A connecting heart was a large construct of incredibly powerful magic, possessing life magic deep within them. Generally composed of a hard shell such as crystal or stone, powerful connective lines linked the "heart" of the construct with its creator. Provided they were on the same plane, the heart would provide life energy to its caster. Typically, this triggered automatically whenever the caster was injured, though some connecting hearts were only programmed to be have energy accessible on request.
Depending on their source of energy, some connecting hearts pulsed with the thrums of life, causing the structure itself to "beat". They generally were large, with a radius of twenty feet, and could sustain a fair amount of damage before the core of the heart failed. If not destroyed, the life energy from the heart's core would slowly regenerate the construct.