There was no significant difference in the infarct size between RTN3fl/fl and RTN3CKO mice 24 h after MI (Figure 2G); however, compared with AAV9‐Ctrl mice subjected to MI, RTN3 deficiency noticeably alleviated cardiac dysfunction and LV dilatation at 28 days post‐MI (Figure 2H). This evidence concerns the gene RTN3 and myocardial infarction.