Apple's unannounced iWatch could be used to predict potential heart attacks, according to a report, Digital Spy said.

The wearable device will monitor the user's blood flow and alert them if medical attention is required, a purported inside source has told the San Francisco Chronicle.

THX and 10.2 surround sound inventor Tomlinson Holman, who joined Apple in 2011, is said to be heading up research into the potential health applications of the iWatch.

Apple previously sparked rumours that the product will feature a health and fitness focus when it hired medical tech specialists Nancy Dougherty and Ravi Narasimhan.

Meanwhile, recent reports have suggested that the iWatch could feature a display made of sapphire glass and include solar charging functionality.

Apple is yet to officially announce the product.