UNLABELLED: Changes of regional myocardial perfusion before and after administration of Atenolol (AT) (5 mg i.v.) were investigated by 201-Tl stress-imaging in 14 patients (PAT) with greater than or equal to 70% coronary obstructions. Scintigrams were performed in 4 projections (AP, 30 degree LAO, 60 degrees LAO, left lateral); scintigraphic defects (SD) in one of the 6 LV segments (anterior, apical, inferior, septal, lateral, posterior) had to be identified in at least 2 projections and to show a decrease of activity greater than or equal to 25%. All PAT had at least one reversible SD. RESULTS: After AT, stress, induced SDs were unchanged in 11 of the 14 PAT at identical work loads (131 Watt). The total number of reversible defects was 33 before and 28 after AT (n.s.). However, not only the 3 PAT with improved stress scintigrams, but also 6 of the 11 PAT with unchanged abnormal stress scintigrams were clinically improved (ECG normalized, no angina). Thus in almost half of the patients (6/14), the stress ECG was normalized without normalization of perfusion pattern of thallium scintigrams. We conclude that in these patients subendocardial perfusion was enough improved to meet the reduced metabolic needs, but not enough to normalize stress images.
UNLABELLED: Changes of regional myocardial perfusion before and after administration of Atenolol (AT) (5 mg i.v.) were investigated by 201-Tl stress-imaging in 14 patients (PAT) with greater than or equal to 70% coronary obstructions. Scintigrams were performed in 4 projections (AP, 30 degree LAO, 60 degrees LAO, left lateral); scintigraphic defects (SD) in one of the 6 LV segments (anterior, apical, inferior, septal, lateral, posterior) had to be identified in at least 2 projections and to show a decrease of activity greater than or equal to 25%. All PAT had at least one reversible SD. RESULTS: After AT, stress, induced SDs were unchanged in 11 of the 14 PAT at identical work loads (131 Watt). The total number of reversible defects was 33 before and 28 after AT (n.s.). However, not only the 3 PAT with improved stress scintigrams, but also 6 of the 11 PAT with unchanged abnormal stress scintigrams were clinically improved (ECG normalized, no angina). Thus in almost half of the patients (6/14), the stress ECG was normalized without normalization of perfusion pattern of thallium scintigrams. We conclude that in these patients subendocardial perfusion was enough improved to meet the reduced metabolic needs, but not enough to normalize stress images.