Definition & Overview
Myectomy is the surgical procedure of treating hypertrophic cardiomyopathy. It involves removing a part of the septal wall that has thickened and resulted in limited blood flow coming from the left ventricle to the aorta.
Hypertrophic cardiomyopathy results from the enlargement of heart muscle cells, usually in the left ventricle. The limited blood flow causes the left ventricle to overwork itself. There are two types of hypertrophic cardiomyopathy; the obstructive type, which limits blood from flowing out of the left ventricle and the non-obstructive type, which may cause the blood to leak back into the mitral valve. Some people with this condition do not exhibit any symptoms, though most patients experience dizziness, chest pain, fainting, and shortness of breath.
Septal myectomy is considered a complex surgical procedure, often lasting for about 6 hours or more, especially if complications arise. It is an open-heart surgery carried out in a specialised medical facility.
Who Should Undergo and Expected Results
Patients diagnosed with obstructive hypertrophic cardiomyopathy are recommended to undergo myectomy particularly if they have already tried other treatment options for their condition but are unable to find relief and if they experience significant obstruction that severely limits the blood flow coming from the left ventricle to the aorta.
All patients being considered for myectomy are required to undergo detailed echocardiogram, cardiac catheterisation, and other routine tests for definitive diagnosis.
The procedure can be carried out on older patients but only if the determined risks outweigh the expected benefits.
Myectomy, which requires hospitalisation, has high survival rates, with patients experiencing immediate relief from obstruction and other associated symptoms. There are also reports of significant improvement in their quality of life following myectomy.
How is the Procedure Performed?
The patient is placed under general anaesthesia at the start of surgery. The surgeon makes a large incision in the chest area and separates the breastbone to access the heart. A thin tube, called a cannula, is inserted into the aorta and is threaded to the aortic valve. The use of cannula makes it unnecessary for the surgeon to make an incision in the heart itself. The pressure gradients between the aorta and the left ventricle is then measured. Visual imaging tools, such as an echocardiogram, are used to guide the surgeon while he performs the whole procedure. The heart function is temporarily suspended with the use of a heart-lung or bypass machine. The thickened muscles are then located and identified. With the use of specialised tools, the surgeon removes these muscle tissues that cause obstruction and limited blood flow.
After the thickened tissue is removed, the patient is taken off the bypass machine. The surgeon measures the pressure gradient again to check improvement of blood flow. Pacing wires and drain tubes are temporarily placed inside the chest area. The breastbone is rewired back in place, and the incision is closed with sutures.
Patients are placed in intensive care and monitoring immediately after the procedure and may be fitted with implantable cardioverter-defibrillator to avoid any heart rhythm abnormality. Most patients recover and are able to resume normal activities after two months. They are expected to maintain a healthy lifestyle after surgery to facilitate healing and avoid long-term complications. Participation in a suitable rehabilitation program is also expected, while strenuous physical activities are discouraged.
Possible Risks and Complications
As a major, complex surgical procedure, myectomy’s risks and possible complications include:
- Adverse reaction to anaesthesia during surgery
- Complete heart block, a condition that results when the impulse generated from the atrium does not reach the ventricles. This impairs the ability of the heart to pump blood properly. If left unattended, this could cause death through sudden cardiac arrest
- Development of hole in the septum between the ventricles
- Injury to nearby coronary structures, especially the aortic and mitral valves
- Heart-related problems like irregular heartbeats and recurring chest pain
In rare cases, the procedure fails to remove the thickened muscle tissue and recurrence of hypertrophic cardiomyopathy may happen. Patients may need to undergo another operation to address this condition.
Ommen S, Maron B, Olivotto I, Maron M, Cecchi F, Betocchi S, Gersh B, Ackerman M, McCully R, Dearani J, Schaff H, Danielson G, Tajik A, Nishimura R (2005). “Long-term effects of surgical septal myectomy on survival in patients with obstructive hypertrophic cardiomyopathy”. J Am Coll Cardiol 46 (3): 470–6.
Ralph-Edwards A, Woo A, McCrindle B, Shapero J, Schwartz L, Rakowski H, Wigle E, Williams W (2005). “Hypertrophic obstructive cardiomyopathy: comparison of outcomes after myectomy or alcohol ablation adjusted by propensity score”. J Thorac Cardiovasc Surg 129 (2): 351–8.