Background: Experimental studies demonstrate cardiac lipotoxicity as a potential mechanism of ''diabetic cardiomyopathy''. Studies on left ventricular [LV] function in patients with type II diabetes mellitus[DM] are complicated by concomitant myocardial ischemia/infarction due to CAD and microvascular disease. A recent report suggested that patients with early DM exhibit a normal myocardial response to Dobutamine.Materials and methods: This study examined LV ejection fraction[EF] and volumes in a consecutive group of men and women with type II DM and compared the results to those without DM. All patients had normal stress and rest SPECT Tc-99m Tetrofosmin images. The EF, end-diastolic volume[EDV], end-systolic volume [ESV], and LV mass [LVM] were measured by gated SPECT.Results: The EF, EDV, EDV-index[EDVI], ESV, ESV-index[ESVI] and LVM were comparable in men and women with or without DM[table]. Group1= Men with DM, Group 2= Men without DM, Group 3= Women with DM, Group 4 =Women without DM GroupAge [yr]EF [%]EDV [ml]EDVIESV [ml]ESVILVM [gm]Group 1 [n = 30]52 +/- 1054 +/- 10104 +/- 2851 +/- 1346 +/- 2223 +/- 11155 +/- 22Group 2 [n = 78]50 +/- 1357 +/- 8102 +/- 3151 +/- 1643 +/- 1922 +/- 10150 +/- 24Group 3 [n = 40]58 +/- 1563 +/- 1082 +/- 2741 +/- 1431 +/- 2015 +/- 10134 +/- 22Group 4 [n = 90]53 +/- 1367 +/- 1074 +/- 2339 +/- 1526 +/- 1614 +/- 10131 +/- 24*p < 0.001 vs Group 1, p < 0.001 vs Group 2Conclusion: The LV EF and volumes are comparable in patients with and without type II DM in the absence of ischemia or infarction. The LV volumes and EF are lower in women than men in the presence or absence of DM. It is possible that ischemia/infarction affect more adversely the LV function in DM accounting for the worse LV function [and worse outcome] in patients with established CAD.