What is Aortico-Left Ventricular Tunnel ?
An aorticoventricular tunnel, also known as an “aorto-ventricular tunnel,” is an unusual pathway that forms between the aorta – the main blood vessel that carries blood from your heart to the rest of your body – and a chamber in your heart. Most often, this strange connection happens with the left ventricle – the chamber that pumps oxygen-rich blood into the aorta. However, there are instances when the right ventricle, another pumping chamber, is affected too.
The tunnel usually starts a little above a feature of the heart known as the sinotubular junction, which is located above the valve that opens into the aorta. It’s important to note that this specific starting point sets it apart from another heart condition called a ruptured sinus of Valsalva aneurysm. Similarly, the tunnel doesn’t travel through any of the muscles of your heart on its way to the ventricle, which sets it apart from a coronary-cameral fistula – another abnormal connection that usually forms between a coronary artery and a heart chamber.
Surgeons classify aorticoventricular tunnel cases into four categories, each of which guides how the condition is managed and helps predict its outcome. These classes were introduced in 1988, and they are:
Type I: In this simplest form, the tunnel has a small, slit-like opening in the aorta and doesn’t distort the aorta’s valve.
Type II: This form has an unusual swelling, called an aneurysm, on the external wall of the aorta and an oval opening in the aorta. In this case, there may or may not be any distortion to the valve.
Type III: Unlike the previous type, the aneurism is located inside the heart rather than outside. This type, which also has an oval opening, may or may not block the right ventricle’s output.
Type IV: This type combines features from both Type II and Type III.
Correctly identifying the type of an aorticoventricular tunnel helps guide how the condition should be treated and predict the likely outcome.
What Causes Aortico-Left Ventricular Tunnel ?
We still don’t know exactly what causes aorticoventricular tunnels. Some of the theories are that there could be irregular development of the initial heart muscle that makes up the bottom part of the left heart chamber. Another theory is that the outflow cushions, which help in the movement of blood from the heart, failed to grow properly.
Risk Factors and Frequency for Aortico-Left Ventricular Tunnel
Aortico-left ventricular tunnel is a very rare heart condition. It’s not entirely known how often it occurs, but studies suggest it is found in less than 1% of hearts that have other birth defects. It seems to occur twice as often in men.
About half of the people with this condition also have other heart abnormalities. The most common ones are related to the coronary artery and semilunar valve, bicuspid aortic valve, and enlargement of the ascending aorta.
- Aortico-left ventricular tunnel is an extremely rare heart condition.
- It’s found in less than 1% of hearts with other birth defects.
- It occurs about twice as often in men.
- About half of those with this condition have other heart abnormalities.
- Common associated heart issues include problems with the coronary artery and semilunar valve, bicuspid aortic valve and enlargement of the ascending aorta.
Signs and Symptoms of Aortico-Left Ventricular Tunnel
An aortico-left ventricular tunnel is a heart condition that can cause symptoms relating to heart failure if present. Infants or children with this condition might show signs like rapid breathing, difficulty in breathing, showing intolerance to feeding, and failure to grow properly. On the other hand, adults might experience symptoms such as heart palpitations, chest pain, tiredness, or breathlessness.
During a heart check, an aortico-left ventricular tunnel can cause certain characteristic symptoms. These symptoms include a particular type of heartbeat that feels like it goes to and fro. This sound can be heard all over the precordium, the area of the body that’s in the front of the heart. Patients will often have a normal second heart sound, making this condition different from severe aortic valve regurgitation, where the valve that lets blood out of your heart to the rest of your body (aortic valve) doesn’t close all the way so some blood comes back in. This symptom often comes with low diastolic blood pressure and strong and bounding pulses.
- Rapid breathing
- Difficulty in breathing
- Intolerance to feeding
- Failure to grow properly (in infants and children)
- Heart palpitations
- Chest pain
- Tiredness
- Breathlessness (in adults)
- To-and-froheartbeat
- Normal second heart sound
- Low diastolic blood pressure
- Strong and bounding pulses
Testing for Aortico-Left Ventricular Tunnel
Chest X-Ray
Chest X-rays can help doctors see if a patient has fluid in their lungs or an enlarged heart. They may also show a prominent bulge in the large blood vessel that carries blood from the heart to the rest of the body (the aorta).
Electrocardiogram
An electrocardiogram or EKG is a test that measures the electrical activity of the heart. This can show if the left side of the heart (left ventricle and the left atrium) are larger than normal. Specific changes in the pattern of the heartbeat can indicate this enlargement.
Echocardiogram
An echocardiogram (an ultrasound of the heart) is the main tool doctors use to detect an aortic-left ventricular tunnel – a rare heart defect where there’s an abnormal passageway (tunnel) between the aorta and the left ventricle of the heart. The test can show whether blood is flowing through this tunnel, demonstrate if the area where the heart meets the aorta is wider than normal, and whether the aortic valve is functioning properly. This test can also spot other heart problems that might be present. It’s even possible to spot these tunnels on a fetal echocardiogram – an ultrasound done on an unborn baby – after 18 weeks of pregnancy.
Computed Tomography and Magnetic Resonance Imaging
CT scans and MRI scans show a 3D image of the heart and are particularly valuable in showing the exact location and course of the abnormal tunnel. These imaging techniques are becoming more common in planning for surgery or other heart procedures.
Cardiac Catheterization
Cardiac catheterization is a procedure where a thin plastic tube (catheter) is inserted into the heart through a blood vessel. This test might be used when the diagnosis isn’t clear, or if doctors need a more detailed view of the heart. It can also measure the pressure inside the heart chambers, which can be useful if the patient is experiencing severe heart failure.
Treatment Options for Aortico-Left Ventricular Tunnel
There’s currently no official treatment guideline for aortico-left ventricular tunnels, which are abnormalities between the aorta and the left ventricle of the heart. But, most experts recommend a surgical procedure shortly after diagnosis to close the tunnel and prevent the left ventricle from working too hard. It’s best for this condition to be managed by a supportive team, including a pediatric or adult congenital cardiologist (depending on the patient’s age), a surgeon who specializes in congenital heart conditions, and possibly an interventional cardiologist, a doctor who specializes in heart procedures that use thin, flexible tubes called catheters.
Medical treatment may be offered to help manage the symptoms of heart failure as the patient waits for surgery. For patients who do not have any symptoms, medication is usually not needed before surgery. However, those experiencing symptoms such as shortness of breath, rapid breathing, or problems with growth might need treatment to alleviate symptoms. This could include diuretics such as furosemide or bumetanide, which help eliminate excess fluid from the body.
Patients with mild breathing symptoms can often be managed with oral diuretic medication at home. However, severe respiratory symptoms might need inpatient treatment that could include intravenous diuretic therapy and supplemental oxygen if necessary. Infants experiencing weight loss or slowed weight gain – a condition known as “failure to thrive” – might need additional nutrients provided through a feeding tube or a vein before the surgery.
The most commonly used treatment for an aorticoventricular tunnel is open surgery. The surgery might be modified based on the specific anatomy of the tunnel. The procedure involves opening the chest, placing the heart on a bypass machine, and using a potassium-rich solution to temporarily stop the heart. Once the heart is stopped, the surgeon identifies the origin of the tunnel and outlines its path to the exit point.
Various methods exist for closing the tunnel. This could involve sewing it shut, or inserting a patch on the aorta side or both sides of the tunnel. The patch material can be variable, including Dacron, treated human pericardium, polytetrafluoroethylene, or bovine (cow) pericardium. The repair is completed by closing the aorta. In some cases, an additional procedure may be necessary to remove aneurysmal tissue, or tissue that has developed a ballooning, weakened area.
An alternative to surgery is a procedure that can be performed by an interventional cardiologist, who uses special catheters to fix the tunnel. This involves inserting a device like a plug, disc, or coil into the tunnel to block it. It’s important to note that this option is only suitable for certain patients, and not those with tunnels located near a coronary ostium (an opening into the heart), or those with additional problems like a leaky aortic valve that also needs surgical repair.
What else can Aortico-Left Ventricular Tunnel be?
When someone has a to-and-fro murmur (a type of heart sound) and low blood pressure during the relaxation phase of the heart cycle, it could signal a heart problem where blood is incorrectly shifting within the heart — medical term, intracardiac-shunting lesion. To accurately diagnose this, doctors might consider if one of the following conditions is causing the issue:
- Aortico-left ventricular tunnel – a rare heart defect present at birth
- Patent ductus arteriosus – a persistent opening between two major blood vessels near the heart
- Sinus of valsalva fistula – an abnormal hole in the aorta, the main blood vessel leaving the heart
- Aortic valve regurgitation – leakage of the aortic valve causing blood to flow in the wrong direction
- Aortopulmonary window – a hole in the wall between the aorta and pulmonary artery
A thorough evaluation by the doctor, together with certain diagnostic tests, can help to discern these conditions from one another and work out the best treatment plan.
What to expect with Aortico-Left Ventricular Tunnel
If patients with a condition known as an aortico-left ventricular tunnel do not receive treatment, they usually develop worsening heart failure, although a small number may reach adulthood without any symptoms. Untreated, this condition can lead to complications such as shunts and a faulty aortic valve, which add more strain on the heart, contributing to heart failure.
Treating this condition early usually results in the left ventricle (the heart’s main pumping chamber) eventually returning to its normal size and function, due to decreased strain or volume load. Today’s surgical treatments for aortico-left ventricular tunnels generally have good outcomes.
A recent broad-based medical review found that the death rate within 30 days of the surgery was 8.3%. All these early deaths were associated with ongoing severe problems with the aortic valve and heart failure. For those who survived the early post-operative period, the long-term survival rate was 93.8% after an average follow-up time of 22 years.
Possible Complications When Diagnosed with Aortico-Left Ventricular Tunnel
Patients who have had surgery to correct an aorto-ventricular tunnel could see it reappear or continue to exist, either pretty soon after the initial procedure, or much later down the line. As time goes on, these patients are also at risk of problematic issues such as the aortic valve not closing properly causing some blood to flow back to the heart (a condition known as aortic valvular regurgitation), and the main artery from the heart (the aorta) expanding like a balloon (aneurysmal aortic root dilatation). Therefore, even after a surgical correction of an aortico-left ventricular tunnel, it’s advised that patients have regular checkups with a heart specialist for monitoring and prevention.
Potential Risks:
- Reappearance or continuation of aorto-ventricular tunnel
- Aortic valvular regurgitation
- Aneurysmal aortic root dilatation
Important Preventions:
- Regular checkups with a cardiologist
Recovery from Aortico-Left Ventricular Tunnel
After having surgery to repair the aortico-left ventricular tunnel, all patients are usually taken to a specialized intensive care unit (ICU). This ICU staff includes a group of healthcare professionals who specialize in intensive care treatment (intensivist), heart surgery (cardiac surgeon), anesthesia for heart conditions (cardiac anesthesiologist), and heart disease (cardiologist). For children, it’s important that they are cared for in pediatric units by doctors trained in child health.
Depending on their recovery rate, some patients might need support in the first 24 to 48 hours after surgery, which could include mechanical ventilation (a machine to help them breathe) and hemodynamic support with medication that controls blood pressure and heart function (vasopressors or inotropes). Patients with severe or lasting heart failure before surgery might need more time for their heart function to improve, and thus, need longer stay in the ICU.
Since this type of heart problem is rare, there are no specific guidelines about follow-ups or check-ups after surgery. This process is usually directed by the heart surgeon and cardiologist, based on the individual patient’s condition. If patients have other complications, like other heart defects or inability of the aortic valve to close properly (aortic valve insufficiency), they may need more frequent check-ups. Usually, an echocardiogram — a test that uses sound waves to create pictures of the heart– is performed when the patient is discharged from the hospital and every few months until the heart’s function seems stable. In any case, continuing care under a heart specialist who treats birth defects of the heart (congenital cardiologist) is necessary, even if there are no scheduled imaging tests.
Preventing Aortico-Left Ventricular Tunnel
People diagnosed with aortico-left ventricular tunnel, a heart condition, should continue their regular health check-ups with their doctor. It is also important for these patients to regularly see a heart specialist (cardiologist) for constant monitoring of their heart function throughout their life. The number and length of these follow-up visits can vary depending on how severe the person’s condition is and if there are any remaining issues after treatment.
