A legal battle has been launched between restaurants in the US, over the rights to serving food with a heart attack theme.

Bosses from Heart Attack Grill say they have been forced to call in the lawyers after a rash of other restaurants copied their ideas.

The Arizona restaurant specialises in selling giant death-defying burgers - ranging from a single to a 'Quadruple Bypass' - in a medically themed setting.  

Diners are referred to as 'patients' and given 'prescriptions' rather than meals... though looking at those burgers it probably wouldn't hurt to have a real doctor on hand too.