Overview of Interventions in Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy, or HCM, is a heart disease that happens due to changes in the genes that control the heart muscle. This disease is usually passed down in families and can show up in different ways within different people. HCM causes the wall of the left ventricle (one of the main chambers of the heart) to become thicker than it should be. This is not caused by exercise or other conditions that may otherwise affect the heart’s size.
There are different types of HCM, each having different effects on the heart and leading to different symptoms. These variants include the apical hypertrophic cardiomyopathy, sigmoid septal hypertrophic cardiomyopathy, symmetric septal hypertrophic cardiomyopathy, and asymmetric septal hypertrophic cardiomyopathy. Each of these types affects different parts of the heart and have unique impacts on the body.
Anatomy and Physiology of Interventions in Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy (HCM) is a heart condition where heart cells, known as myocytes, become abnormally large along with an increase in scar tissue due to these cells dying off from lack of oxygen. This is caused by smaller blood vessels not being able to supply enough oxygen to the heart. HCM can cause many changes in how the heart functions, leading to problems like poor oxygen supply to heart tissue, leakage of the heart’s mitral valve, blockade in the blood flow from the left chamber of the heart, and the left chamber of the heart becoming less flexible.
These changes in the heart’s function can lead to symptoms like shortness of breath, chest pain, increased heart rate, or fainting. The smaller blood vessels within the heart muscle walls may also undergo changes, such as their walls becoming thicker, leading to decreased blood flow in the heart and impaired response to widening of the blood vessels.
Because of these changes in heart tissue, those with HCM are also more susceptible to dangerous rapid heart rhythms, which may increase the risk of sudden cardiac death, meaning an unexpected death due to loss of heart function.
Why do People Need Interventions in Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy (HCM) is a heart condition where the heart muscle thickens, making it harder for the heart to pump blood. This can cause an obstruction, or blockage, in the part of the heart that pumps blood to the body – the left ventricular outflow tract. If this obstruction is severe enough, it can interfere with the heart’s function and lead to symptoms such as chest pain, breathlessness, fainting, and palpitations.
People with HCM can start experiencing symptoms at any age and may have a higher risk of sudden heart problems, such as sudden cardiac death. One of the tests doctors use to diagnose this condition and evaluate its severity is called a transthoracic echocardiography. This is an ultrasound test that creates detailed images of your heart, helping doctors to check how well your heart is pumping, and whether there is any blockage in the left ventricular outflow tract, along with other key details about the heart’s structure and function.
This test can show if there are issues with the mitral valve, one of the four valves that control the flow of blood in and out of your heart. In some cases, the mitral valve can be affected by HCM causing it to leak blood back into the heart (mitral regurgitation) or to move abnormally (systolic anterior motion, or SAM). If there is severe leakage unrelated to SAM, surgery might be needed to correct the problem.
Depending on your symptoms, the doctor will work out the best way to manage your condition. This can range from monitoring with no immediate treatment if you do not have symptoms, start medical treatment if you’re slightly symptomatic, or recommend surgery if symptoms are severe and not improving with medication.
In some cases, a device known as an intracardiac defibrillator might be implanted in your heart to reduce your risk of sudden heart problems. This option is especially considered in patients with a significant risk of sudden cardiac death such as those having a family history of HCM with sudden cardiac death and other associated risk factors.
For patients who continue to have symptoms despite being on medication, and who are suitable candidates, alcohol septal ablation can be performed. This procedure involves injecting a small amount of alcohol into the artery that supplies the thickened part of the heart muscle. This causes part of it to die off, reducing the thickness of the heart muscle and improving blood flow out of the heart. It was first described in 1995 as an alternative to surgical treatment for HCM.
When a Person Should Avoid Interventions in Hypertrophic Cardiomyopathy
Here are some key things to know about treatments for a heart condition called hypertrophic cardiomyopathy (HCM), which causes the heart muscles to thicken and may lead to difficulties pumping blood:
– Certain heart drugs known as antiarrhythmics, which are typically used to prevent sudden cardiac death, may not be recommended for HCM patients. This is because of potential side effects and the unclear benefits these drugs provide.
– Radiofrequency ablation, a procedure that uses heat to treat abnormal heart rhythm, may not be used for HCM patients who frequently experience a particular kind of fast heart beat called ventricular tachycardia. This is because these patients often have widespread heart abnormalities that make the treatment less effective.
– Dobutamine, a medication used to help diagnose heart issues by increasing the heart’s output of blood, may not be used in HCM patients who are being assessed for a treatment called alcohol septal ablation. This is due to the medication’s lack of specificity, meaning it may not give an accurate diagnosis.
If a patient with HCM who undergoes alcohol septal ablation (a procedure used to thin the thickened heart muscle) already has a condition where the left side of their heart’s electrical system is blocked (known as left bundle branch block), they may have a high chance of experiencing complete heart block after the procedure. This means that the electrical signals in their heart are completely disrupted, and the heart can’t pump blood properly. In these cases, they may need to have a pacemaker permanently implanted to help regulate their heart’s rhythms.
Equipment used for Interventions in Hypertrophic Cardiomyopathy
The procedure of alcohol septal ablation is a less complex procedure that is usually done while the patient is awake but sedated. The doctor generally makes use of a smaller cut in the arm or leg (referred to as radial or femoral arterial access in medical terms). Ethanol, which is a form of alcohol, is used to reduce the abnormal thickening of the heart muscle through a standard medical balloon that is slid over a wire.
Often, during this procedure, it is not uncommon for certain changes to occur in the heart’s electric activity. This condition, which is often called right bundle-branch block, can usually be managed. Hence, necessary equipment like a temporary pacemaker should be on standby, ready for use by the doctor while they are performing the procedure.
Who is needed to perform Interventions in Hypertrophic Cardiomyopathy?
Hypertrophic cardiomyopathy is a complicated heart condition, and treating it can be challenging. That’s why these treatments should be carried out in advanced, specialized medical centers, known as tertiary care centers, where there are skilled professionals with the right knowledge and experience.
Preparing for Interventions in Hypertrophic Cardiomyopathy
A transthoracic echocardiogram is a type of ultrasound that lets doctors see the inside of your heart. It is often used to identify the specific type of a heart condition called hypertrophic cardiomyopathy or HCM. HCM causes the heart muscle to become thick and this can lead to different shapes and types of thickening, which could appear at the center, the tip, the dividing wall, or unevenly across the heart.
Certain patients with HCM may undergo a procedure called alcohol septal ablation to help improve symptoms. To decide if a patient is a good candidate for this procedure, doctors look at several things:
* First, they check for a specific kind of obstruction in the heart, triggered either at rest or by physical stress, which contributes to the misshaping of the heart.
* They also look at how severe the symptoms are and whether medications are helping to control them. This is measured using a rating system called the New York Heart Association (NYHA) Class, where Class III and IV represent more severe symptoms.
* The doctors also look at the thickness of the heart’s dividing wall, which should be at least 15 millimeters.
* It is also important that the patient does not show significant problems with their mitral valve, a part of the heart that controls the flow of blood.
* And finally, the patient should not already need another heart surgery.
In conclusion, a doctor always considers these criteria before recommending the alcohol septal ablation procedure.
How is Interventions in Hypertrophic Cardiomyopathy performed
Sometimes, the left ventricle (chamber of the heart that pumps oxygen-rich blood to the body) has an abnormal growth that causes blockage or narrowing in the outflow of blood. This condition is known as a left ventricular outflow tract obstruction (LVOT obstruction). If you have this condition, your doctor will measure the severity of the obstruction by calculating gradients (differences in pressure) at rest and during activities that provoke the obstruction. This could include holding your breath, medications, and exercise, among others.
Knowing how severe your LVOT obstruction is helps doctors decide on the best treatment for you. They usually measure it with an ultrasound that creates moving pictures of your heart (a two-dimensional transthoracic echocardiogram). Sometimes though, additional tests like a cardiac MRI or even an invasive catheterization might be necessary.
During catheterization, a small thin tube is inserted into your heart to measure the pressure. There are a couple of ways doctors can do this. They can place a special balloon-tipped tube in your heart via a small hole in your septum (the wall that separates the right and left sides of your heart). They can also insert a tube with two channels into your heart from your aorta (the main artery in your body). Regardless of the technique, the goal is to measure the pressure difference, which indicates the severity of your obstruction.
One way to treat LVOT obstruction is with alcohol septal ablation, a minimally invasive procedure where a small amount of alcohol is injected into the artery supplying blood to the thickened heart muscle, causing it to shrink. Here’s how it’s usually done:
First, the doctor uses a guide tube to help get a special tube (OTW balloon catheter) into the artery causing the problem. They temporarily block the artery by inflating the balloon at the end of the tube. They then remove the guide wire and make sure it fits perfectly to avoid alcohol spilling into other areas. They check it’s completely stopping the blood flow by using an X-ray and do an ultrasound to make sure they’re treating the right part of your heart.
Once they’ve confirmed everything, they inject a high concentration of alcohol slowly over a few minutes, followed by a saline (salt solution) flush. It’s recommended to use no more than 3 milliliters (around half a teaspoon) of alcohol. After the injection, they leave the balloon inflated for around 5 to 10 minutes to prevent the alcohol from leaking out.
After this, they repeat the angiogram (X-ray of your blood vessels) to confirm they successfully treated the targeted artery and ensure the rest of your arteries are still functioning properly. If the obstruction hasn’t reduced significantly, they might need to treat other arteries.
Studies show alcohol septal ablation can reduce the obstruction by 55-75%, with success rates of 80%. The gradients tend to keep reducing for up to 3-6 months after the procedure due to remodeling (changes in the size and shape) of your heart.
Possible Complications of Interventions in Hypertrophic Cardiomyopathy
Before a heart procedure for hypertrophic cardiomyopathy (which is an abnormal thickening of the heart muscle), patients should be fully informed about what the procedure involves. This is especially important if you’re undergoing a type of treatment called alcohol septal ablation. You should know about the long-term survival rates following this procedure, the possibility that you may need a heart pacemaker, whether the procedure is likely to succeed based on the structure of your coronary arteries, and any potential side effects related to the heart catheterization. These can include:
– Coronary dissection: damage to the wall of the coronary artery
– CVA (cerebrovascular accident or stroke): a sudden loss of blood supply to the brain
– Access site bleeding/bruising: bleeding or a bruise where the catheter was inserted
– Contrast-related kidney injury: potential damage to kidneys from the dye (contrast) used during the procedure.
What Else Should I Know About Interventions in Hypertrophic Cardiomyopathy?
In summary, many research studies have found significant improvement in patients who underwent a procedure called septal ablation, a non-surgical procedure that utilizes alcohol to reduce the thickness of the heart wall. This procedure improved both measurable factors (such as how well a patient does on a treadmill test) and patients’ own perceptions of their wellness, including their ability to perform daily activities.
Long-term studies, ranging from 3 months to 8 years, have compared the outcomes of patients who had septal ablation versus those who had a surgical procedure called myomectomy, which removes a part of the heart muscle. These studies largely showed that the survival rates are similar between patients who had either of these procedures.
