This condition differs from other
types of angina. Other types of angina commonly occur when the person is active. They
also tend to occur in people with coronary artery disease (CAD). With CAD, arteries
the heart have a buildup of a fatty substance called plaque. The plaque narrows the
coronary arteries and reduces blood flow to the heart muscle, which causes angina.
Angina with CAD is often brought on by an increased workload on the heart muscle,
as during exercise. In contrast, coronary artery spasm most often occurs during rest.
fact, it often occurs at night during sleep, often between midnight and early