Isn't a heart attack basically the heart muscle getting too fatigued to keep going? It doesn't seem to ben the only muscle that doesn't get tired - e.g. if it

Isn't a heart attack basically the heart muscle getting too fatigued to keep going? It doesn't seem to ben the only muscle that doesn't get tired - e.g. if it weren't for sleeping I suspect the neck muscles could hold up the head indefinitely. The diaphragm obviously never gets tired either, unless you have asthma. I can also type pretty much indefinitely without feeling muscle fatigue in my fingers. climbing on the other hand will exert them enough to quickly fatigue them.