This is one of those cases where there are two hostas with the same name. One is registered and, therefore, the "official" version of H. 'Big Hearted' while the other is a non-registered plant and needs to be renamed to avoid further confusion.
 

Dr. Ralph (Herb) Benedict of Michigan originated this cultivar and registered it in 1983. It is the result of a cross between H. nakaiana x H. 'Zager's Giant' (aka 'Herbert'). This plant grows into a medium size hosta around 14 inches in height by about 45 inches wide. The heart shaped foliage is slightly rippled, has some corrugation and has bloom on the underside. Its medium lavender flowers bloom in July.

Similar cultivars include H. 'Brooke' and H. 'Heartleaf'.

According to The Hostapedia by Mark Zilis (2009), "...not the same as the Van Wade plant of the same name (huge mound of blue-green foliage). 'Big Hearted' makes a much smaller specimen and has more of a heart-shaped leaf."