The Heart Sūtra is made up of 14 shlokas in Sanskrit. In Chinese, it is composed of 260 Chinese characters. In English, it is composed of sixteen sentences.
The Heart Sūtra, it is generally thought, is likely to have been composed in the 1st century CE in Kushan Empire territory, by a Sarvastivadin or ex-Sarvastivadin monk.
The earliest record of a copy of the sūtra is a 200-250CE Chinese version attributed to the Yuezhi monk Zhi Qian. It was supposedly translated again by Kumarajiva around 400CE, although John McRae and Jan Nattier have argued that this translation was created by someone else, much later, based on Kumarajiva's Large Sūtra.
Zhi Qian's version, if it ever existed, was lost before the time of Xuanzang, who produced his own version in 649CE, which closely matches the one attributed to Kumarajiva. Xuanzang's version is the first record of the title "Heart Sūtra" (心經 xīnjīng) being used for the text, and Fukui Fumimasa has argued that xinjing actually means dharani scripture. According to Huili's biography, Xuanzang learned the sutra from an inhabitant of Sichuan, and subsequently chanted it during times of danger in his journey to the West.
data source: http://en.wikipedia.org/wiki/Heart_Sutra