NEW : Questioning of Mubarak over corruption charges has begun , military says . Egyptian state television reports Mubarak had a heart attack . Comment: Mubarak stepped down from power on February 11 .
NEW : Questioning of Mubarak over corruption charges has begun , military says . Egyptian state television reports Mubarak had a heart attack . Mubarak has had health problems in the recent past . Mubarak stepped down from power on February 11 .