Does beta blocker therapy affect the diagnostic accuracy of adenosine single-photon-emission computed tomographic...

We retrospectively evaluated perfusion defect presence, extent, and severity in 158 consecutive patients receiving beta blockers, who underwent adenosine single-photon-emission computed tomography (SPECT) myocardial perfusion imaging (MPI) and coronary angiography. Seventy-six patients (group 1) had their beta blockers withdrawn 48 hours prior to testing, and 82 patients (group 2) remained on the beta blocker regimen. Groups 1 and 2 were similar in gender, age, pretest symptoms, and history of coronary artery disease (CAD). Group 1 patients had higher resting heart rates (79 +/- 19/min versus 68 +/- 13/min; P < 0.001), peak heart rates (91 +/- 21/min versus 80 +/- 15/min; P < 0.001), resting diastolic blood pressures (82 +/- 14 mm Hg versus 74 +/- 13 mm Hg; P < 0.001), peak systolic blood pressures (139 +/- 23 mm Hg versus 124 +/- 23 mm Hg; P < 0.001), and peak diastolic blood pressures (72 +/- 12 mm Hg versus 68 +/- 11 mm Hg; P = 0.04) than group 2 patients. Group 1 also had a higher incidence of angina during the 48 hours off beta blockers than group 2 (10% versus 2%; P < 0.001). There was no significant difference between the two groups in symptoms and side effects during adenosine infusion, quantitated lung/heart ratio, visually assessed lung uptake, transient ischemic dilation, post-stress ejection fraction, summed stress score, summed rest score, and summed difference score. In conclusion, in patients with CAD, beta blocker therapy does not affect the extent, severity, and reversibility of perfusion defects on adenosine SPECT MPI.