1 ICD-9-CM 751.7 is a billable medical code that can be used to indicate a diagnosis on a reimbursement claim, however, 751.7 should only be used for claims with a date of service on or before September 30, 2015. 2  For claims with a date of service on or after October 1, 2015, use an equivalent ICD-10-CM code (or codes).
The myocardium is located between the endocardium and the visceral layer of the serous membrane (epicardium) of the heart.
SR is the site of storage and release of calcium ions for contraction. Three types of cardiocytes are found in the myocardium. 1) Cells found at the junction of the great veins and the right atrium have the fastest intrinsic rhythm (this is the sinoatrial (SA) node or 'pacemaker' of the heart). These are the AUTORHYTHMIC CELLS and they spontaneously discharge about 100 times per minute.