Final answer:
Angina is a condition characterized by chest pain or pressure that occurs when heart muscle cells do not receive adequate blood flow and become starved of oxygen. It can be a symptom of coronary heart disease and is often classified as stable or unstable angina. In cases of angina, abnormal stress test results can occur even if the coronary arteries appear normal.
Step-by-step explanation:
Angina is a condition characterized by chest pain or pressure that occurs when heart muscle cells do not receive adequate blood flow and become starved of oxygen. It is often a symptom of coronary heart disease, which is caused by the buildup of plaque in the coronary arteries.
There are two types of angina: stable angina, which is brought on by physical exertion and improves with rest, and unstable angina, which occurs at rest, lasts longer, and may indicate an impending heart attack. In cases of angina, the stress of physical activity or emotional stress can cause abnormal stress test results, even when the coronary arteries appear normal on angiography.