Roughly 5 percent of patients laid low by strokes experience heart attacks soon afterward, sometimes without any prior known history of cardiac disease. Now researchers have found a region of the brain that, when damaged by a stroke, appears to cause a 15 times greater risk for ensuing heart muscle injury. Workers at Massachusetts General Hospital analyzed 50 patients with stroke caused by arterial blockage who also had elevated levels of enzymes released by damaged cardiac muscle. Magnetic resonance imaging scans pinpointed the right insular area as the culprit, a region deep inside the brain linked with the part of the nervous system that sets off stress-related responses. The findings could help prioritize stroke patients at risk of heart attacks for protective therapy. Future studies may also reveal which stroke patients are more likely to develop pneumonia or disruptions in heart rhythm. The research appears in the May 9 Neurology. This article was originally published with the title "From Brain to Heart" in Scientific American 295, 1, 32 (July 2006)