minutes compared with b aseline (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 segme nt 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 iso volumic relaxation period was prolonged 45 minutes after each form of stres s (p < 0.05). Conclusions-In patients with coronary artery disease, dobutamine induced is chaemia results in prolonged reversible left ventricular dysfunction, presu med to be myocardial stunning, similar to that seen after exercise. Dobutam ine induced ischaemia could therefore be used to study the pathophysiology of this phenomenon further in patients with coronary artery disease.