"In the largest study of its kind, researchers found that having people pray for heart bypass surgery patients had no effect on their recovery. In fact, patients who knew they were being prayed for had a slightly higher rate of complications."
"The study looked for any complications within 30 days of the surgery. Results showed no effect of prayer on complication-free recovery. But 59 percent of the patients who knew they were being prayed for developed a complication, versus 52 percent of those who were told it was just a possibility."
CNN - Study: Prayer doesn't affect heart patients