Which type of angina occurs due to vasospasms of the coronary arteries, often during sleep?

Prinzmetal angina, also known as variant angina, is characterized by episodes of chest pain that occur due to vasospasms of the coronary arteries. These spasms can happen at rest and are often more prevalent during sleep or early morning. This type of angina is distinct in that it is not necessarily triggered by physical exertion or stress, which differentiates it from other forms of angina.

The key features of Prinzmetal angina include its unpredictable nature and the fact that it can often lead to transient ischemic changes visible on an electrocardiogram (ECG) during episodes. The pain generally resolves with rest or the use of nitroglycerin, which helps to alleviate the spasms.

The other types of angina do not have the same causative mechanism or patterns. Unstable angina is characterized by increased frequency and severity, often occurring at rest and not relieved by usual measures. Stable angina, on the other hand, occurs predictably with exertion and is relieved with rest or medication. Silent angina often presents without noticeable symptoms, making it less likely to cause acute pain sensations. Understanding the nature and causes of different types of angina is vital for appropriate diagnosis and management.