From the Guidelines
Septal myectomy is a highly effective surgical procedure for patients with hypertrophic cardiomyopathy (HCM) who have significant left ventricular outflow tract (LVOT) obstruction and remain symptomatic despite optimal medical therapy, with a mortality rate of less than 1% and clinical success rate of over 90% to 95% 1.
Indications for Septal Myectomy
The main indications for septal myectomy include:
- Persistent symptoms such as dyspnea, chest pain, syncope, or near-syncope despite maximum tolerated doses of beta-blockers, calcium channel blockers, or disopyramide
- LVOT gradient ≥50 mmHg at rest or with provocation
- Significant left ventricular outflow tract obstruction
Pre-Procedure Workup
The workup for septal myectomy typically involves a comprehensive cardiac evaluation, including:
- Echocardiography to assess septal thickness and LVOT gradient
- Cardiac MRI to evaluate myocardial fibrosis and precise anatomy
- Cardiac catheterization to measure hemodynamics
- Exercise testing to assess functional capacity
Procedure
The procedure involves a median sternotomy approach under cardiopulmonary bypass, where the surgeon removes a portion of the thickened interventricular septum through an aortotomy, typically resecting 3-10 mm of muscle from the basal septum extending from below the aortic valve to beyond the mitral valve contact point 1.
Post-Procedure Care
Postoperatively, patients require:
- Close monitoring in the ICU
- Gradual activity progression
- Follow-up echocardiography to assess the reduction in LVOT gradient
Outcomes
Most patients experience significant symptom improvement with over 90% showing sustained relief and reduced risk of sudden cardiac death, and long-term survival after surgical myectomy is similar to an age-matched general population 1.
From the Research
Indications for Septal Myectomy
- Septal myectomy is indicated for patients with hypertrophic obstructive cardiomyopathy (HOCM) who have symptoms such as chest pain, shortness of breath, and fainting spells despite optimal medical therapy 2, 3.
- Patients with significant left ventricular outflow tract obstruction, as evidenced by echocardiography and cardiac catheterization, are also candidates for septal myectomy 2, 4.
- Septal myectomy can be considered for patients who have failed other treatments, such as dual-chamber pacemaker implantation or percutaneous transluminal septal myocardial ablation 2, 5.
Procedure for Septal Myectomy
- Septal myectomy involves the surgical removal of a portion of the thickened septal wall to relieve left ventricular outflow tract obstruction 2, 3.
- The procedure can be performed using a Morrow myectomy or a modified Konno procedure 2.
- The goal of the procedure is to reduce the thickness of the septal wall and relieve the obstruction, thereby improving symptoms and reducing the risk of sudden cardiac death 3, 4.
Comparison with Other Treatments
- Septal myectomy has been compared to other treatments, such as endocardial radiofrequency ablation and alcohol septal ablation, in terms of efficacy and safety 5, 6.
- Studies have shown that septal myectomy is superior to endocardial radiofrequency ablation in reducing left ventricular outflow tract gradients and improving symptoms 5.
- However, septal myectomy is a more invasive procedure than alcohol septal ablation, and the choice of treatment depends on individual patient factors and preferences 4, 6.
Outcomes and Complications
- Septal myectomy has been shown to be effective in reducing symptoms and improving quality of life in patients with HOCM 2, 3.
- The procedure is generally safe, with low operative mortality rates (approximately 1%) and few complications 2, 3.
- However, septal myectomy can be associated with complications, such as conduction system abnormalities and septal patch suture leaks 2, 6.