A simple surgical technique during cardiac surgery was associated with a 56 percent reduction in the incidence of an irregular heart rhythm known as atrial fibrillation that can lead to stroke, with no added risks or side effects, according to a new study. The findings suggest that the method, called posterior left pericardiotomy, has significant potential for preventing prolonged hospital stays and the need for additional interventions and drugs to reduce the risk of strokes and heart failure associated with atrial fibrillation.