Variable. Depending on which cv disease you mean: heart attack? Heart failure? Cardiac arrest? Etc. Very generally, heart disease causes one or more of the following: chest pain, shortness of breath, fluid retention, palpitations, dizziness, or loss of consciousness. (sorry but that's a general answer to a general question).
A general term. All diseases, including cardiovascular diseases, can be divided into acute (new) or chronic (on-going). A medical aphorism is "to treat acute problems acutely and chronic problems chronically". Think of the difference as a "sprint" vs a "marathon." urgent problems may require immediate attention, although not all acute cv disorders are serious.
Dangerous. The conception of actue cardiovascular disease is mostly a dangerous situation, such as unstable angina, acute myocardial infaction, hypertension crisis etc. It not handled in a timely manner, endanger life.
The relatively. Sudden onset of disorders related to the cardiovascular system.