"There is increasing evidence that this (PFO) is a significant issue. In a study at Duck University, the hearts of 30 divers who suffered from DCI were examined by two-dimensional electrocardiography. Eleven of these divers were found to have a patent Foramen Ovale. These 11 divers were amoung the 18 divers who had the more serious, neurological symptoms of decompression illness. A British study detected shunts in 15 of 63 (24%) of control divers with no history of DCI, 41% of 61 divers who had suffered DCI, and 66% of 19 patients who had suffered early onset neurological DCI. More recently, the same research group demonstrated a medium to large PFO in 52% of 100 divers with neurological DCI compared to 12.2% of divers controls who had not suffered DCI. These data strongly suggests that patent foramen ovale, especially a large PFO, may impose a greater risk of serious neurological DCI."