(A) IR-induced mortality is greatly enhanced in mice lacking βCys93 (C93A = γβC93A and βC93A) versus control mice (C93 = γβC93). In panels A, C, and D, numbers within histograms specify absolute ratios for each observation (B) Representative angiography illustrating collateralized circulation of the LV free wall to supply the apex in a mutant βC93A mouse. Lower (left; ×6.7) and higher (right; ×15.8) magnification views are shown. (C) Collateralization supplying the LV is significantly more likely in γβC93A and βC93A versus γβC93 mice. *P < 0.0001 for γβC93 versus γβC93A and **P = 0.0043 for γβC93 versus βC93A, respectively, by Fisher’s exact test (2-sided). The difference in collateralization between γβC93A and βC93A mice was not significant (P > 0.05). (D) Mortality during 24 hours of IR is determined by the presence versus absence of collateral circulatory supply of the LV and is enhanced in γβC93A and βC93A versus γβC93 mice. *P < 0.0001 vs. collateral by Fisher’s exact test (2-sided). (E) Representative Evans blue/TTC-stained LV slices illustrating areas of recovery (red) and necrosis (white) in a γβC93 mouse (left) and in a γβC93A mouse (right). Scale bar: 2 mm. (F) In γβC93A versus γβC93 control mice surviving 24 hours after IR, the area of recovery (Rec/LV; LV, total LV area) is significantly diminished and the area of necrosis (AON/LV) and the ratio of area of necrosis/area at risk (AON/AAR) are significantly enhanced, and enhanced injury was evident in the absence of βC93 even when collateralization was present. (G) Echocardiography of surviving mice reveals that LV ejection fraction (EF) and fractional shortening (FS) are significantly diminished in γβC93A versus γβC93 control mice, and these differences were evident even when collateralization was present. (H) Thickening of the LV anterior and posterior walls in the absence of collateral blood supply is significantly diminished in γβC93A versus γβC93 mice. In F–H, n = 3–7 for mice with collateral blood supply and n = 3–9 for mice without collateral blood supply. *P < 0.05 vs. γβC93 by Student’s t test (2-tailed).