The most common complications after heart surgery include atrial fibrillation, which occurs in nearly 1 in 3 patients; retained blood syndrome, which occurs in 1 in 4 patients; bloody pleural effusions, which occur in 1 in 10 patients; and infections, which occur in approximately 1 in 20 patients. Hospital readmissions often occur in cardiac surgery patients; in 2010, approximately 18.5% of patients who had a heart valve procedure in the United States were readmitted within 30 days of the initial hospitalization.[27] Readmissions are primarily related to the four most common complications, and recent efforts have focused on preventing problems like chest tube clogging that contribute to these complications.