Some cardiac arrests may be all in the mind. Researchers in Canada have discovered a region in the brain that controls the activity of heart and blood vessels. According to them, abnormalities in the region can result in heart attacks. They suspect that many unexplained heart attacks could be due to malfunctioning of the brain's cardiovascular control centre. The unexplained heart attacks include nearly six per cent of all heart patients who do not have the history of heart problems. The researchers speculate that the attacks arise as their strokes may have damaged the brain's cardiovascular site ( New Scientist , Vol 156, No 2107).