Traditionally the patient should be supine and well supported in the bed. No pillows unless documented and permitted by your facility. However, many patients, especially cardiac patients may have a very hard time lying supine.
Any time you have to change the position of the patient or use additional supportive measures (pillow under the knees or head), it is important that this be documented.
Changing the physical position may be enough to influence the shape of the cardiac complexes and make it more difficult for the physician to interpret and diagnose the patient. So, any changes must always be documented.
If there are metal side rails on the bed or gurney and it is necessary to raise them to stabilize the patient on the bed or for safety. Always make certain that there is a barrier (sheet, blanket, pillows or rail pad) between the patient and the rail.