Exercise Body Surface Potential Mapping in Single and Multiple Coronary Artery Disease: Methods (Part 6)
Analog images were interpreted from x-ray transparent film without computer enhancement or background subtraction, independent of other clinical and study data. Exercise and 4-h redistribution scans were analyzed in pairs for the presence or absence of a thallium defect. Exercise defects were classified as fixed (unchanged at redistribution) or reversible (reduced or absent at redistribution). Reversible defects were considered positive scintigraphic evidence of exercise-induced ischemia. Scans were further classified in a semiquantitative manner, according to the method of Atwood et al. Defect size was graded on a scale of 1 to 5, with 10^20 percent of myocardial area scored as 1; 20^30 percent, 2; 30<40 percent, 3; 40^50 percent, 4; and, >50 percent, scored as 5. Defect intensity was graded as follows: 1 = normal uptake; 2= just less than normal; 3=just greater than background; and 4 = equivalent to background activity. Size and intensity scores from all three views were summed at both exercise and 4-h redistribution. Patients with reversible defects then had a net severity score calculated as the exercise score minus the redistribution score. This net score was utilized as a quantitative reflection of exercise-induced perfusion deficit and myocardial ischemia (Table 2). buy asthma inhalers
Conmary Angiography In addition to standard clinical evaluation of percent luminal narrowing (Table 1), the coronary arteriograms of all study patients were assessed according to the Pujadas, Green lane and modified Gensini scoring systems. Our modification of the Gensini system was designed to allow for the presence of effective collaterals.