Elsevier

American Heart Journal

Volume 130, Issue 2, August 1995, Pages 248-253
American Heart Journal

Clinical investigation
Effect of β-adrenergic receptor blockade on the physiologic response to dobutamine stress echocardiography

https://doi.org/10.1016/0002-8703(95)90436-0Get rights and content

Abstract

Dobutamine is an effective pharmacologic stress agent because of its β-adrenergic receptor agonist properties. Theoretically, concurrent β-adrenergic receptor blockade might alter this effectiveness, but clinical experience has been variable. Before assessing the relative effectiveness and implications of dobutamine stress echocardiography (DSE) to detect myocardial ischemia in the presence of β-blockade the physiologic and hemodynamic effects of dobutamine with simultaneous β-blockade must be understood in a controlled setting. Therefore the purpose of this study was to determine if β-blocking agents alter the timing and magnitude of the physiologic response to graded doses of dobutamine during a standard DSE. Paired DSEs were performed in seven instrumented open-chest dogs with and without β-blockade (esmolol 500 μ/kg initial bolus and 100 μ/kg/min infusion). Heart rate, systolic pressure, proximal left anterior descending coronary artery flow, myocardial thickening, and percentage left ventricular area change (%AC) were monitored. The data for each parameter were fit to linear or exponential functions. With graded doses of dobutamine, the rate of increase in coronary flow was greater than that in %AC, which in turn was greater than that in heart rate (p < 0.05). With the addition of β-blockade, (1) despite attainment of a higher peak dobutamine dosage (14.6 ± 8.2 vs 38.6 ± 3.8 μ/kg/min; p < 0.005), the peak heart rate, coronary flow, and %AC were lower (p < 0.01); (2) the rates of increase in heart rate, flow, and %AC were blunted compared with pre-β-blockade responses (p < 0.05); and (3) the rates of increase in heart rate and flow were less than that in %AC (p = 0.03). Regardless of β-blockade, mean systolic blood pressure remained relatively unchanged from predobutamine levels. β-Blocking agents alter the magnitude and timing of the physiologic response during DSE in this canine model. By lowering the peak cardiac workload and inotropic response during DSE, β-blockade has the potential to influence the sensitivity of this test.

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    The use of atropine is especially recommended for patients using beta-blockers. These latter medications lower the chronotropic and inotropic response (and, thus, peak cardiac workload) during dobutamine stress (18,68,69) and, thus, have the potential to lower the sensitivity of the test (70,71). The effect of the number of diseased coronary arteries was assessed in nine studies (9,11,15–17,20,22,24,25) for a total of 311 patients.

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