Medical Definitions Medical Definitions and Terminology
How serious is tetralogy of fallot? How to fix tetralogy of fallot? Let’s find out about tetralogy of fallot symptoms and treatment guidelines!
Tetralogy of Fallot Definition
Tetralogy of fallot definition – What is tetralogy of fallot? Tetralogy of fallot is a birth defect that makes it hard for the heart to pump blood normally. It happens when a baby’s heart doesn’t form right while growing and developing in the womb.
Tetralogy of Fallot Causes
What causes tetralogy of fallot? Unfortunately, no one knows for sure what causes tetralogy of Fallot. But some studies suggest that the disorder may be caused by the interaction of several genetic and/or environmental factors (multifactorial).
Patients with tetralogy of Fallot have a VSD, RV infundibular stenosis, RVH, and an enlarged aorta (in about half of patients, it overrides the septum). If there is an ASD, the whole thing is called the “pentalogy of Fallot.” The main problem is a big VSD, and the septum has moved up over the VSD and under the pulmonary valve. There may also be pulmonary valve stenosis, usually caused by an RV outflow hypoplasia or a pulmonary valve with two flaps instead of one.
The aorta can get very big, and aortic regurgitation can happen. It is called a double outlet RV if more than 50% of the aorta goes over the ventricular septum. Two common blood vessel problems are a right-sided aortic arch (which happens in 25% of people) and an abnormal left anterior descending coronary artery from the right cusp (which happens in 7% to 10% of people). This is important because when fixing the RV outflow obstruction, surgery must be careful not to hurt the coronary artery. There may also be a narrowing of the pulmonary branch.
Most adults have already had surgery before. For example, suppose there is a big blockage of the RV outflow when the baby is young. In that case, a systemic arterial to pulmonary artery shunt may be the first step in surgery to improve blood flow to the lungs. However, many babies are fixed without this first step. Most adults, though, will have already had this first repair to ease the pain. The palliative procedure gets blood to the under-perfused lung by either directly connecting one of the subclavian arteries to the main PA branch (classic Blalock shunt) or, more likely, by making a channel between the two (modified Blalock shunt).
Total repair of tetralogy of Fallot usually includes a VSD patch and an enlarging RV outflow tract patch. Any previous arterial-pulmonary artery shunt is also taken down. Suppose the patch on the RV outflow tract goes through the pulmonary valve and into the PA (called a “transannular patch”). In that case, the pulmonary valve backs up to different degrees.
Most surgeons get into the RV through the right atrium and the tricuspid valve and try to avoid a transannular patch if they can. Over time, the main hemodynamic problem adults have to deal with is the volume overload caused by severe pulmonary valve regurgitation that hasn’t gone away. A relative RV volume load is affected by a large RV outflow patch. Ventricular arrhythmias can start at the edge of the VSD or the outflow tract patch, and they tend to happen more often as the RV gets bigger.
Tetralogy of Fallot Diagnosis
Five things are typical:
- VSD.
- Concentric RVH.
- Infundibular stenosis blocks the outflow of blood from the RV.
- In half of the patients, the aorta goes over the septum.
- 25% of people have an aortic arch on the right side.
Most adults with tetralogy of Fallot have had surgery, usually to fix the RV outflow and close the VSD. Pulmonary regurgitation is common if the patch goes over the pulmonary valve annulus.
After a classic tetralogy repair, a physical exam may be misleading, making it hard to find severe pulmonary valve regurgitation.
Echocardiography and Doppler may not pick up on pulmonary valve regurgitation, which is very bad. Be careful if the RV is getting bigger or getting bigger.
Arrhythmias are common, and it’s best to watch them now and then.
Serious arrhythmias and sudden death can happen if either the QRS is wide or the RV gets very big, or if both of these happen.
Tetralogy of Fallot Symptoms
What are the signs and symptoms of tetralogy of fallot?
Signs and symptoms of tetralogy of fallot – Most adults with tetralogy of Fallot who have had surgery to fix it don’t have many symptoms unless they develop right heart failure or arrhythmias. Patients can be active, and most of the time, they don’t need special treatment.
As part of the physical exam, both arms should be checked for lack of pulse that could be caused by a shunt procedure done when the child was younger. The jugular venous pulsations (JVP) may show an increased wave if the RV isn’t moving well or a rare c-v wave if the tricuspid valve isn’t closing properly. The right-side arch doesn’t matter. The precordium may be active, and a pulmonary outflow murmur may not go away. P, might or might not be heard. A gallop to the right may be heard. A VSD or a murmur from the aorta may still go backward.
Tetralogy of Fallot Echocardiography and Radiology
The ECG shows RVH and a change in the right axis. A right bundle branch block pattern is often seen when tetralogy is fixed. The chest x-ray shows a heart that looks like a classic boot, with the RV sticking out and a dip in the RV outflow tract. This may not be as impressive once it’s fixed. The aorta could be bigger and on the right. Importantly, the width of the QRS should be checked every year because a QRS width of more than 180 msec is one of the risks for sudden death. However, newer data suggest that this cutoff is not as accurate as once thought.
Most experts also recommend monitoring the patient while they are out and about, especially if they have palpitations. Other known risk factors for ventricular arrhythmias are having had multiple heart surgeries before, having a high LV end-diastolic pressure (LVEDP), and being older when the repair is done. In addition, it seems that the risk of sudden death increases the more the left side of the heart is involved.
Tetralogy of Fallot Diagnostic Evaluation
Usually, the diagnosis is made with echocardiography or Doppler by looking at the large, unrestricted VSD, the RV infundibular stenosis, and the enlarged aorta. When tetralogy of Fallot has been fixed, echocardiography Doppler can also tell how much residual pulmonary valve regurgitation there is, if there is a transannular patch, how well the RV and LV are working, and if there is aortic regurgitation. High blood levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) have also been linked to an enlarging RV.
MRI and CT scans of the heart can measure both the amount of pulmonary regurgitation and the size of the RV. Also, cardiac MRI and CT can tell if there is a native pulmonary arterial branch stenosis, stenosis at the distal site of a previous arterial-to-PA shunt, or other abnormalities like an ASD. Cardiac MRI is better than other imaging studies because it can accurately measure the severity of pulmonary regurgitation and give more accurate measurements of RV volume.
Because noninvasive studies depend on velocity gradients, it may be necessary to do a cardiac catheterization to find out how bad pulmonary valve regurgitation is. Pulmonary angiography shows how much the pulmonary valve leaks, and RV angiography helps determine if there is an outflow tract aneurysm after surgery.
Some experts say that patients with signs of ventricular tachycardia, unexplained syncope, a wide QRS, who are older, or who are about to get a new pulmonary valve should have an electrophysiologic study with ventricular stimulation and possible ventricular tachycardia ablation.
Tetralogy of Fallot Treatment Guidelines
Treatment of fallot – What is the best treatment for tetralogy of fallot?
Some people with just the right amount of sub pulmonic stenosis make it to adulthood without having surgery. Most adult patients, though, have had surgery to fix the problem. This includes closing the VSD, removing the infundibular muscle, and putting in a patch in the outflow tract to relieve the subpulmonic obstruction.
When a patient has pulmonary valve regurgitation, the RV volume should be watched to ensure it doesn’t get bigger over time. Because the RV diastolic pressures tend to be high and the pulmonary arterial diastolic pressures tend to be low, low-pressure pulmonary valve regurgitation is hard to diagnose. This means there isn’t much difference between the PA and the RV during diastole. This means that color flow Doppler may not show much murmur or turbulence.
If the RV starts to get bigger, it is likely because of pulmonary valve regurgitation until the opposite is shown. Surgical pulmonary valve replacement as soon as possible is becoming increasingly popular. An RV end-diastolic volume index of more than 160 mm/m or an RV end-systolic volume index of more than 80 mm/m is recommended as the cutoff to decide when to intervene if the patient is not showing many symptoms. There are also several other signs that it’s time to step in. The AHA/ACC and ESC guidelines have more information about these.
The diameters of the percutaneous valves that can be used to treat pulmonary valve regurgitation are often too small for the size of the pulmonary annulus. The Melody valve is a prosthesis made from a bovine jugular vein. The biggest size is 22 mm in diameter. Percutaneous stented valves, especially the Edwards SAPIEN XT, have been used successfully and can be used in patients with larger pulmonary roots.
A regular stent is put in the PA first, and then the stented valve is put inside this first stent. The expansion of the PA must not stop blood flow down any coronary artery. This is tested by expanding a trial balloon while taking pictures of the coronary artery (class I requirement). After the Melody valve was put in, there was an increase in stented valve endocarditis. This is being closely watched.
If there is an abnormal coronary artery, a tube from the RV to the PA may need to be put around it as part of the tetralogy repair. By 20-year follow-up, reoperation of the common tetralogy repair is needed in about 10-15%, not only for severe pulmonary valve regurgitation but also for residual infundibular stenosis. Usually, a pulmonary homograft is used to replace the pulmonary valve, but a porcine bioprosthetic valve can also be used.
When a surgical bioprosthetic valve doesn’t work right, percutaneous valve-in-valve stented bioprosthetic valves have been used successfully. Cryoablation of the tissue giving rise to arrhythmias, is sometimes performed at the time of reoperation. By putting in a stent, branch pulmonary stenosis can be opened percutaneously. If the RV outflow obstruction has already been fixed with a conduit, a percutaneous approach with a stented pulmonary valve might be possible. All patients require endocarditis prophylaxis. Most adults can be very active if their blood flow is stable, and most women can carry a baby well if their RV function is kept.
Especially in people over 45, atrial fibrillation, reentrant atrial arrhythmias, and ventricular ectopy are common. Arrhythmias seem to happen more often when the left side of the heart is sick than when the right side is sick. As the patient gets older, biventricular dysfunction is a common result. LV dysfunction is often caused by more than one thing and is hard to figure out. In the same way, the aorta can get bigger along with aortic regurgitation, and these lesions can get bad enough to need surgery. Patients with either the RV or the LV or who have problems with both ventricles may need a defibrillator as a precaution.
All people with tetralogy of Fallot should be sent to a cardiologist specializing in congenital heart disease in adults.
I hope you understand about tetralogy of fallot symptoms and treatment guidelines.
