237SJ..........in the majority of heart attacks, the heart does continue to pump effectively, this being due to other coronary arteries opening up to maintain the blood supply to the heart muscle.
One MAY get cyanosis in the case of a heart attack if the heart is already "knackered" by previous heart attacks or valvular disease. Cyanosis takes time to develop and the heart or lungs must be failing for this to be clinically apparent.
Of course a massive coronary occlusion incompatible with life may show cyanosis prior to death.
The vast majority of survivable coronary occlusions do not show signs of hypoxia, one good reason being that they tend to be diagnosed and treated early.
Diagnosis of a heart attack is made on history, abnormal level of cardiac enzymes in the blood and at a later stage ECG changes.
Cyanosis (hypoxia) as a diagnostic tool is of minor significance.