Study on the regional systolic bulging in patients with previous myocardial infarction

Regional systolic bulging during early systole has been reported to be present frequently in regions with ischmic or scarred myocardium. To sturdy the mechanisms of the systolic bulging and effects of isosorbide dinitrate (ISDN) and nifedipine on the systolic bulging, we conducted resting gated radionuclide venticulographic study (RIVG) and Tl-201 myocardial scintigram in 35 patients with old anteroseptal myocardial infarction (ASMI), 16 and 10 patients of them also underwent RIGV after ISDN or after nifedipine , respectively. A computer program subdivided the image of the LV into 4 regions, and the time-activity curves in the global LV, septal, and lateral regions were used for analysis. The degree of the systolic bulging (%Bulging) was calculated as follows : %Bulging＝ [(maximal－LV－C)(ED－LV－C)] / [(ED－LV－C)(ES－LV－C)] ＊ 100] LV－C