After the patient is asleep, a device called the Swan-Ganz catheter is often inserted through a needle stick into the jugular vein (in the neck) and threaded to the pulmonary artery, which goes from the heart to the lungs. The catheter can be used to measure heart function, measure the pressures in both the heart and lungs, and give any necessary medications. A urinary catheter is also inserted and connected to a collection bag to measure the patient’s urine output.

An 11- to 12-centimeter incision (about 4-1/2 inches) is then made in the chest, through the breastbone (sternum), and the two halves of the breastbone are divided (a full median sternotomy). A retractor is used to gently pull back the two halves of the breastbone to give the surgeon plenty of room to work.

The functions of the heart, including blood flow and oxygenation, are rerouted through a heart-lung machine via tubes (cannulas) that are placed in the body. While this machine takes care of the heart’s functions, the heart can be carefully stopped with a cardioplegic solution so the surgeon can perform his or her very delicate work. Some surgeons may further protect the heart by decreasing its temperature. The heart will remain stopped for about 30 to 90 minutes during the two to four hours (on average) of surgery.

Based on the results of the transesophageal echocardiogram, the surgeon knows where and how much of the overgrown muscle cells need to be removed. The surgeon makes an incision in the aorta through which the the surgeon can access the heart and remove excess septal muscle. Once the procedure is completed, the incision in the aorta is closed and the heart is restarted. When the surgical team is satisfied that the heart is beating strongly again, the heart-lung machine will be removed. The chest incisions are then closed (sutured).

Blood transfusion may be needed during any type of open-heart surgery, including a septal myomectomy. The patient or family members may donate blood prior to the surgery. If blood is used from a  blood bank, it has been tested to make sure it is free from any diseases, such as hepatitis or human immunodeficiency virus (HIV).