As soon as Tyrion is reduced co 1 Wound he gets a 2+ Ward save for the rest of the battle (including after the Heart has restored him, should this happen). This will replace the 4+ Ward save from the Dragon Armour of Aenarion as you can't have more than one Ward save. Note that if an attack will inflict multiple wounds, for example a cannon ball, then Tyrion will only get this special Ward save if he has already been reduced to 1 Wound before he is hit.
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