Chest pain is not a symptom you should ever ignore, for obvious reasons. Chest pain, as almost anyone knows, may indicate a cardiac problem. For this reason alone, if you have chest pain you should be evaluated by a doctor.
Definition of cardiac muscle. : the principal involuntary-muscle tissue of the vertebrate heart made up of striated fibers joined at usually branched ends and functioning in synchronized rhythmic contraction.
An isolated cardiac muscle cell, beating Cardiac muscle (heart muscle) is striated muscle (striped muscle) in the walls of the heart. It makes up the tissue called the myocardium. It is involuntary: a person cannot control it consciously. Cardiac muscle is one of three main types of muscle, the others being skeletal and smooth muscle. The cells that make up cardiac muscle have one (74%) or two (24.5%) nuclei. The myocardium forms a thick middle layer between the outer epicardium layer and the inner endocardium layer.