A solution comprises a preservation mixture comprising a calcium ion source； and a buffer for maintaining a pH of the solution. The molar concentration of calcium ion (Ca2+) in the solution is from 0.18 to 0.26 mmol/L, and the pH is lower than 7.4 and higher than 6.6. A composition for preparing the solution may comprise adenosine, lidocaine, and a calcium source, wherein the molar ratio of adenosine:calcium is from 0.3:0.26 to 0.45:0.18, and the molar ratio of lidocaine:calcium is from 0.04:0.26 to 0.09:0.18. A donor heart may be reperfused with the solution. The solution may be used for reperfusion of a donor heart, such as at a temperature from about 25 to about 37° C. The donor may be a donor after circulatory death.
