noun Date: 1972 angina pectoris characterized by sudden changes (as an increase in the severity or length of anginal attacks or a decrease in the exertion required to precipitate an attack) especially when symptoms were previously stable
UNSTABLE ANGINA
Meaning of UNSTABLE ANGINA in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012