Alcohol Septal Ablation for Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic disorder characterized by abnormal thickening of the heart muscle (myocardium). Usually only one part of the heart is affected, resulting in impaired functioning of the heart.

Usually HCM is asymptomatic, but in some people, thickening of the heart muscle may produce symptoms such as high blood pressure, life-threatening arrhythmias, fainting, and shortness of breath with activity or rest. HCM is considered as the primary cause of sudden death in preadolescent and adolescent children.

Alcohol septal ablation (ASA) is a minimally invasive procedure that reduces the proportion of tissue blocking the blood flow due to thickening of the heart muscles. ASA involves the injection of pure alcohol into the target septal branch of the left anterior descending coronary artery.

ASA is considered as a therapeutic alternative to surgical myectomy for the treatment of LVOT (left ventricular outflow tract) obstruction. ASA is often the best choice for elderly patients and those having advanced medical conditions who cannot tolerate open surgery.

Procedure

The basic steps involved in alcohol septal ablation are as follows:

  • The procedure is performed in a cardiac catheterization laboratory.
  • The patient is administered a sedative for relaxation and pain relief.
  • The cardiac activity of the patient is monitored during and after the procedure through transesophageal echocardiography.
  • Electrodes are placed on the chest to monitor the heart rate during the procedure.
  • Tubes are inserted into the artery and vein in your groin, and a temporary pacemaker is passed through the venous system to the right ventricle of the heart.
  • A guide wire and balloon catheter are inserted through the tube and moved to your heart.
  • Position of the septal artery is identified by employing a dye test, and then a balloon catheter is inserted to that region.
  • The position of the balloon is confirmed by echocardiography and the balloon is inflated to temporarily block the septal artery.
  • Alcohol (2-5 cc) is injected, causing the muscle cells in that area to shrink or die.
  • Finally, the balloon is deflated and removed from the septal artery.

If there is a disturbance in the electrical activity of the heart, the temporary pacemaker is adjusted. If there is no such problem, the temporary pacemaker is removed within 24 hours.

Post-operative care

Generally, this procedure requires 3-5 days of stay at the hospital. The basic post-operative instructions are as follows:

  • After the procedure, the patient is taken to the coronary care unit (CCU) and is kept under observation for the next 24 hours.
  • The tubes will be kept in the groin. They are removed when found suitable by the doctor.
  • Take the prescribed medication regularly.
  • Do not drive or perform any heavy work for at least 1 week after the procedure.
  • Consult your doctor in case of any bleeding, dizziness, pounding heart, and chest pain.

Limitations of alcohol septal ablation

Alcohol septal ablation is a very safe and effective procedure. Some limitations and side effects of ASA are as follows:

  • Lack of accuracy in targeting the specified area can cause obstruction
  • Lack of ability to handle additional cardiac lesions
  • May cause right bundle-branch block
  • May produce complete heart block (that requires permanent pacemaker)
  • Serious ventricular arrhythmias

Condition

Hypertrophic cardiomyopathy is a condition where your heart muscle is excessively thickened. It can cause severe shortness of breath, mitral regurgitation, chest pain, fainting spells, and cardiac arrhythmias. You may require medications, surgery, pacemakers, or defibrillators. There are multiple patterns of heart-muscle thickening that are diagnosed by echocardiography. Excessive thickening of the muscle in the septal area of the heart can lead to inadequate emptying of the heart and leaking of the mitral valve (mitral regurgitation). There is a growing body of evidence that indicates that reducing the thickness of the wall by surgery or by alcohol septal ablation reduces the pressures of the heart, and that these patients suffer less exertional shortness of breath. Your physicians will discuss the medical, surgical and non-surgical treatment options with you.

Preparation

You and your records (echocardiogram, angiogram, etc.) are evaluated by a HeartPlace cardiologist in their office. You are informed about the many risks, benefits, and treatment options. You will also be contacted to facilitate the education, scheduling, evaluation, and treatment processes.

Procedure

Only patients with severe shortness of breath and with a thickened septum are candidates for alcohol septal ablation. The arterial blood supply (septal perforator vessel) to the thickened part of the muscle is isolated with angiographic and echocardiographic guidance at our cardiac lab. You are sedated during the procedure. A pulmonary artery catheter, a temporary pacemaker wire, and coronary angiographic catheters are inserted from the right neck and femoral approaches. With great care, 1-3 ml of pure alcohol is dripped into one or more small septal arteries. Pressure gradients are measured before and after alcohol infusion to assess the hemodynamic results. The pacemaker is left in place for at least 24 hours. The femoral (groin) catheters are removed later in the day.

How It Works

The alcohol causes necrosis (muscle damage) of the thickened muscle. The heart muscle dies (a heart attack occurs) which leads to thinning of the septum. This allows the heart to function more efficiently, with less leakage of the mitral valve. The results are immediate and they continue to improve over the ensuing six months.

Risks

Risks of the procedure include death during or after hospitalization, heart damage or heart attack in other areas of the heart, severe lung damage, rhythm problems that require a permanent pacer, a defibrillator or medical therapy, stroke, bleeding, need for transfusion, kidney failure or damage leading to temporary or permanent dialysis, vascular damage requiring surgery, cardiac damage or bleeding requiring surgery, contrast or drug allergy, and other risks. Your specific risks are discussed with you during your initial visit. An electrophysiological evaluation may be necessary before or after the alcohol ablation. You may require surgery for placement of a permanent pacemaker or an implantable defibrillator. The early (five-year) results have been very positive; however, the long-term implications of this treatment are unknown, so only severely symptomatic patients are selected for this beneficial but potentially risky procedure.

Hospital Course

After the procedure, you are monitored in the coronary care unit (CCU) for 24 hours. If the rhythm is stable, the temporary pacemaker wire is removed the next day. You are moved out of the CCU and are allowed to ambulate on a telemetry floor on the second day. Some (10%-20%) patients with a normal baseline conduction system of the heart may require permanent pacemaker insertion. If you have certain underlying conduction problems, you may be at higher risk for requiring a permanent pacemaker. You are monitored for a total of three days in the hospital.

Follow-Up Course

The goals of this procedure are to reduce the symptoms of shortness of breath and to allow you to reduce your medication regimen. After discharge, you return for cardiology office follow-up. Repeat echocardiography is performed at the six-month visit. You should report slow heart rate, fainting spells, severe shortness of breath, fever, chills, or right-groin pain. Information is made available to you by the performing cardiologist and his nurse.

Service Providers

Baylor All Saints

Baylor Heart Hospital

HeartPlace Plano