attacks deal bonus damage, active deals additional damage to enemies
reduces shields of enemies
grants shield, boosts physical damage
armor penetration + sustain
at max stacks 12% increased damage
next basic attack strikes critically and heals you
under 30% of health gain shield, receive bonus damage based on 50% base AD

active deals bonus damage on the next attack

reduces attack speed of enemies, reduces physical damage. its very similar and cheaper option from Randuin's Omen, the only difference is Frozen Heart is used against aa champs when Randuin's Omen against critical champs like MF or Caitlyn
reduces critical damage, active slows enemies around. More expensive item than Frozen Heart but if you have enemy team comp that deals hard critical damage its very useful
reduces physical and magic damage which stores and transforms into true damage, heals if enemy dies within 3 secs
reduces healing, deals magic damage to attacking enemies. as an item with both armor and health stats its very good option for champs that scale either with HP or resistance

increases healing and shielding, also health regeneration so its very good for champs like Dr. Mundo, Volibear or Warwick
out of fight for 15 secs gain magical shield. this item is very good e.g. for galio as it has really good health stats and the magic shield empowers his passive shield as well. It is also very good m ritem for any other champion of course
vs ap burst, below 30% of health gain magic shield, triggering lifeline gains you lifesteal in fight

vs lots of cc, reduces magic damage
reduces attack damage