What is the most likely diagnosis for a 66-year-old male experiencing intermittent episodes of chest pressure that resolve spontaneously?

The scenario presented—intermittent episodes of chest pressure that resolve spontaneously—is most consistent with stable angina. Stable angina typically occurs with exertion or stress and is relieved with rest or the use of nitroglycerin. The key feature here is the transient nature of the chest pressure, which indicates a predictable pattern associated with exertion rather than a more urgent condition.

Unstable angina, in contrast, is characterized by episodes of chest pain that increase in frequency, duration, or intensity, which do not resolve with rest or are unpredictable. This patient's symptoms resolving spontaneously and not indicating a pattern of increasing discomfort aligns more closely with stable angina rather than unstable angina, which would suggest a higher risk of imminent myocardial infarction.

Pericarditis usually presents with sharp chest pain that can worsen with deep breathing or lying down and is often accompanied by other symptoms or physical findings (like a pericardial rub), which is not described in this case. On the other hand, a STEMI (ST-Elevation Myocardial Infarction) typically presents with more severe, persistent chest pain that does not resolve spontaneously and requires immediate medical intervention.

Thus, the characteristics of the chest episodes—specifically their intermittency and resolution—