Congenital heart disease can be classified as cyanotic and acyanotic.
CYANOTIC CONGENITAL CARDIOPATHIES
They are cardiac malformations that, due to the nature of their anatomical alterations, present a short-circuit from right to left with a mixture of venous and arterial blood and production of cyanosis.
Of the cyanotic congenital heart disease, the tetralogy of Fallot, the complete transposition of the great vessels, the tricuspid atresia and the common trunk arteriosus will be studied.
Tetralogy of Fallot
Tetralogy of Fallot (TF) constitutes 6% of congenital heart disease. This malformation is characterized by the association of four cardiac abnormalities: ventricular septal defect (VSD), stenosis of the right ventricular outflow tract (infundibulovalvular stenosis), aortic dextroposition, and right ventricular hypertrophy.
The fundamental embryological alteration of TF is the asymmetric truncoconal partition, which results in a stenosis of the right ventricular outflow tract, or infundibular stenosis, whose magnitude governs the severity of the condition.
When there is a truncated conal alteration, an interventricular communication is formed, because the ventricular septum cannot coincide with the septal septum of the arterial trunk. The other alterations are by addition. Thus, aortic dextroposition is due to the asymmetric partition of the arterial trunk, with a large and small pulmonary aorta. Therefore, the larger aorta remains on the ventricular communication, riding on the septum and on both ventricles, the more to the right the greater the pulmonary narrowing. Right ventricular hypertrophy is the consequence of ventricular work governed by resistance from pulmonary stenosis and systemic aortic resistance.
TF makes up a whole hemodynamic spectrum, at the most severe end of which is pulmonary atresia with aorta as the only way out of the RV and LV to the other end of a poorly closed infundibular stenosis with pulmonary resistance less than systemic resistance and Therefore, a left-to-right shunt due to ventricular septal defect, without cyanosis, known as pink TF.
Hemodynamics of tetralogy of Fallot. In TF with severe infundibular stenosis, the returning venous blood, upon reaching the RV, faces two resistances, one major, or infundibular, and another minor, or peripheral aortic resistance (aortic diastolic pressure).
For this reason, a significant volume of venous blood is directed towards the aorta, mixing with the arterial blood, expelled by the LV.
The more severe the infundibular stenosis, the greater the venous volume towards the aorta and vice versa. The venous flow that manages to cross the infundibular stenosis constitutes the volume of arterialized blood that returns to the left chambers. Cyanosis is the obligatory consequence of this short circuit.
As there is a significant VSD although the RV faces marked resistance, in infundibular stenosis there is an escape route through the VSD.
In circumstances in which the infundibular stenosis is very severe and the flow to the lung is scarce through this route, the development of collateral circulation occurs through the bronchial artery system and, sometimes, through the ductus arteriosus (ductus arteriosus) .
Symptoms and signs
Cyanosis . The appearance of cyanosis is related to the severity of the malformation. When seen in the first days after birth, TF is very severe.
In general, children with TF are born acyanotic, and in the first weeks of life they develop cyanosis with the effort of crying, suckling or defecating. After the second or third month of life, cyanosis becomes permanent and universal. The early appearance of cyanosis is a manifestation of poor prognosis.
Breathlessness . Always accompany these children. It is produced by pulmonary hypoflux and arterial unsaturation. The magnitude of dyspnea is related to the severity of the malformation.
During the evolution, dyspnoic crises with intense and abrupt increase in cyanosis may occur. Spontaneously or caused by some effort (crying, defecation, etc.), a catecholamine secretion occurs that causes infundibular spasm and absence of blood flow to the lung, which causes intense paroxysmal dyspnea and cyanosis. The crisis can subside in a few minutes or be prolonged causing metabolic acidosis and ending the life of the patient. Once a crisis has occurred, it will tend to repeat itself.
Growth and gait retardation . Arterial unsaturation causes a great delay in body growth and in learning to walk.
Digital hypocratism . After a few months of life, the nail convexity begins to be observed, with cyanosis of the subungual bed, which causes increase in the capillaries of the extremities of the fingers and toes, with hypertrophy of the soft tissues and bone, forming the finger cyanotic drumstick or hypochralic finger.
Squat position . When children learn to walk, exertion causes them ischemic dyspnea, which is counteracted with squatting. With this maneuver, they increase aortic pressure and venous return, thereby succeeding in forcing the infundibular stenosis and improving pulmonary flow. In paroxysmal dyspnea and cyanosis crises, adopting this position can improve these symptoms.
Radial pulse and venous pulse . The radial pulse is always of normal characteristics and the venous pulse also, and there is no increased amplitude "a" wave.
Precordial examination . The left ventricular impulse has the characteristics of the right ventricle and is located in the 4th left intercostal space, hemiclavicular line.
A systolic frequency may be palpated in the subpulmonary area, and there is a low parasternal positive systolic beat (sagittal beat). The suprasternal aortic beat is palpable, an important finding in childhood.
Auscultation varies according to the severity of the stenosis. If it is mild, there is a holosystolic regurgitation murmur, mesocardial, through VSD, and a pulmonary or subpulmonary ejection systolic murmur through pulmonary stenosis. In the most severe one, with pulmonary atresia, there are no murmurs, and finally, in the very severe ones with a dominant right-to-left shunt, a protomesosystolic ejection, subpulmonary murmur (third and fourth left intercostal spaces) and an aortic protosystolic click are heard. due to increased ejected flow into the aorta and dilation of the aortic vessel.
When collateral circulation is present, systolic or systodiastolic murmurs spread over the chest are heard.
Electrocardiogram . It shows signs of right ventricular enlargement, with a vertical electrical axis at approximately +130 ", directed downward and to the right in the frontal plane. The P wave is not tall and acuminate and its width is normal.
The QRS in DL and AVL is of the rS type, and in D2, D3 and AVF of the qR type. In the horizontal plane, they appear with diphasic R wave (- +) and from V2 to V6 RS with positive T. The positive T from V2 to V4 is very important, showing systomic pressures in the RV, and the same is the difference between LV and V2.
Radiology . It does not show an exaggerated cardiac enlargement. The lower left arch is rounded and separated from the hemidiaphragm (heart in clog or ram's trunk). The pulmonary median arch is concave, the aorta large, and there are signs of pulmonary hypoflux. In oblique, the left cavities can be normal or of diminished size.
Laboratory . The magnitude of the hematocrit elevation is an important sign of the degree of arterial unsaturation.
Echocardiography . It clearly shows the anatomical findings described and is a very useful non-invasive technique for diagnosis.
Cardiac catheterization and angiocardiography . These invasive techniques allow us to know exactly the anatomy of the malformation and assess its severity. They should always be done.
Complete transposition of the great vessels
The complete transposition of the great vessels (TCGV) consists in that the aorta is located in front of the pulmonary artery, arising from the right ventricle, while the pulmonary artery does so from the left ventricle.
In order for the circuits to be connected, it is necessary to have intercavitary communications, a CIA or a CIV. When the latter exists, the pulmonary artery may or may not present a pulmonary stenosis. If there is a pulmonary stenosis, the picture is clinically the same as that of tetralogy of Fallot. GCT without pulmonary stenosis will be described.
When the ASD is large, or when there is an ASD plus VSD, the venous blood that reaches the right atrium goes to the RV and from there to the aorta and pulmonary artery. The pulmonary return flow to the left atrium makes an inverse course. Therefore, in cases of large intercavitary communications, there is pulmonary hyperflow with arterial unsaturation due to mixing of venoarterial blood in the aorta. This combination of cyanosis with pulmonary hyperflow is characteristic of TCGV. Pulmonary hyperflow causes early pulmonary hypertension. In addition, changing flows to both sides cause cardiac enlargement and ventricular failure.
The incidence of TCGV is 8% of frozen heart disease. It is more frequent in men than in women in a ratio of 4 to 1. It is rare in the first child, and there may be a family history of diabetes.
Cyanosis is observed from the moment of birth, the intensity of which depends on pulmonary flow. When there is moderate cyanosis, cardiac enlargement is considerable due to the existing pulmonary hyperflow, and signs of heart failure, dyspnea, hepatomegaly, edema, etc. appear. When cyanosis is severe, there are no signs of congestive heart failure, but anoxic distress is significant.
Growth can be done quite well with acceptable weight gain.
The diagnosis is based on the presence of: a) cyanosis from birth; b) signs of congestive heart failure; c) considerable cardiac enlargement; d) auscultation of non-distinctive systolic murmurs; e) second aortic A2 and pulmonary P2 sounds located in areas other than normal; f) right-hand overload electrocardiogram, and g) radiology with cardiac enlargement, ovoid-shaped heart and pulmonary hyperflow.
These children should be studied for cardiac catheterization early, before they develop congestive heart failure or pulmonary hypertension.
Tricuspid atresia (TA) is a more infrequent congenital cyandic heart disease, comprising 1% of all congenital heart disease.
It consists of the lack of development of the tricuspid valve, which is replaced by a fibrous tissue in the form of a membrane that forms the lower floor of the right atrium. The AD communicates with the Al through a patent foramen ovale, or, more commonly, an ASD. The LV is large and hypertrophic and the RV is small and communicated with the anterior through VSD. The aorta and pulmonary artery may be in normal position (pulmonary artery originating from the RV and LV aorta) or in transposition, and in turn, the pulmonary artery may be atresic, with infundibular stenosis or normal. There are six anatomical varieties of the malformation and in each one of them the hemodynamic conditions vary.
A form of TA with pulmonary stenosis (with or without arterial transposition) will be described as a characteristic of this condition.
Symptoms and signs
The cyanosis is intense and quite early, depending on the flow to the lungs. The statutory development is poor. Paroxysmal crises of dyspnea and cyanosis are common and indicate a great severity of the condition. Over time they develop digital clubbing.
On physical examination the venous pulse may show a large a wave. The precordial examination reveals a hyperdynamic and outwardly displaced left ventricular impulse, of a muscular type, well palpable in the left lateral decubitus position.
There is a negative sign of great value: the absence of a positive lower precordial systolic beat (sagittal beat).
A cyanotic heart disease without palpatory signs of right hypertrophy is suggestive of AT. The pulmonary artery is not palpable either. Auscultation varies according to the anatomical type of TA; An ejection systolic murmur of pulmonary stenosis, a protosystolic aortic ejection sound, and a regurgitation murmur from VSD may be found.
Electrocardiogram . He presents a deviation of the electrical axis to the left with signs of left hypertrophy and high and acuminate P waves. This combination, in a newborn, is pathognomonic for AT.
Radiology . In the anatomical form that motivates this description, the frontal radiograph shows a salience of the left lower arch, with a concave pulmonary mid-arch, a dilated aorta and an enlarged right atrium. The pulmonary fields are of pulmonary hyperflow. In the left anterior oblique, the lack of RV development and the salience of the LV arch are observed, configuring a fairly typical image.
Echocardiography . It is useful for the non-invasive diagnosis of the condition.
Cardiac catheterization and angiocardiography . They are essential to confirm the suspected diagnosis, determine the anatomical type of TA and indicate the therapy to follow.
Arterial trunk comun
The common trunk arteriosus (CT) is a malformation in which a single large vessel exits the heart base with a single lunate valve. The CT scan is located above a defect in the interventricular septum, receiving flow from both ventricles and giving rise to the coronary circulation and the systemic and pulmonary circulation.
There are four varieties of CT, depending on how the circulation to the lung originates. In type I, there is a short pulmonary trunk emerging from the CT scan; in types II and III, the right and left pulmonary branches arise directly from the CT scan (from behind in II and from the lateral wall in III); in type IV, there are no pulmonary branches and blood reaches the lungs through the bronchial arteries.
From a clinical point of view, the important thing is the size of the pulmonary branches, since when they are of good caliber there is a pulmonary hyperflow and the lung receives blood at systemic pressure. If there are no pulmonary branches or if they are narrow, there will be pulmonary hypoflux. In the case of a CT with pulmonary hyperflow, pulmonary hyperresistance is its consequence, whereas the accompanying of a CT with pulmonary hypoflux are great cyanosis and arterial unsaturation. It appears equally in both sexes.
Dyspnea, recurrent bronchitis, heart failure, and poor physical development characterize CT with pulmonary hyperflow, and there are signs of right ventricular hypertrophy. A very audible ejection protosystolic click is detected on auscultation. There are not very intense ejection murmurs, continuous murmurs originating in the pulmonary branches with a second intense, wide and single sound.
The ECG shows a right ventricular overload and the X-ray shows a heart in the shape of a clog or a ram's tube, with a concave left middle arch and a large single vessel, with signs of pulmonary hyperflow or hypoflux.
In cases with pulmonary hyperflow, the development of pulmonary hyperresistance is rapid and congestive heart failure can present earlier. When there is hypoflux, cyanosis is severe and survival is very short.
The interatrial septum defect puts two systems in communication that offer different resistance to the arrival of blood. This difference in resistance is determined by the different compliance of the two ventricles.
When the child is born, the pulmonary resistance is similar to the systemic one, but as the days go by, and in general before six months, it decreases significantly; This results in less work for the RV, with the consequent decrease in the thickness of its wall and thus increase in its complacency.
This normal fact, in the presence of an atrial septal defect (ASD), is the determinant of the shunt, since part of the LA content will be emptied, through the RA, into the RV, since it offers less resistance than the LV . The RV is thus overloaded during its diastole as it must accept more volume than normal, and then it dilates. This greater diastolic volume is easily expelled into the low-resistance pulmonary circuit, without generating an increase in pressure, since its compliance is very great. The pulmonary hyperflow drains into the LA, which, apparently, will suffer a volume overload; However, this is not the case, since it has a double escape route: the normal one, through the mitral valve, and the one from the septal defect, which communicates it with a low resistance circuit.
A flow greater than normal will never pass through the mitral valve; therefore, both the LV and the aorta are protected and do not suffer any type of overload.
In short, the CIA communicates circuits of different resistance and this difference will ultimately be what will determine the magnitude of the blood flow from left to right.
This circumstance will influence the course of the disease. Under normal conditions, the resistance difference between the systemic and pulmonary circuits is maintained; This will lead to a gradual increase in the volumetric overload of the RV, which, very slowly, over the years, will deteriorate. However, in approximately 10% of children with this disease, the pulmonary arterioles react with a constriction that causes the resistance to rise, a phenomenon that is progressive and that can exceed systemic values. Thus, a new type of RV overload is generated, which hypertrophies to overcome the barrier imposed by pulmonary resistance. The end result is a decrease in your compliance, thereby increasing your resistance to filling and thus making atrial emptying more difficult. When the RV,
Symptoms and signs
The evolution of this disease is extremely slow and with few symptoms. In general, the diagnostic suspicion will arise in children during a casual physical examination or by looking at a chest x-ray.
The most frequent symptom is palpitations , but more than 60% of patients present the first symptoms after the age of 30 and in general they are those determined by RV failure.
It is the objective signs that usually allow the diagnosis.
The general inspection does not provide special data. On inspection of the precordium, due to RV volumetric overload, left parasternal systolic impulses are observed; the same happens in the lung area. The posteroanterior beat will be only weakly positive since there is no true RV hypertrophy, since it is a pure diastolic overload. The left ventricular impulse is diffuse because it corresponds to the right ventricle.
The first sound is usually hyperphonetic in the tricuspid area since the tricuspid travel is wide, since the beginning of systole finds it in the position of maximum opening.
The second noise must be considered as the most important element to reach the diagnosis; characteristically is permanently unfoldedand said unfolding is wide and practically fixed, that is, it does not vary with respiratory movements. The amplitude of the splitting is due to the combination of a delayed activation and the prolongation of its expulsive period. The fixity of the unfolding is due to the following; inspiration normally produces an increase in the filling of the right chambers, thereby prolonging the emptying of the right ventricle and thus delaying the pulmonary component of the second sound. In ASD, the increase in venous return to the RA produced by inspiration determines a decrease in the passage of blood from the LA, and thus both ventricles receive the same volume, regardless of respiratory movements.
The second noise is also essential to follow the evolution of pulmonary resistance, because if it increases, the intensity of its second component will concomitantly.
The large flow through the tricuspid valve can cause a severe diastolic murmur with characteristics of pain, similar to that of organic tricuspid stenosis; however, there will be no opening click as both valve structure and mobility are normal.
At the level of the pulmonary valve an early ejection systolic murmur will be generated, due to the hyperflow that passes through said valve. This auscultatory phenomenon can be considered constant in ASD.
The chest radiograph shows hypervolemic lung fields but without signs of venocapillary hypertension. The cardiac silhouette is enlarged, mainly at the expense of the RV, while the LA is characteristically normal. The AD is usually moderately enlarged. The pulmonary artery is protruding since it is increased by hyperflow and, in addition, by the hourly rotation of the heart determined by the right ventricular overload.
If pulmonary resistance increases, the radiological image will be modified, leaving the pulmonary fields hyperclear with great dilation of the pulmonary artery and its branches.
In the ECG , the presence of conduction disorders of the branches of the His bundle can be considered typical, in the form of complete block of the right branch; its absence raises serious doubts about the diagnosis of an ASD, since 98% of the cases present it. Atrial fibrillation is common.
The natural history of this disease is slow, and the individual usually tolerates it very well. However, when the diagnosis has been reached, it must be studied hemodynamically to confirm it.
When there are signs that show an evolution towards pulmonary hyperresistance, it is necessary to act quickly since at the moment in which the pulmonary resistance equals the systemic resistance, it is beyond any possibility of surgical resolution.
Ventricular septal defect (VSD) is characterized by the presence of a solution of continuity in the septum that separates the two ventricles, establishing communication between two chambers of different resistance and generating different pressures.
It is the most common congenital heart defect, accounting for 18% of all these conditions.
Anatomically it can vary both in its location and its size. In relation to the location, and simplifying a lot, the defect can be considered to be in the membranous area of the septum or in the muscular area. Regarding the size, it can be from point-shaped to practically encompassing the entire Septem, leaving both chambers working as one.
Under normal conditions, pulmonary vascular resistance is approximately one-fourth to one-sixth that of systemic.
In the VSD, the pumps of both systems come into contact, thus generating a totally anomalous situation. The LV, in its emptying, finds an escape route towards the RV and through this towards the pulmonary circuit, which offers it a much lower resistance. This fact already explains why, when pulmonary resistance is normal, the RV does not suffer a great overload, since in essence it acts as a passageway.
Thus a greater quantity of blood reaches the pulmonary vascular bed. Within certain limits, pulmonary hyperflow does not determine hypertension in said circuit and does determine a decrease in vascular resistance; This fact is explained by the expansion of the functional capacity due to the passive dilation of the arterioles and the opening of new channels that under normal conditions are functionally closed. If these physiological limits are exceeded, increases in flow produce an increase in pulmonary arteriolar pressure (ie, precapillary pressure). This hypertension determined by hyperflow is called hyperkinetic hypertension.
But the hyperflow at the pulmonary arteriolar level continues in the capillary and venous beds, reaching Al and overloading this chamber volumetrically. This increased blood volume reaches the LV through a mitral valve that, being normal, will become relatively stenotic, which will force the LA to hypertrophy and generate greater pressure. This increased pressure in the LA will be transmitted to the pulmonary venocapillary bed since they function as a single chamber; This fact is what totally differentiates VSD from CIA, in which venocapillary hypertension does not occur, with all the consequences that it entails, as will be pointed out later.
Al excess blood bursts into the LV, generating a volume overload during diastole, to which it adapts by dilating.
It is a purely volumetric overload, since its emptying is facilitated by the existence of communication with a low resistance circuit.
A normal volume of blood is expelled through the aortic valve, so the size of the aorta is normal; however, it may appear slight hypoplasia in relation to the rest of the left chambers that are dilated.
From the above, it is obvious that the magnitude of hemodynamic dilations depends directly on two factors: 1) the size of the VSD, and 2) the relationship between systemic resistance and pulmonary resistance. In fact, it is also these two factors that determine the evolution of heart disease.
The size of the VSD can vary and in some children it closes spontaneously; however, it is lung resistance that normally produces changes in the course of the disease.
Shortly after the child is born, the resistance of the pulmonary arterioles decreases, so the passage of blood from the LV to the RV increases, reaching its maximum when the pulmonary resistance gradually increases, and may even exceed the systemic values.
Secondary to this increase in pulmonary resistance, the emptying of the RV is made difficult, which thus suffers a pressure overload and hypertrophy and, more importantly, the passage of blood from the LV to the RV is hindered, thus decreasing the short circuit. When pulmonary resistance equals systemic resistance, both ventricular chambers have the same pressure and the shunt disappears. If the pulmonary resistance exceeds the systemic one, there will be a "passage of blood from the RV to the LV and the aorta; at this moment the child will become cyanotic and will be beyond any possibility of correcting the interventricular defect.
This evolutionary picture is more frequent in large VSDs and is generally completed in the first decade of life.
Symptoms and signs
Symptoms. Unlike ASD, VSD presents a picture characterized by lush symptoms caused by pulmonary venocapillary hypertension, dependent on the size of the defect and the relationship between pulmonary and systemic resistance. The more symptoms are as follows:
Stop feeding . The physical effort produced by the suction will produce an increase in venocapillary hypertension, which will force the child to interrupt it. It is in everything similar to the dysmea that the child will present when he is older.
Repetitive bronchial phenomena . Sustained venocapillary hypertension leads to bronchospasms that mimic acute bronchitis. There are data that allow the differentiation between primary bronchitis and bronchitic phenomena secondary to pulmonary venocapillary hypertension. In the first case, in general, they are preceded by infectious processes of the upper airways, begin with hyperthermia and are more frequent in the cold seasons.
The phenomena dependent on heart disease, on the other hand, do not present this characteristic; however, in its evolution, infections can be added since the congestive lung offers less resistance to bacterial aggression than the normal one. The pulmonary congestion dependent on pulmonary hypertension will only be seen when treating the insufficiency of the left chambers that gives rise to it.
Increased sweating . Venocapillary hypertension reduces evaporation through the pulmonary alveoli, thereby affecting one of the most important mechanisms of temperature regulation; in these circumstances sweating increases as a compensatory mechanism.
If IC is very important, the symptoms of venocapillary hypertension, which at its greatest exponent is lung edema, are added to the signs of right chamber insufficiency; the child will thus present a global cardiac influence, with hepatomegaly and edema
Signs. The physical examination will vary depending on the characteristics of the VSD and the status of pulmonary resistance. The picture of a moderate VSD with normal pulmonary resistance will first be described.
The general inspection shows a child with good development or slightly underdevelopment for his ---> age, of normal coloration and slightly tachynetic, but whose respiratory rate increases disproportionately with exercise.
Inspection of the neck is negative, as well as palpation of the carotid beat. In the suprasternal fossa the aorta is not palpable, an important finding for the differential diagnosis with the patent ductus arteriosus.
Inspection of the precordium shows systolic impulses in the area of the impingement.
On palpation, the left ventricular impulse is moderately displaced to the left and down, due to LV dilation. It is a dynamic shock, characteristic of volume overload, and the ventricular fast-fill wave (whose vibrations give rise to the third noise) can often be palpated.
Since pulmonary resistance is normal, there will be no significant RV overload, so a positive anteroposterior beat is not found.
In the lower right parasternal area, a systolic frequency is palpable, corresponding to the rapid passage of blood from the LV to the RV.
On auscultation, the first noise in the mitral area is normal or moderately hyperphonetic, since the onset of ventricular systole finds the mitral valve in its position of maximum opening due to the hyperflow coming from the LA. The second noise in the lung area is permanently unfolded but with respiratory mobility; the pulmonary component is normal or moderately increased in intensity.
A fundamental finding is the presence of a third noise in the mitral area ; represents the fast ventricular filling and will be greater the greater the short circuit.
A regurgitant systolic murmur occupying the entire systole is heard in the lower left parasternal area; It is born with the first sound and reaches the second, and on occasions it can exceed the aortic components of the latter, since the passage of blood to the RV can continue even after the closure of the aortic sigmoid; This is due to the low resistance offered by the pulmonary circuit.
In the mitral area, a diastolic rumbling sound can be heard , caused by increased blood passing through the mitral valve, which is relatively stenotic; it always continues at a third noise, and COD el are fundamental data to evaluate the magnitude of the short circuit, since the greater the flow, the greater the intensity of the diastolic phenomena.
The physical signs described change gradually when pulmonary resistance increases.
When the pulmonary resistance equals the systemic, cyanosis appears with exertion, which will become permanent when the pulmonary pressure exceeds the systemic one.
The presence of a positive posteroanterior beat will be verified due to RV hypertrophy, and the vibrations corresponding to the second sound in the lung area will be clearly palpated. On the contrary, the systolic frequency disappears and the ventricular fast full wave is no longer palpable at the level of the left ventricular impulse, since the hyperflow disappears.
The first sound in the tricuspid area is hyperphonetic and the second is sharply increased in intensity in its pulmonary component, which approaches the aortic, tending to become single. The regurgitation murmur is diminished or disappears, as well as the diastolic phenomena due to the hyperflow that reached the LV. As in all important pulmonary arterial hypertension, a vascular ejection sound appears that is produced by the tension to which the pulmonary artery is subjected.
The ECG shows overload of the left chambers with slight right ventricular overload, which will increase as pulmonary resistance rises.
The chest radiograph shows pulmonary hypervolemia with signs of venocapillary hypertension. The cardiac silhouette is enlarged, mainly at the expense of the left chambers. The aorta is normal, which is characteristic.
As pulmonary resistance increases, the signs of venocapillary hypertension decrease and the peripheral areas clear.
Patent ductus arteriosus
The ductus arteriosus is a normal intrauterine vessel that connects the left branch of the pulmonary artery with the descending thoracic aorta below the origin of the subclavian artery. The duct closes functionally in the first days of life, and it can be considered pathological if it remains patent after three months. It can have a diameter of millimeters, up to a centimeter, and also variable length.
Hemodynamically it is similar to an interventricular communication with some variants that are specified.
The defect puts the systemic circuit in communication with the pulmonary circuit, and due to the difference in resistance between the two, there is a passage of blood to the pulmonary bed throughout the cardiac cycle.
Hyperflow, as in VSD, produces an overload at the pulmonary vascular level and after LA; since the mitral valve is normal, a relative stenosis is generated with the consequent increase in pressure in the LA and therefore in the venocapillary bed.
Increased filling of the LV causes dilation of this cavity due to diastolic overload. The LV empties entirely into the aorta and this fact determines the dilation of said vessel, marking a difference with VSD. Aortic dilation is only seen in its ascending portion, while the descending portion is normal since excess blood passes into the lung through the ductus.
The pulmonary arteries can react by increasing their resistance; When it exceeds the systemic, the shunt is reversed and cyanosis appears.
Symptoms and signs
The symptoms of these children is directly related to the magnitude of pulmonary venocapillary hypertension and has the same expression as in VSD: a) interruption of breastfeeding , b) repeated bronchial phenomena , and c) increased sweating .
If the defect is very large, the symptoms of failure of the left chambers are added to the right congestive phenomena, leading to global heart failure.
Palpation of the pulse makes a difference from VSD; it is broader due to a drop in aortic diastolic pressure due to the escape of blood into the pulmonary circuit. In the suprasternal hollow the aorta is palpable, a fact to which great importance is assigned for the differential diagnosis.
Inspection of the precordium, as well as palpation of the left ventricular impulse, are similar to those of VSD, since in both cases there is LV diastolic overload. Also in this pathology, if pulmonary arteriolar hyperresistance occurs, the presence of a positive posteroantcrior beat due to right ventricular hypertrophy will become evident.
A thrill is palpated in the so-called left ductus or subclavicular area, above the pulmonary area. This thrill is continuous, encompassing both systole and diastole.
On auscultation, the first sound in the mitral area is normal or moderately hyperphonetic; the second noise in the lung area is permanently split but not fixed , and the intensity of the second component depends on the pressure in the pulmonary circuit. A third noise is heard in the mitral area and eventually a diastolic pain, which, as in VSD, depends on the magnitude of the shunt from left to right.
The pathognomonic element is the presence in the ductus area of a continuous, increasing-decreasing murmur that rides on the second noise.
Another very important auscultatory element, although not constantly observed, is the presence of so-called "multiple clicks", "take-off noises" or "multiple crackles", which are superimposed on the systolic component of the murmur and which can be considered as pathognomonic manifestations. of the semiology of the ductus arteriosus.
When pulmonary arteriolar hyper-resistance develops, variations in the auscultatory semiology arise, there is a decrease in the duration of the murmur, firstly at the expense of its diastolic component, and if the resistances are equal, it can disappear; Instead, "multiple clicks" persist, ranking them even more. The pulmonary component of the second sound increases in intensity and tends to approach the aortic component, and the splitting disappears. Audible diastolic phenomena in the mitral area are absent since hyperflow disappears.
The radiological findings are similar to those seen in VSD but with one fundamental difference: in the ductus arteriosus, the aorta is characteristically enlarged in its ascending portion.
The electrocardiogram, as in ventricular communication, shows signs of left chamber overload, the right ventricle becoming evident when pulmonary resistance increases.