Comparison of myocardial blood flow during dobutamine-atropine infusion with that after dipyridamole administration in normal men

OBJECTIVES The present study was designed to compare the absolute myocardia l blood flow (MBF) after intravenous dipyridamole infusion with that during dobutamine-atropine administration in normal healthy male volunteers. BACKGROUND Both safety and usefulness of dobutamine-atropine stress in myoc ardial perfusion imaging have been reported. However, no information exists on whether the magnitude of hyperemia achieved with dipyridamole and dobut amine-atropine is comparable. METHODS Myocardial blood flow was measured with positron emission tomograph y and O-15-labeled water in 20 healthy young men (23 +/- 3 years) 1) at bas eline, 2) after dipyridamole infusion (0.56 mg/kg over 4 min), and 3) durin g dobutamine (40 mug/kg/min) and atropine (0.25 to 1.0 mg) infusion. RESULTS The MBF was significantly increased during dipyridamole infusion an d during dobutamine-atropine stress compared with at rest (4.33 +/- 1.23 an d 5.89 +/- 1.58 vs. 0.67 +/- 0.16 ml/min/g, respectively, p < 0.0001). More over, dobutamine-atropine infusion produced greater MBF compared with dipyr idamole (p = 0.0011), while coronary vascular resistance did not differ sig nificantly after dipyridamole administration and during dobutamine-atropine infusion (17.6 +/- 7.9 vs. 18.6 +/- 5.6 mm Hg/[ml/min/g], respectively). CONCLUSIONS Near maximal coronary vasodilatation caused by dipyridamole is attainable using dobutamine and atropine in young healthy volunteers. Dobut amine in conjunction with atropine is no less effective than dipyridamole i n producing myocardial hyperemia. (J Am Cell Cardiol 2001;37: 130-6) (C) 20 01 by the American College of Cardiology.