Hypotensive response during dobutamine stress echocardiography in coronary patients: A common event of well-functioning left ventricle

Background: Hypotensive response during dobutamine stress echocardiography (DSE) is a common complication, lacking the prognostic significance of hypotension during exercise treadmill test. Hypothesis: The present study aimed to assess the possible mechanisms of hypotensive response during DSE and to compare it with exercise treadmill test. Methods: In all, 91 patients with known coronary artery disease (CAD) underwent both DSE and exercise treadmill test. Dobutamine-induced hypotension was defined as a systolic blood pressure drop greater than or equal to 20 mmHg from baseline or from the previous level of infusion. Results: Twenty-one (23%) patients, 10 of whom also had bradycardia, developed hypotension during dobutamine infusion. Five (5.5%) patients were severely symptomatic and the infusion was stopped prematurely, while in the remaining 16 the addition of atropine allowed the continuation of the test. Patients prone to hypotension were predominantly female (p = 0.0004), had smaller (p = 0.01) and better functioning left ventricles (p = 0.0004), were unlikely to have rest wall motion abnormalities (p = 0.0008) or multivessel CAD (p = 0.02), and had less ischemia (wall motion score difference) (p = 0.03), Hypotension during exercise treadmill test was observed in only one (1%)patient with left main disease. Conclusions: Hypotension during DSE is unrelated to the anatomical or functional extent of CAD and is frequent in the setting of a well-functioning left ventricle, We suppose that vigorous contraction of a small chamber during dobutamine infusion results in an excessive stimulation of cardiac mechanoreceptors that mediate reflex hypotension and bradycardia.