45. word "heart" (hrd-, n.) is using the form hrdaya- (n.) in some cases:
 
Sg. Du. Pl.
Nom. hrdayam hrdaye hrdayani
Acc. hrdayam hrdaye hrdayani|hrndi
Ins. hrdayena|hrda hrdayabhyam|hrdbhyam hrdayaih|hrdbhih
Dat. hrdayai|hrde hrdayabhyam|hrdbhyam hrdayebhyah|hrdbhyah
Abl. hrdayat|hrdah hrdayabhyam|hrdbhyam hrdayebhyah|hrdbhyah
Gen. hrdayasya|hrdah hrdayayoh|hrdoh hrdayanam|hrdam
Loc. hrdaye|hrdi hrdayayoh|hrdoh hrdayesu|hrtsu
Voc. hrdayam hrdaye hrdayani