[7] In unstable angina, symptoms related to decreased blood flow to the heart may appear on rest or on minimal exertion.

[7][8] The cardinal symptom of critically decreased blood flow to the heart is chest pain, experienced as tightness, pressure, or burning.

[5] Localisation is most commonly around or over the chest and may radiate or be located to the arm, shoulder, neck, back, upper abdomen, or jaw.

[12] Unstable angina is characterized by at least one of the following: Fifty percent of people with unstable angina will have evidence of necrosis of the heart's muscular cells based on elevated cardiac serum markers such as creatine kinase isoenzyme (CK)-MB and troponin T or troponin I, and thus have a diagnosis of non-ST elevation myocardial infarction.

[17][18] In addition, nitroglycerin causes peripheral venous and artery dilation reducing cardiac preload and afterload.