Materiały źródłowe

• #1 Tetralogy of Fallot – Wikipedia

  https://en.wikipedia.org/wiki/Tetralogy_of_Fallot

  Embryology studies show that anterior malalignment of the aorticopulmonary septum results in the clinical combination of a ventricular septal defect (VSD), pulmonary stenosis, and an overriding aorta. Right ventricular hypertrophy develops progressively from resistance to blood flow through the right ventricular outflow tract. […] Though the exact cause of TOF is unknown, an association that has been observed is an anterior deviation of the infundibular septum that results in a misaligned VSD, with an overriding aorta causing a subsequent right ventricular obstruction. […] The main anatomic defect in TOF is the anterior deviation of the pulmonary outflow septum. This defect results in narrowing of the right ventricular outflow tract (RVOT), override of the aorta, and a VSD.

• #2 Tetralogy of Fallot pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Tetralogy_of_Fallot_pathophysiology

  Tetralogy of Fallot is a congenital heart lesion characterized by a constellation of four morphologic abnormalities present in the newborn heart. It is understood that tetralogy of fallot is the result of improper positioning of the outlet septum. […] In Tetralogy of Fallot, proper ventricular septation is perturbed by anterocephalad displacement of the outlet septum relative to the septomarginal trabecula. The direct consequence of this misalignment is an overriding aortic orifice and a ventricular septal defect, resulting in an intracardiac right to left shunt of blood. […] Together, the displacement of the outlet septum coupled with the hypertrophic arrangement of the septoparietal trabeculae account for the three anatomical cardinal defects in Tetralogy of Fallot – aortic dextroposition, interventricular communication (VSD), and pulmonary stenosis. The fourth defect – right ventricular hypertrophy – is a hemodynamic consequence of these three morphologic changes, as the right ventricle physiologically adapts to the increased resistance of a stenotic pulmonary trunk.

• #3 Tetralogy of Fallot | Orphanet Journal of Rare Diseases | Full Text

  https://ojrd.biomedcentral.com/articles/10.1186/1750-1172-4-2

  Tetralogy of Fallot is a congenital cardiac malformation that consists of an interventricular communication, also known as a ventricular septal defect, obstruction of the right ventricular outflow tract, override of the ventricular septum by the aortic root, and right ventricular hypertrophy. […] The aetiology is multifactorial, but reported associations include untreated maternal diabetes, phenylketonuria, and intake of retinoic acid. […] The embryological basis of the combination of lesions is antero-cephalad deviation of the developing outlet ventricular septum, or its fibrous remnant should this septum fail to muscularise. […] The combination of the deviated outlet septum and the hypertrophied septoparietal trabeculations produce the characteristic right ventricular outflow tract obstruction of tetralogy of Fallot.

• #4 Tetralogy of Fallot | Pediatric Echocardiography

  https://pedecho.org/library/chd/tetralogy-fallot

  Tetralogy of Fallot (TOF) encompasses a spectrum of cardiac defects that stem from anterocephalad deviation of the outlet septum, along with abnormal septoparietal trabeculations which contribute to right ventricular infundibular narrowing. This leads to the four well-known components of TOF: […] Approximately 25% of patients with TOF have a chromosomal abnormality, most commonly 22q11 deletion (DiGeorge) syndrome followed by trisomy 21. As with other conotruncal defects, TOF is associated with abnormal neural crest cell migration; 22q11 deletion is seen in about 20% of patients with TOF with pulmonary stenosis and in more than 40% of patients with TOF with pulmonary atresia. […] Dynamic obstruction occurs as the hypertrophied RV infundibular muscle contracts, causing further RVOT obstruction over the course of systole.

• #5 Tetralogy of Fallot pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Tetralogy_of_Fallot_pathophysiology

  Tetralogy of Fallot is a congenital heart lesion characterized by a constellation of four morphologic abnormalities present in the newborn heart. It is understood that tetralogy of fallot is the result of improper positioning of the outlet septum. […] In Tetralogy of Fallot, proper ventricular septation is perturbed by anterocephalad displacement of the outlet septum relative to the septomarginal trabecula. The direct consequence of this misalignment is an overriding aortic orifice and a ventricular septal defect, resulting in an intracardiac right to left shunt of blood. […] Together, the displacement of the outlet septum coupled with the hypertrophic arrangement of the septoparietal trabeculae account for the three anatomical cardinal defects in Tetralogy of Fallot – aortic dextroposition, interventricular communication (VSD), and pulmonary stenosis. The fourth defect – right ventricular hypertrophy – is a hemodynamic consequence of these three morphologic changes, as the right ventricle physiologically adapts to the increased resistance of a stenotic pulmonary trunk.

• #6 Tetralogy of Fallot | Orphanet Journal of Rare Diseases | Full Text

  https://ojrd.biomedcentral.com/articles/10.1186/1750-1172-4-2

  Tetralogy of Fallot is a congenital cardiac malformation that consists of an interventricular communication, also known as a ventricular septal defect, obstruction of the right ventricular outflow tract, override of the ventricular septum by the aortic root, and right ventricular hypertrophy. […] The aetiology is multifactorial, but reported associations include untreated maternal diabetes, phenylketonuria, and intake of retinoic acid. […] The embryological basis of the combination of lesions is antero-cephalad deviation of the developing outlet ventricular septum, or its fibrous remnant should this septum fail to muscularise. […] The combination of the deviated outlet septum and the hypertrophied septoparietal trabeculations produce the characteristic right ventricular outflow tract obstruction of tetralogy of Fallot.

• #7 Tetralogy of Fallot pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Tetralogy_of_Fallot_pathophysiology

  Tetralogy of Fallot is a congenital heart lesion characterized by a constellation of four morphologic abnormalities present in the newborn heart. It is understood that tetralogy of fallot is the result of improper positioning of the outlet septum. […] In Tetralogy of Fallot, proper ventricular septation is perturbed by anterocephalad displacement of the outlet septum relative to the septomarginal trabecula. The direct consequence of this misalignment is an overriding aortic orifice and a ventricular septal defect, resulting in an intracardiac right to left shunt of blood. […] Together, the displacement of the outlet septum coupled with the hypertrophic arrangement of the septoparietal trabeculae account for the three anatomical cardinal defects in Tetralogy of Fallot – aortic dextroposition, interventricular communication (VSD), and pulmonary stenosis. The fourth defect – right ventricular hypertrophy – is a hemodynamic consequence of these three morphologic changes, as the right ventricle physiologically adapts to the increased resistance of a stenotic pulmonary trunk.

• #8 Tetralogy of Fallot – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK513288/

  Tetralogy of Fallot (TOF) is a conotruncal cardiac defect characterized by a large and anteriorly malaligned ventricular septal defect, an overriding aortic root, and narrowing of the subpulmonary and pulmonary valves. […] The VSD in TOF is typically large or nonrestrictive, allowing pressure equalization within the ventricles. Therefore, whether the shunting is left to right or vice versa will depend on the degree of downstream pressure the blood flow encounters. […] Different factors can contribute to RVOTO, including a stenotic pulmonary valve, a hypoplastic pulmonary valve annulus, the deviation of the infundibular septum that causes subvalvular obstruction, and the hypertrophy of the muscular bands of the RVOT. […] The obstruction across the RVOT can also be dynamic with sudden increases in cyanosis, a phenomenon known as Tet or hypoxic spells.

• #9 Cardiovascular System – Tetralogy of Fallot – Embryology

  https://embryology.med.unsw.edu.au/embryology/index.php/Cardiovascular_System_-_Tetralogy_of_Fallot

  Tetralogy of Fallot is a common developmental cardiac defect. The syndrome consists of a number of cardiac defects possibly stemming from abnormal neural crest migration. Tetralogy refers to a set of four related symptoms or abnormalities frequently occurring together. […] This cardiovascular abnormality has also been researched as a 2011 Student Project. […] The aortic root is overriding the crest of the muscular ventricular septum, in presence of a large interventricular communication. The muscular outlet septum is deviated antero-cranially, and is located exclusively within the right ventricle. Together with the hypertrophied trabeculations on the parietal wall of the right ventricle, it produces muscular subpulmonary obstruction. The walls of the right ventricle are hypertrophied, producing the fourth feature of the tetralogy.

• #10 Tetralogy of Fallot – Pediatrics – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/pediatrics/congenital-cardiovascular-anomalies/tetralogy-of-fallot

  The ventricular septal defect in tetralogy of Fallot is often described as a malalignment type, since the conal septum is displaced anteriorly. This displaced septum protrudes into the pulmonary outflow tract, often resulting in obstruction and hypoplasia of the downstream structures, including the pulmonary valve, main pulmonary artery, and branch pulmonary arteries. The ventricular septal defect (VSD) is typically large; thus, systolic pressures in the right and left ventricles (and in the aorta) are the same. Pathophysiology depends on the degree of right ventricular outflow obstruction. A mild obstruction may result in a net left-to-right shunt through the VSD; a severe obstruction causes a right-to-left shunt, resulting in low systemic arterial saturation (cyanosis) that is unresponsive to supplemental oxygen.

• #11 Tetralogy of Fallot- Pathophysiology -Managment- TeachMePaediatrics

  https://teachmepaediatrics.com/cardiology/congenital-heart-defects/tetralogy-of-fallot/

  Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease thus its important to have a good understanding of the condition. As the name implies, it is a tetrad of: Ventricular septal defect (VSD), Pulmonary stenosis (PS), Right ventricular hypertrophy (RVH), Overriding aorta. […] To better explain the pathophysiology of TOF, we should explore the 4 lesions in greater depth: VSDs are categorised according to their location on the ventricular septum. The smaller membranous septum is located on the superior aspect whilst the larger muscular septum is on the inferior aspect. When the VSD involves parts of the membranous and muscular septum, this is called a perimembranous VSD this is the commonest type associated with TOF. Other VSDs associated with TOF are muscular VSDs and doubly committed VSDs (located near both pulmonary and aortic valves). The VSD is normally of a significant size, which causes the systolic pressures between the ventricles to equalise. In mild TOF, the left ventricular pressures remain higher than the right ventricle, thus blood shunts from left-to-right through the VSD. These patients are normally acyanotic. In more severe disease, due to increased right ventricular pressure (secondary to PS see below) the shunt direction reverses from right-to-left allowing mixing of deoxygenated (blue) and oxygenated (red) blood. This results in lower oxygenated (purple) blood in the systemic circulation, hence patients are cyanotic.

• #12 Tetralogy of Fallot- Pathophysiology -Managment- TeachMePaediatrics

  https://teachmepaediatrics.com/cardiology/congenital-heart-defects/tetralogy-of-fallot/

  Pulmonary stenosis can be classified according to its location. The commonest site is the infundibular septum (50%). Some authors use the more descriptive term right ventricular outflow tract (RVOT) but they essentially refer to the same thing. The stenosis may also be valvular (10%) or a combination of both (30%). This results in impaired flow of deoxygenated blood into the main pulmonary artery (PA). It may be severe enough to cause intermittent RVOT obstruction (RVOTO) – this forms the basis of hypoxic episodes, commonly known as tet spells. […] Hypertrophy of the right ventricle occurs in response to the high pressures it must overcome to pump deoxygenated blood through the RVOTO. This usually develops in utero and may be seen in chest x-rays as the boot sign. […] Compared to the normal heart, the aorta in TOF is dilated and displaced over the intraventricular septum. Aortic dilatation is caused by an increase in blood flow through the aorta as it receives blood from both ventricles via the VSD. In severe TOF, multiple aorto-pulmonary collateral arteries (MAPCAs) may also form to help increase pulmonary blood flow.

• #13 Tetralogy of Fallot | Symptoms, Diagnosis & Treatment

  https://www.cincinnatichildrens.org/health/t/tof

  Tetralogy of Fallot (TOF) is a cardiac anomaly that refers to a combination of four related heart defects that commonly occur together. The four defects are: Ventricular septal defect (VSD), Overriding aorta the aortic valve is enlarged and appears to arise from both the left and right ventricles instead of the left ventricle as in normal hearts, Pulmonary stenosis narrowing of the pulmonary valve and outflow tract or area below the valve that creates an obstruction (blockage) of blood flow from the right ventricle to the pulmonary artery, Right ventricular hypertrophy thickening of the muscular walls of the right ventricle, which occurs because the right ventricle is pumping at high pressure. […] Tetralogy of Fallot may be associated with chromosomal abnormalities, such as 22q11 deletion syndrome. It is important that this be identified so that other conditions can be treated.

• #14 Tetralogy of Fallot- Pathophysiology -Managment- TeachMePaediatrics

  https://teachmepaediatrics.com/cardiology/congenital-heart-defects/tetralogy-of-fallot/

  Pulmonary stenosis can be classified according to its location. The commonest site is the infundibular septum (50%). Some authors use the more descriptive term right ventricular outflow tract (RVOT) but they essentially refer to the same thing. The stenosis may also be valvular (10%) or a combination of both (30%). This results in impaired flow of deoxygenated blood into the main pulmonary artery (PA). It may be severe enough to cause intermittent RVOT obstruction (RVOTO) – this forms the basis of hypoxic episodes, commonly known as tet spells. […] Hypertrophy of the right ventricle occurs in response to the high pressures it must overcome to pump deoxygenated blood through the RVOTO. This usually develops in utero and may be seen in chest x-rays as the boot sign. […] Compared to the normal heart, the aorta in TOF is dilated and displaced over the intraventricular septum. Aortic dilatation is caused by an increase in blood flow through the aorta as it receives blood from both ventricles via the VSD. In severe TOF, multiple aorto-pulmonary collateral arteries (MAPCAs) may also form to help increase pulmonary blood flow.

• #15 Tetralogy of Fallot pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Tetralogy_of_Fallot_pathophysiology

  Tetralogy of Fallot is a congenital heart lesion characterized by a constellation of four morphologic abnormalities present in the newborn heart. It is understood that tetralogy of fallot is the result of improper positioning of the outlet septum. […] In Tetralogy of Fallot, proper ventricular septation is perturbed by anterocephalad displacement of the outlet septum relative to the septomarginal trabecula. The direct consequence of this misalignment is an overriding aortic orifice and a ventricular septal defect, resulting in an intracardiac right to left shunt of blood. […] Together, the displacement of the outlet septum coupled with the hypertrophic arrangement of the septoparietal trabeculae account for the three anatomical cardinal defects in Tetralogy of Fallot – aortic dextroposition, interventricular communication (VSD), and pulmonary stenosis. The fourth defect – right ventricular hypertrophy – is a hemodynamic consequence of these three morphologic changes, as the right ventricle physiologically adapts to the increased resistance of a stenotic pulmonary trunk.

• #16 Tetralogy of Fallot

  https://ilearn.courses.med.fiu.edu/published/umedic_cardiology/tet/pathDiscussion1.html

  Tetralogy of Fallot is a pathologic complex based upon anterior displacement of the truncoconal septum of the developing embryo heart. As a result of this error, the conus septum, which forms the crista supraventricularis, cannot fuse with the ventricular septum. This results in a large ventricular septal defect located below the crista. Anterior displacement of the conus septum also narrows the right ventricular outflow tract, creating obstruction. Anterior displacement of the truncal septum narrows the pulmonary valve annulus and pulmonary artery, adding to the obstruction. […] The ventricular septal defect and right ventricular outflow tract obstruction are the most significant of the four components of tetralogy of Fallot. Right ventricular hypertrophy occurs because right ventricular systolic pressure equals that of the left ventricle. Overriding of the aorta refers to the anatomic relationship of the aortic annulus stride the ventricular septal defect. This comes about because both the VSD and the ascending aorta are large. It is, therefore, more an apparent than a real abnormality.

• #17 Tetralogy of Fallot (TOF) in Adults: Practice Essentials, Background, Anatomy

  https://emedicine.medscape.com/article/2035949-overview

  Tetralogy of Fallot (TOF) is one of the most common congenital heart disorders. The basic pathology of tetralogy is due to the underdevelopment of the RV infundibulum, which results in an anterior-leftward malalignment of the infundibular septum. This malalignment determines the degree of RV outflow tract obstruction (RVOTO). […] The hemodynamics of tetralogy of Fallot depends on the degree of right ventricular (RV) outflow tract obstruction (RVOTO). The ventricular septal defect (VSD) is usually nonrestrictive, and the RV and left ventricular pressures are equalized. If the obstruction is severe, the intracardiac shunt is from right to left, and pulmonary blood flow may be markedly diminished. […] The RV dilatation from the pulmonary valve insufficiency is associated with fibrosis and severe myocardial damage, which then often lead to a decrease in exercise endurance, and the majority of patients soon develop ventricular arrhythmias. […] The arrhythmias occur as a result of progressive dilatation and stretching of the right atrium and RV.

• #18 Tetralogy of Fallot – Cardiothoracic Surgery

  https://lsom.uthscsa.edu/ct-surgery/patient-care/congenital-heart/conditions-we-treat/tetralogy-of-fallot/

  Tetralogy of Fallot refers to the constellation of VSD, right ventricular outflow tract (RVOT) obstruction (ie: pulmonary stenosis), right ventricular hypertrophy (RVH), and an overriding aorta. […] The VSD is usually large and unrestrictive, and the direction and severity of shunting depend upon the degree of RVOT obstruction. […] The higher the obstruction to blood flow exiting the RV to the PA, the more blood which will be forced across the VSD. This in turn determines the degree of cyanosis and the age of presentation. […] Patients with mild RVOT obstruction may have normal oxygen saturations and predominantly left-to-right shunting through the VSD (acyanotic or “pink” tetralogy), while those with severe RVOT obstruction will have significant right-to-left shunting and present early in infancy with cyanosis.

• #19 Tetralogy of Fallot in Animals – Circulatory System – Merck Veterinary Manual

  https://www.merckvetmanual.com/circulatory-system/congenital-and-inherited-anomalies-of-the-cardiovascular-system/tetralogy-of-fallot-in-animals

  Tetralogy of Fallot is an uncommon but complex congenital defect comprised of pulmonic stenosis, ventricular septal defect, right ventricular hypertrophy, and overriding aorta. […] A single conotruncal malformation (cranially displaced formation of the upper portion of the interventricular septum) is believed to result in narrowing of the right ventricular outflow tract (pulmonic stenosis), overriding of the aorta, and the ventricular septal defect. […] The hemodynamic consequences of tetralogy of Fallot depend primarily on the severity of the pulmonic stenosis, the size of the ventricular septal defect (which is typically large and nonrestrictive), and the ratio of pulmonary to systemic vascular resistance. […] Right-to-left shunting across the ventricular septal defect may result in generalized cyanosis and polycythemia. […] Tetralogy of Fallot is a complex heart disease with four components: pulmonic stenosis, ventricular septal defect, right ventricular concentric hypertrophy, and dextropositioned (overriding) aorta.

• #20 Tetralogy of Fallot- Pathophysiology -Managment- TeachMePaediatrics

  https://teachmepaediatrics.com/cardiology/congenital-heart-defects/tetralogy-of-fallot/

  Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease thus its important to have a good understanding of the condition. As the name implies, it is a tetrad of: Ventricular septal defect (VSD), Pulmonary stenosis (PS), Right ventricular hypertrophy (RVH), Overriding aorta. […] To better explain the pathophysiology of TOF, we should explore the 4 lesions in greater depth: VSDs are categorised according to their location on the ventricular septum. The smaller membranous septum is located on the superior aspect whilst the larger muscular septum is on the inferior aspect. When the VSD involves parts of the membranous and muscular septum, this is called a perimembranous VSD this is the commonest type associated with TOF. Other VSDs associated with TOF are muscular VSDs and doubly committed VSDs (located near both pulmonary and aortic valves). The VSD is normally of a significant size, which causes the systolic pressures between the ventricles to equalise. In mild TOF, the left ventricular pressures remain higher than the right ventricle, thus blood shunts from left-to-right through the VSD. These patients are normally acyanotic. In more severe disease, due to increased right ventricular pressure (secondary to PS see below) the shunt direction reverses from right-to-left allowing mixing of deoxygenated (blue) and oxygenated (red) blood. This results in lower oxygenated (purple) blood in the systemic circulation, hence patients are cyanotic.

• #21 Tetralogy of Fallot – Cardiothoracic Surgery

  https://lsom.uthscsa.edu/ct-surgery/patient-care/congenital-heart/conditions-we-treat/tetralogy-of-fallot/

  Tetralogy of Fallot refers to the constellation of VSD, right ventricular outflow tract (RVOT) obstruction (ie: pulmonary stenosis), right ventricular hypertrophy (RVH), and an overriding aorta. […] The VSD is usually large and unrestrictive, and the direction and severity of shunting depend upon the degree of RVOT obstruction. […] The higher the obstruction to blood flow exiting the RV to the PA, the more blood which will be forced across the VSD. This in turn determines the degree of cyanosis and the age of presentation. […] Patients with mild RVOT obstruction may have normal oxygen saturations and predominantly left-to-right shunting through the VSD (acyanotic or “pink” tetralogy), while those with severe RVOT obstruction will have significant right-to-left shunting and present early in infancy with cyanosis.

• #22 Tetralogy of Fallot- Pathophysiology -Managment- TeachMePaediatrics

  https://teachmepaediatrics.com/cardiology/congenital-heart-defects/tetralogy-of-fallot/

  Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease thus its important to have a good understanding of the condition. As the name implies, it is a tetrad of: Ventricular septal defect (VSD), Pulmonary stenosis (PS), Right ventricular hypertrophy (RVH), Overriding aorta. […] To better explain the pathophysiology of TOF, we should explore the 4 lesions in greater depth: VSDs are categorised according to their location on the ventricular septum. The smaller membranous septum is located on the superior aspect whilst the larger muscular septum is on the inferior aspect. When the VSD involves parts of the membranous and muscular septum, this is called a perimembranous VSD this is the commonest type associated with TOF. Other VSDs associated with TOF are muscular VSDs and doubly committed VSDs (located near both pulmonary and aortic valves). The VSD is normally of a significant size, which causes the systolic pressures between the ventricles to equalise. In mild TOF, the left ventricular pressures remain higher than the right ventricle, thus blood shunts from left-to-right through the VSD. These patients are normally acyanotic. In more severe disease, due to increased right ventricular pressure (secondary to PS see below) the shunt direction reverses from right-to-left allowing mixing of deoxygenated (blue) and oxygenated (red) blood. This results in lower oxygenated (purple) blood in the systemic circulation, hence patients are cyanotic.

• #23 Tetralogy of Fallot – Cardiothoracic Surgery

  https://lsom.uthscsa.edu/ct-surgery/patient-care/congenital-heart/conditions-we-treat/tetralogy-of-fallot/

  Tetralogy of Fallot refers to the constellation of VSD, right ventricular outflow tract (RVOT) obstruction (ie: pulmonary stenosis), right ventricular hypertrophy (RVH), and an overriding aorta. […] The VSD is usually large and unrestrictive, and the direction and severity of shunting depend upon the degree of RVOT obstruction. […] The higher the obstruction to blood flow exiting the RV to the PA, the more blood which will be forced across the VSD. This in turn determines the degree of cyanosis and the age of presentation. […] Patients with mild RVOT obstruction may have normal oxygen saturations and predominantly left-to-right shunting through the VSD (acyanotic or “pink” tetralogy), while those with severe RVOT obstruction will have significant right-to-left shunting and present early in infancy with cyanosis.

• #24 Tetralogy of Fallot (ToF) – RCEMLearning

  https://www.rcemlearning.co.uk/modules/congenital-heart-disease-in-the-emergency-department/lessons/righttoleft-shunts/topic/tetralogy-of-fallot-tof/

  TOF is the most common cause of cyanotic CHD. […] The pathophysiology relates to shunting of desaturated, systemic venous blood through the VSD to mix with the systemic cardiac output. […] The greater the degree of obstruction to pulmonary blood flow, the larger the right-to-left shunt and the worse the desaturation. […] Right ventricular outflow tract obstruction: determines the amount of cyanosis. […] The direction of shunt depends on the extent of right ventricular outflow tract obstruction. The VSD is almost never restrictive in tetralogy of Fallot.

• #25 Tetralogy of Fallot (TOF) in Adults: Practice Essentials, Background, Anatomy

  https://emedicine.medscape.com/article/2035949-overview

  Tetralogy of Fallot (TOF) is one of the most common congenital heart disorders. The basic pathology of tetralogy is due to the underdevelopment of the RV infundibulum, which results in an anterior-leftward malalignment of the infundibular septum. This malalignment determines the degree of RV outflow tract obstruction (RVOTO). […] The hemodynamics of tetralogy of Fallot depends on the degree of right ventricular (RV) outflow tract obstruction (RVOTO). The ventricular septal defect (VSD) is usually nonrestrictive, and the RV and left ventricular pressures are equalized. If the obstruction is severe, the intracardiac shunt is from right to left, and pulmonary blood flow may be markedly diminished. […] The RV dilatation from the pulmonary valve insufficiency is associated with fibrosis and severe myocardial damage, which then often lead to a decrease in exercise endurance, and the majority of patients soon develop ventricular arrhythmias. […] The arrhythmias occur as a result of progressive dilatation and stretching of the right atrium and RV.

• #26 Tetralogy of Fallot – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK513288/

  Tetralogy of Fallot (TOF) is a conotruncal cardiac defect characterized by a large and anteriorly malaligned ventricular septal defect, an overriding aortic root, and narrowing of the subpulmonary and pulmonary valves. […] The VSD in TOF is typically large or nonrestrictive, allowing pressure equalization within the ventricles. Therefore, whether the shunting is left to right or vice versa will depend on the degree of downstream pressure the blood flow encounters. […] Different factors can contribute to RVOTO, including a stenotic pulmonary valve, a hypoplastic pulmonary valve annulus, the deviation of the infundibular septum that causes subvalvular obstruction, and the hypertrophy of the muscular bands of the RVOT. […] The obstruction across the RVOT can also be dynamic with sudden increases in cyanosis, a phenomenon known as Tet or hypoxic spells.

• #27 Tetralogy of Fallot – Pediatrics – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/pediatrics/congenital-cardiovascular-anomalies/tetralogy-of-fallot

  The mechanism of a hypercyanotic spell remains uncertain, but several factors are probably important in causing an increase in right-to-left shunting and a fall in arterial oxygen saturation. Factors include […] An increase in right ventricular outflow tract obstruction […] An increase in pulmonary vascular resistance […] A decrease in systemic resistance. […] These factors lead to a vicious circle caused by the initial fall in arterial PO2, which stimulates the respiratory center and causes hyperpnea and increased adrenergic tone. The increased circulating catecholamines then stimulate increased contractility, which increases outflow tract obstruction.

• #28 Tetralogy of Fallot – Pediatrics – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/pediatrics/congenital-cardiovascular-anomalies/tetralogy-of-fallot

  The mechanism of a hypercyanotic spell remains uncertain, but several factors are probably important in causing an increase in right-to-left shunting and a fall in arterial oxygen saturation. Factors include […] An increase in right ventricular outflow tract obstruction […] An increase in pulmonary vascular resistance […] A decrease in systemic resistance. […] These factors lead to a vicious circle caused by the initial fall in arterial PO2, which stimulates the respiratory center and causes hyperpnea and increased adrenergic tone. The increased circulating catecholamines then stimulate increased contractility, which increases outflow tract obstruction.

• #29 Tetralogy of Fallot | Pediatric Echocardiography

  https://pedecho.org/library/chd/tetralogy-fallot

  Tetralogy of Fallot (TOF) encompasses a spectrum of cardiac defects that stem from anterocephalad deviation of the outlet septum, along with abnormal septoparietal trabeculations which contribute to right ventricular infundibular narrowing. This leads to the four well-known components of TOF: […] Approximately 25% of patients with TOF have a chromosomal abnormality, most commonly 22q11 deletion (DiGeorge) syndrome followed by trisomy 21. As with other conotruncal defects, TOF is associated with abnormal neural crest cell migration; 22q11 deletion is seen in about 20% of patients with TOF with pulmonary stenosis and in more than 40% of patients with TOF with pulmonary atresia. […] Dynamic obstruction occurs as the hypertrophied RV infundibular muscle contracts, causing further RVOT obstruction over the course of systole.

• #30 Tetralogy of Fallot – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK513288/

  The physiological process surrounding these hypercyanotic episodes is yet to be fully understood but appears to involve a decrease in systemic vascular resistance or an increase in pulmonary vascular resistance. […] Patients with TOF and pulmonary atresia are usually cyanotic in the newborn period, with worsening cyanosis as the ductus arteriosus closes. […] The clinical presentation will also depend on the associated cardiovascular anomalies in roughly 40% of patients with TOF. […] Approximately 75% to 80% of TOF cases are nonsyndromic, meaning that the patient has an isolated cardiac defect. […] In conotruncal malformations, suppression of developmental networks such as the NOTCH and WNT pathways during early embryogenesis produces malfunction of downstream regulatory pathways that lead to faulty structural cardiac development.

• #31 Understanding Tetralogy of Fallot Pathophysiology

  https://sunfox.in/blogs/understanding-tetralogy-of-fallot-pathophysiology/?srsltid=AfmBOorE66n2Qkfuee9JeZ0XDU6JSwQ2BrZauOEhVlhr7eBLkcv31U_J

  Pulmonary stenosis restricts blood flow from the right ventricle to the lungs, increasing the pressure in the right ventricle (right ventricular hypertrophy) and forcing the heart to work harder. […] The overriding aorta receives blood from both ventricles, further contributing to the mixing of oxygenated and deoxygenated blood. This structural anomaly exacerbates systemic hypoxemia, leading to the clinical symptoms associated with TOF. […] Right ventricular hypertrophy develops as the right ventricle adapts to the increased pressure workload caused by pulmonary stenosis. […] The hemodynamic abnormalities in TOF lead to several critical physiological changes: Hypoxemia and Cyanosis: Due to the mixing of oxygenated and deoxygenated blood, less oxygen is delivered to the tissues, causing cyanosis.

• #32 Tetralogy of Fallot- Pathophysiology -Managment- TeachMePaediatrics

  https://teachmepaediatrics.com/cardiology/congenital-heart-defects/tetralogy-of-fallot/

  Pulmonary stenosis can be classified according to its location. The commonest site is the infundibular septum (50%). Some authors use the more descriptive term right ventricular outflow tract (RVOT) but they essentially refer to the same thing. The stenosis may also be valvular (10%) or a combination of both (30%). This results in impaired flow of deoxygenated blood into the main pulmonary artery (PA). It may be severe enough to cause intermittent RVOT obstruction (RVOTO) – this forms the basis of hypoxic episodes, commonly known as tet spells. […] Hypertrophy of the right ventricle occurs in response to the high pressures it must overcome to pump deoxygenated blood through the RVOTO. This usually develops in utero and may be seen in chest x-rays as the boot sign. […] Compared to the normal heart, the aorta in TOF is dilated and displaced over the intraventricular septum. Aortic dilatation is caused by an increase in blood flow through the aorta as it receives blood from both ventricles via the VSD. In severe TOF, multiple aorto-pulmonary collateral arteries (MAPCAs) may also form to help increase pulmonary blood flow.

• #33 Understanding Tetralogy of Fallot Pathophysiology

  https://sunfox.in/blogs/understanding-tetralogy-of-fallot-pathophysiology/?srsltid=AfmBOorE66n2Qkfuee9JeZ0XDU6JSwQ2BrZauOEhVlhr7eBLkcv31U_J

  Pulmonary stenosis restricts blood flow from the right ventricle to the lungs, increasing the pressure in the right ventricle (right ventricular hypertrophy) and forcing the heart to work harder. […] The overriding aorta receives blood from both ventricles, further contributing to the mixing of oxygenated and deoxygenated blood. This structural anomaly exacerbates systemic hypoxemia, leading to the clinical symptoms associated with TOF. […] Right ventricular hypertrophy develops as the right ventricle adapts to the increased pressure workload caused by pulmonary stenosis. […] The hemodynamic abnormalities in TOF lead to several critical physiological changes: Hypoxemia and Cyanosis: Due to the mixing of oxygenated and deoxygenated blood, less oxygen is delivered to the tissues, causing cyanosis.

• #34 Tetralogy of Fallot (TOF) | Boston Children’s Hospital

  https://www.childrenshospital.org/conditions/tetralogy-fallot

  The restricted blood flow to the lungs caused by TOF normally worsens with time. Sometimes, the pulmonary valve, providing one-way blood flow between the right ventricle and the lungs, is completely obstructed. This is a more severe form of TOF called tetralogy of Fallot with pulmonary atresia. […] Most cases of TOF have no genetic association. However, there are some cases with a genetic link. Parents who already have a child with a congenital heart defect are slightly more likely to have a second child with a heart defect. […] Almost all children with tetralogy of Fallot will need surgery. Many children can be treated medically until a complete repair can be done. More severe forms of TOF may require early intervention, including hospitalization. […] Full surgical repair of TOF consists of: Closing the ventricular septal defect (VSD) between the right and left ventricles. Relieving the narrowing between the right ventricle and the pulmonary artery.

• #35 Tetralogy of Fallot (TOF) in Adults Clinical Presentation: History, Physical Examination

  https://emedicine.medscape.com/article/2035949-clinical

  The mechanism is thought to include spasm of the infundibular septum, which acutely worsens the right ventricular (RV) outflow tract obstruction. […] Symptoms generally progress secondary to hypertrophy of the infundibular septum. Worsening of the RV outflow tract obstruction leads to RV hypertrophy, increased right-to-left shunting, and systemic hypoxemia. […] Even after surgery it is important to understand that despite the curative approach to surgery, it is simply a long-term palliative procedure. The surgery only corrects the anatomic abnormality; it does not address the cause and does not prevent the ongoing anatomic changes in the RV and pulmonary vessels. Hence, sooner or later, most patients with corrective surgery will present with some type of symptom related to dysfunction of the RV and RV outflow tract obstruction.

• #36 Tetralogy of Fallot (TOF) | Boston Children’s Hospital

  https://www.childrenshospital.org/conditions/tetralogy-fallot

  The restricted blood flow to the lungs caused by TOF normally worsens with time. Sometimes, the pulmonary valve, providing one-way blood flow between the right ventricle and the lungs, is completely obstructed. This is a more severe form of TOF called tetralogy of Fallot with pulmonary atresia. […] Most cases of TOF have no genetic association. However, there are some cases with a genetic link. Parents who already have a child with a congenital heart defect are slightly more likely to have a second child with a heart defect. […] Almost all children with tetralogy of Fallot will need surgery. Many children can be treated medically until a complete repair can be done. More severe forms of TOF may require early intervention, including hospitalization. […] Full surgical repair of TOF consists of: Closing the ventricular septal defect (VSD) between the right and left ventricles. Relieving the narrowing between the right ventricle and the pulmonary artery.

• #37 Tetralogy of Fallot – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK513288/

  The physiological process surrounding these hypercyanotic episodes is yet to be fully understood but appears to involve a decrease in systemic vascular resistance or an increase in pulmonary vascular resistance. […] Patients with TOF and pulmonary atresia are usually cyanotic in the newborn period, with worsening cyanosis as the ductus arteriosus closes. […] The clinical presentation will also depend on the associated cardiovascular anomalies in roughly 40% of patients with TOF. […] Approximately 75% to 80% of TOF cases are nonsyndromic, meaning that the patient has an isolated cardiac defect. […] In conotruncal malformations, suppression of developmental networks such as the NOTCH and WNT pathways during early embryogenesis produces malfunction of downstream regulatory pathways that lead to faulty structural cardiac development.

• #38 About Tetralogy of Fallot | Congenital Heart Defects (CHDs) | CDC

  https://www.cdc.gov/heart-defects/about/tetralogy-of-fallot.html

  Tetralogy of Fallot occurs when a babys heart does not form correctly during pregnancy. […] The causes of tetralogy of Fallot among most babies are unknown. Some babies have heart defects because of changes in their genes or chromosomes. A combination of genes and other risk factors may increase the risk for tetralogy of Fallot. These factors can include things in a mother’s environment, what she eats or drinks, or the medicines she uses. […] Tetralogy of Fallot can be treated by surgery soon after the baby is born. During surgery, doctors widen or replace the pulmonary valve and enlarge the passage to the pulmonary artery. They also will place a patch over the VSD to close the hole between the two lower chambers of the heart. These actions will improve blood flow to the lungs and the rest of the body.

• #39 Tetralogy of Fallot – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK513288/

  The physiological process surrounding these hypercyanotic episodes is yet to be fully understood but appears to involve a decrease in systemic vascular resistance or an increase in pulmonary vascular resistance. […] Patients with TOF and pulmonary atresia are usually cyanotic in the newborn period, with worsening cyanosis as the ductus arteriosus closes. […] The clinical presentation will also depend on the associated cardiovascular anomalies in roughly 40% of patients with TOF. […] Approximately 75% to 80% of TOF cases are nonsyndromic, meaning that the patient has an isolated cardiac defect. […] In conotruncal malformations, suppression of developmental networks such as the NOTCH and WNT pathways during early embryogenesis produces malfunction of downstream regulatory pathways that lead to faulty structural cardiac development.

• #40 Tetralogy of Fallot – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK513288/

  The remaining 20% to 25% of patients with TOF have an associated syndrome or a chromosomal abnormality, with the most frequent being trisomy 21 (ie, Down syndrome) and the 22q11.2 deletion syndromes. […] Thus, genetic testing is currently recommended in fetuses with TOF to assess for the 22q11.2 microdeletion, especially since outcomes are worse than in those who do not carry the microdeletion. […] The ductus arteriosus is usually absent, and approximately 50% have a right-sided aortic arch. […] Surgical repair requires unifocalization of the many aortopulmonary collaterals, which can be quite challenging. […] The clinical manifestations of patients with TOF and absent pulmonary valves depend on the severity of respiratory distress, ranging from those with no respiratory distress to those with severe respiratory distress due to trachea and main stem bronchi compression by the massive pulmonary artery branches. […] The degree of obstructive airway disease among these patients varies markedly. […] The prognosis of these patients is also affected by the need for pulmonary valve replacement due to progressive pulmonary insufficiency, which places them at risk of bacterial endocarditis.

• #41 Tetralogy of Fallot: Risks and Management in Adulthood – Clinical Advisor

  https://www.clinicaladvisor.com/features/tetralogy-of-fallot-in-adulthood/

  It has been proposed that during development, a portion of the ventricular septum is displaced anteriorly into the right ventricular outflow tract (RVOT); however, the exact etiology of TOF is not fully understood. The most common associations are genetic mutations and maternal risk factors, including poorly controlled diabetes, intake of retinoic acid, phenylketonuria, alcohol abuse, poor nutrition during pregnancy, and viral illness such as rubella. […] Chromosomal abnormalities most commonly linked to TOF include trisomy 21 (Down syndrome), 22q11 microdeletions (DiGeorge syndrome), and JAG1/NOTCH2 gene mutations (Alagille syndrome). Previous studies have shown that a chromosomal abnormality is present in roughly 30% of patients with TOF, with 22q11 microdeletions accounting for 16% of cases.

• #42 Tetralogy of Fallot – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK513288/

  The remaining 20% to 25% of patients with TOF have an associated syndrome or a chromosomal abnormality, with the most frequent being trisomy 21 (ie, Down syndrome) and the 22q11.2 deletion syndromes. […] Thus, genetic testing is currently recommended in fetuses with TOF to assess for the 22q11.2 microdeletion, especially since outcomes are worse than in those who do not carry the microdeletion. […] The ductus arteriosus is usually absent, and approximately 50% have a right-sided aortic arch. […] Surgical repair requires unifocalization of the many aortopulmonary collaterals, which can be quite challenging. […] The clinical manifestations of patients with TOF and absent pulmonary valves depend on the severity of respiratory distress, ranging from those with no respiratory distress to those with severe respiratory distress due to trachea and main stem bronchi compression by the massive pulmonary artery branches. […] The degree of obstructive airway disease among these patients varies markedly. […] The prognosis of these patients is also affected by the need for pulmonary valve replacement due to progressive pulmonary insufficiency, which places them at risk of bacterial endocarditis.

• #43 Genetic insights into Tetralogy of Fallot: Oh MYH(6) | Pediatric Research

  https://www.nature.com/articles/s41390-024-03195-3

  Of these, Tetralogy of Fallot (ToF) is the result of an anterior and cephalad deviation of the infundibular septum during cardiogenesis, resulting in ventricular septal defect (VSD; lack of septation of the left and right ventricle); overriding aorta (malalignment of the aorta over the intraventricular septum); pulmonary stenosis (PS; narrowing of the right ventricular outflow tract to the pulmonary arteries), and right ventricular hypertrophy (RVH; thickening of the right ventricular wall secondary to right ventricular hypertension). […] Despite its clinical significance, the genetic mechanisms underlying ToF are not completely clear. […] The authors hypothesized that MYH6 may also play a role in the pathogenesis of ToF, given previous associations noted between this particular CHD and mutations in myogenic heart progenitors.

• #44 Genetic insights into Tetralogy of Fallot: Oh MYH(6) | Pediatric Research

  https://www.nature.com/articles/s41390-024-03195-3

  This study opens a new research focus area on the MYH6 promoter region and makes a case to add MYH6 as a causative ToF gene for genetic screening. […] However, a complete understanding of the genetic mechanisms underlying ToF remains elusive, with approximately 80% of cases being non-syndromic and without a known etiology. […] The study by Zuo et al. is the first that focuses specifically on the role of MYH6 in the pathogenesis of ToF. […] By continuing to uncover candidate genes, missing links in what is likely a complex multifactorial pathway with multiple gene-gene interactions underlying ToF can continue to be elucidated and, ultimately, lead to new therapeutic interventions in the clinical setting.

• #45 Tetralogy of Fallot – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK513288/

  The physiological process surrounding these hypercyanotic episodes is yet to be fully understood but appears to involve a decrease in systemic vascular resistance or an increase in pulmonary vascular resistance. […] Patients with TOF and pulmonary atresia are usually cyanotic in the newborn period, with worsening cyanosis as the ductus arteriosus closes. […] The clinical presentation will also depend on the associated cardiovascular anomalies in roughly 40% of patients with TOF. […] Approximately 75% to 80% of TOF cases are nonsyndromic, meaning that the patient has an isolated cardiac defect. […] In conotruncal malformations, suppression of developmental networks such as the NOTCH and WNT pathways during early embryogenesis produces malfunction of downstream regulatory pathways that lead to faulty structural cardiac development.

• #46 Tetralogy of Fallot | Pediatric Echocardiography

  https://pedecho.org/library/chd/tetralogy-fallot

  Tetralogy of Fallot (TOF) encompasses a spectrum of cardiac defects that stem from anterocephalad deviation of the outlet septum, along with abnormal septoparietal trabeculations which contribute to right ventricular infundibular narrowing. This leads to the four well-known components of TOF: […] Approximately 25% of patients with TOF have a chromosomal abnormality, most commonly 22q11 deletion (DiGeorge) syndrome followed by trisomy 21. As with other conotruncal defects, TOF is associated with abnormal neural crest cell migration; 22q11 deletion is seen in about 20% of patients with TOF with pulmonary stenosis and in more than 40% of patients with TOF with pulmonary atresia. […] Dynamic obstruction occurs as the hypertrophied RV infundibular muscle contracts, causing further RVOT obstruction over the course of systole.

• #47 Tetralogy of Fallot: Risks and Management in Adulthood – Clinical Advisor

  https://www.clinicaladvisor.com/features/tetralogy-of-fallot-in-adulthood/

  It has been proposed that during development, a portion of the ventricular septum is displaced anteriorly into the right ventricular outflow tract (RVOT); however, the exact etiology of TOF is not fully understood. The most common associations are genetic mutations and maternal risk factors, including poorly controlled diabetes, intake of retinoic acid, phenylketonuria, alcohol abuse, poor nutrition during pregnancy, and viral illness such as rubella. […] Chromosomal abnormalities most commonly linked to TOF include trisomy 21 (Down syndrome), 22q11 microdeletions (DiGeorge syndrome), and JAG1/NOTCH2 gene mutations (Alagille syndrome). Previous studies have shown that a chromosomal abnormality is present in roughly 30% of patients with TOF, with 22q11 microdeletions accounting for 16% of cases.

• #48 Tetralogy of Fallot | Orphanet Journal of Rare Diseases | Full Text

  https://ojrd.biomedcentral.com/articles/10.1186/1750-1172-4-2

  Tetralogy of Fallot is a congenital cardiac malformation that consists of an interventricular communication, also known as a ventricular septal defect, obstruction of the right ventricular outflow tract, override of the ventricular septum by the aortic root, and right ventricular hypertrophy. […] The aetiology is multifactorial, but reported associations include untreated maternal diabetes, phenylketonuria, and intake of retinoic acid. […] The embryological basis of the combination of lesions is antero-cephalad deviation of the developing outlet ventricular septum, or its fibrous remnant should this septum fail to muscularise. […] The combination of the deviated outlet septum and the hypertrophied septoparietal trabeculations produce the characteristic right ventricular outflow tract obstruction of tetralogy of Fallot.

• #49 Tetralogy of Fallot | Orphanet Journal of Rare Diseases | Full Text

  https://ojrd.biomedcentral.com/articles/10.1186/1750-1172-4-2

  The antero-cephalad deviation of the outlet septum, coupled with an anomalous relationship to the septoparietal trabeculations, results in a narrowing of the subpulmonary outflow tract. […] The obstruction to flow into the lungs often extends beyond the subpulmonary outflow tract itself. […] The chronic volume load sustained by the overriding aorta is implicated in the dilation of the aortic root noted in adults with tetralogy of Fallot. […] The risk of recurrence in families is 3%.

• #50 Tetralogy of Fallot – BHF

  https://www.bhf.org.uk/informationsupport/conditions/tetralogy-of-fallot

  An over-riding aorta is when your aorta grows in the wrong place and sits above the VSD. Blood with a lack of oxygen in it is sent around your body which can cause your skin and lips to turn blue or grey (cyanosis). […] Tetralogy of Fallot is a type of congenital heart disease, which means its something youre born with. Many people with tetralogy of Fallot live a normal life, but over time it can cause other problems with your heart like heart failure and high blood pressure. […] A common problem for people with repaired tetralogy of Fallot is a leaky heart valve between the heart and lungs. This is known as pulmonary regurgitation, where your pulmonary valve does not close properly. This lets blood leak back into your heart instead of forwards into your lungs. […] A leaky heart valve puts extra strain on your heart, making it work harder. This can cause symptoms like feeling more tired and out of breath. Over time, it can increase your risk of having a heart attack, stroke and other heart conditions. […] If you have repaired tetralogy of Fallot, you may be at risk of having other issues like: abnormal heart rhythms, blood leakage through your VSD, endocarditis, heart failure.

• #51 Tetralogy of Fallot: Risks and Management in Adulthood – Clinical Advisor

  https://www.clinicaladvisor.com/features/tetralogy-of-fallot-in-adulthood/

  Long-standing pulmonary insufficiency or stenosis progressively leads to a volume-loaded RV or pressure-loaded RV respectively. This causes dilation and hypertrophy of the RV that may ultimately lead to RV heart failure. […] Arrhythmias are also common in patients with rTOF during long-term follow-up. A study of 556 adult patients with rTOF or pulmonary atresia, 43% either had a sustained arrhythmia or arrhythmia intervention. Arrhythmias are usually attributed to low conducting anatomic isthmuses related to both native anatomy and consequences of surgical repair. […] Patients with TOF face a risk of neurodevelopmental impairments preoperatively, intraoperatively, and due to genetic predisposition. Preoperative risk factors include chronic hypoxemia, hypoperfusion, acidosis, and thromboembolic events.

• #52 Repaired tetralogy of Fallot: the roles of cardiovascular magnetic resonance in evaluating pathophysiology and for pulmonary valve replacement decision support | Journal of Cardiovascular Magnetic Resonance | Full Text

  https://jcmr-online.biomedcentral.com/articles/10.1186/1532-429X-13-9

  The common theme that has emerged from the literature on risk stratification of major adverse events (death, ventricular tachycardia, and heart failure) late after TOF repair is that there are 3 major categories of outcome predictors: 1) history (syncope, older age at repair); 2) electrophysiological markers (prolonged QRS duration, sustained ventricular tachycardia); and 3) hemodynamic sequelae of severe PR (RV dilatation, ventricular dysfunction, and regional wall motion abnormalities). […] There is strong evidence that PVR is highly effective in eliminating or greatly reducing PR. […] Although conclusive confirmation that PVR improves survival late after TOF repair is still lacking, a growing body of evidence has emerged during the last decade supporting the rationale for the procedure.

• #53 Tetralogy of Fallot | Orphanet Journal of Rare Diseases | Full Text

  https://ojrd.biomedcentral.com/articles/10.1186/1750-1172-4-2

  The antero-cephalad deviation of the outlet septum, coupled with an anomalous relationship to the septoparietal trabeculations, results in a narrowing of the subpulmonary outflow tract. […] The obstruction to flow into the lungs often extends beyond the subpulmonary outflow tract itself. […] The chronic volume load sustained by the overriding aorta is implicated in the dilation of the aortic root noted in adults with tetralogy of Fallot. […] The risk of recurrence in families is 3%.

• #54 Tetralogy of Fallot: Risks and Management in Adulthood – Clinical Advisor

  https://www.clinicaladvisor.com/features/tetralogy-of-fallot-in-adulthood/

  Long-standing pulmonary insufficiency or stenosis progressively leads to a volume-loaded RV or pressure-loaded RV respectively. This causes dilation and hypertrophy of the RV that may ultimately lead to RV heart failure. […] Arrhythmias are also common in patients with rTOF during long-term follow-up. A study of 556 adult patients with rTOF or pulmonary atresia, 43% either had a sustained arrhythmia or arrhythmia intervention. Arrhythmias are usually attributed to low conducting anatomic isthmuses related to both native anatomy and consequences of surgical repair. […] Patients with TOF face a risk of neurodevelopmental impairments preoperatively, intraoperatively, and due to genetic predisposition. Preoperative risk factors include chronic hypoxemia, hypoperfusion, acidosis, and thromboembolic events.

• #55 Tetralogy of Fallot (TOF) in Adults Clinical Presentation: History, Physical Examination

  https://emedicine.medscape.com/article/2035949-clinical

  The mechanism is thought to include spasm of the infundibular septum, which acutely worsens the right ventricular (RV) outflow tract obstruction. […] Symptoms generally progress secondary to hypertrophy of the infundibular septum. Worsening of the RV outflow tract obstruction leads to RV hypertrophy, increased right-to-left shunting, and systemic hypoxemia. […] Even after surgery it is important to understand that despite the curative approach to surgery, it is simply a long-term palliative procedure. The surgery only corrects the anatomic abnormality; it does not address the cause and does not prevent the ongoing anatomic changes in the RV and pulmonary vessels. Hence, sooner or later, most patients with corrective surgery will present with some type of symptom related to dysfunction of the RV and RV outflow tract obstruction.

• #56 The Pathogenesis of Tetralogy of Fallot

  https://pmc.ncbi.nlm.nih.gov/articles/PMC1904044/

  A pathogenetic mechanism for the formation of tetralogy of Fallot is postulated. […] The surgically unaltered hearts from 77 cases of tetralogy of Fallot were examined, and measurements made of certain morphologic features. A malformed, stenotic pulmonary valve was found in most all cases and accounts for a divided ejection stream. Infundibular stenosis is shown to be a postnatally acquired, progressive lesion. […] The detailed anatomic features of the heart and great vessels in tetralogy of Fallot are explained as a response of the developing heart and great vessels to the abnormal blood flow pattern of a divided right ventricular ejection stream. This pathogenetic mechanism, compared to previously proposed hypotheses, appears better able to account for the malformation complex of tetralogy of Fallot.

• #57 Tetralogy of Fallot pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Tetralogy_of_Fallot_pathophysiology

  Tetralogy of Fallot is a congenital heart lesion characterized by a constellation of four morphologic abnormalities present in the newborn heart. It is understood that tetralogy of fallot is the result of improper positioning of the outlet septum. […] In Tetralogy of Fallot, proper ventricular septation is perturbed by anterocephalad displacement of the outlet septum relative to the septomarginal trabecula. The direct consequence of this misalignment is an overriding aortic orifice and a ventricular septal defect, resulting in an intracardiac right to left shunt of blood. […] Together, the displacement of the outlet septum coupled with the hypertrophic arrangement of the septoparietal trabeculae account for the three anatomical cardinal defects in Tetralogy of Fallot – aortic dextroposition, interventricular communication (VSD), and pulmonary stenosis. The fourth defect – right ventricular hypertrophy – is a hemodynamic consequence of these three morphologic changes, as the right ventricle physiologically adapts to the increased resistance of a stenotic pulmonary trunk.

• #58

  https://step2.medbullets.com/cardiovascular/120002/tetralogy-of-fallot

  Clinical definition: a congenital cardiac defect caused by anterosuperior displacement of the infundibular septum characterized by PROV […] Pathogenesis: pulmonary stenosis causes right ventricular outflow obstruction and causes right-to-left shunting […] the right-to-left shunt across the VSD causes cyanosis […] squatting or knee-chest position can increase preload and systemic vascular resistance, alleviating the right-to-left shunting caused by right ventricular outflow obstruction and relieving the cyanosis.

• #59 Tetralogy of Fallot

  https://mobile.fpnotebook.com/CV/Peds/TtrlgyOfFlt.htm

  Right to left shunt is the key mechanism of Tetralogy of Fallot […] Right outflow obstruction leads to pulmonary vascular resistance greater than Systemic Vascular Resistance […] Blood easily shunts across the Ventricular Septal Defect which re-circulates de-oxygenated blood […] Tet Spells occur from increased right sided pressures, or decreased left sided pressures.

• #60 Tetralogy of Fallot

  https://mobile.fpnotebook.com/CV/Peds/TtrlgyOfFlt.htm

  Right to left shunt is the key mechanism of Tetralogy of Fallot […] Right outflow obstruction leads to pulmonary vascular resistance greater than Systemic Vascular Resistance […] Blood easily shunts across the Ventricular Septal Defect which re-circulates de-oxygenated blood […] Tet Spells occur from increased right sided pressures, or decreased left sided pressures.

• #61 Tetralogy of Fallot – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/tetralogy-of-fallot/symptoms-causes/syc-20353477

  Tetralogy of Fallot is a combination of four heart changes present at birth. There is a hole in the heart called a ventricular septal defect. There also is a narrowing of the pulmonary valve or other area along the pathway between the heart and lungs. Narrowing of the pulmonary valve is called pulmonary stenosis. The body’s main artery, called the aorta, is misplaced. The lower right heart chamber wall is thickened, a condition called right ventricular hypertrophy. Tetralogy of Fallot changes how blood flows through the heart and to the rest of the body. […] These heart problems affect the structure of the heart. The condition causes altered blood flow through the heart and to the rest of the body. […] The optimum treatment approach remains controversial, but in general, complete repair is advised in the first three to six months of life. Importantly, the application of the modified BlalockTaussig shunt as a palliative procedure is performed much less commonly in the current era. The surgical goal is complete repair, which consists of ventricular septal defect closure and relief of right ventricular outflow tract obstruction, which is ideally performed with preservation of pulmonary valve function.

Zobacz więcej