By Rachel Hagan A devastated mum who found her “fit and healthy” son dead on his bedroom floor is desperate for every teen in the country to be screened for heart conditions. Sam Richards’ son Toby was keeping up a strict fitness regime in preparation for joining the Royal Marines but had an undetected irregular heartbeat when he died in 2019 from sudden arrhythmic death syndrome (SADS). Around 500 Brits every year die from the syndrome, according to the British Heart Foundation. The diagnosis is made when someone dies unexpectedly from a cardiac arrest but the root cause of the medical event …