Representative macroscopic cardiac sections with 2,3,5‐triphenyltetrazolium chloride (TTC) staining (A) and its quantification data (B), cardiac functional parameters heart rate (C), left ventricular pressure (LVP) (D), rate of rise in left ventricular pressure (+dP/dt) (E) and rate of decline in left ventricular pressure (–dP/dt) (F), and quantification data of perfusion pressure (G) were shown in ALDH2*2 diabetic mice with 1‐day Vehicle (Vehicle) or Alda‐1 (Alda‐1) pretreatment, and hereafter sham operation (Sham) or ischemia reperfusion injury (IRI). Representative micrographs of double staining of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and CD31 immunofluorescence staining and the merging of both staining in CECs of cardiac sections (H through P) and the quantification data of staining of CD31 (Q) and TUNEL (R) in ALDH2*2 diabetic mice with Sham, or pretreated with Vehicle or Alda‐1 before IRI. Data are presented as mean±SEM. *P<0.05, **P<0.01, and ***P<0.001. N=6. ALDH2 indicates aldehyde dehydrogenase 2; ALDH2*2, ALDH2 mutant allele; CEC, coronary endothelial cell; and WT, wild type.