A stress test can identify coronary arteries where at least 70 percent of the vessel is blocked. While stress tests have high accuracy rates (80 to 85 percent), they often cannot detect smaller blockages, especially those due to atherosclerosis, a condition where a combination of fat, calcium and cholesterol traveling through the bloodstream forms plaque buildups on artery walls.
Because stress tests and other detection methods cannot always detect smaller blockages, there is a small chance that a person who has received a normal result on a stress test could still suffer a heart attack. Statistics show that less than 1 percent of people with normal stress test results will experience heart attacks in the next year.
