Jenny Simpson reveals rare heart condition caused her collapse; she will not return to running

The briefing

World champion runner Jenny Simpson said a rare heart condition, Arrhythmogenic Right Ventricular Cardiomyopathy, caused the cardiac arrest that felled her at a June race in Raleigh, North Carolina. The 39-year-old said the diagnosis makes returning to running dangerous and that chapter has ended. Simpson was America's most successful women's 1,500-meter runner for about a decade, winning the world title in 2011 and Olympic bronze in Rio in 2016.