What is the Lack of blood supply to heart resulting in rapid uncoordinated shuddering muscle called?

The provided answer is 'Atrial fibrillation'. While this is a well-known condition relating to rapid and uncoordinated heartbeats due to issues with the heart's electrical signals, it is not fully accurate in the contest provided.

Lack of blood supply to the heart muscle, which is typically referred to as 'ischemia' or 'myocardial ischemia', can lead to a condition called 'myocardial infarction' (commonly known as a heart attack) This occurs when the blood flow decreases of stops for a significant amount of time, depriving the heart muscle of oxygen and nutrients.

Myocardial infarction can result in various outcomes, including rapid uncoordinated shuddering of the heart muscle, which is accurately referred to as 'ventricular fibrillation'. Atrial fibrillation, on the other hand, while sharing similarities in the term, involves disruptions in the heart's electrical signals primarily in the atria (the upper chambers of the heart).