Peds33+34_Cyanotic and Acyanotic Heart Diseases

33-34

Cyanotic & Acyanotic Heart Diseases

Eyad Amouri Shakeeb & Sakher 21 / 12 / 2009

ACYANOTIC HEART DISEASES

Fetal Circulation: The differences between Fetal and infant circulation: 1- Cardiac output in infants is the total cardiac output rather than the left and the right ventricle . so we talk about combined cardiac outout because the fetus dosen’t use his lungs, the blood that supposed to go to the lungs goes through Ductus Artereosus to the Left Ventricle then to the Descending Aorta. 2- The organ that is responsible for O2 saturation is the placenta not the lungs. 3- There are 3 comminucations in the fetal circulation: -

PDA: which directs blood away from the lungs. (pulmonary to Aortic).

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Patent Foramen Ovale: between right and left atrium, to direct blood from right to the left.

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Ductus Venousus: Comminucation between umbilical vein with rich oxygenation across hepatic vein to the Inferior Vena Cava. 

All these communications disappears after birth.

After birh, the circulation becomes 2 circulations; the pulmonary and systemic.

We classify Conginital Heart Diseases into 2 major groups; Shunt and Non shunt lesions: SHUNT LESIONS: Shunt means: the blood is foing into a circulation that it is not supposed to go to. Systemic blood is RED: goes to the body. Pulmonary blood is BLUE: goes to the lungs. In Shunt lesions, there is mixing between bleu and red blood. NON SHUNT LESIONS: - is classified into obstructive and Regurgitation lesions. -

Obstructive is usually congenital while Regur. Is usually acquired, like mitral, aortic regurg. Which cause volume overload in the heart.

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Aortic stenosis is the most common example on obstructive lesions.

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Shunt lesions could also be classified to: 

Left to right shunt.

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Right to left shunt (Cyanotic heart disease).

Left to Right shunt: -

Types: ASD, VSD, PDA.

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Red blood goes to the lung.

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Ineffective circulationbecause the blood is fully oxygenated, when it goes back to the lungs, all what it will do is just volume overload at the lungs.

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Doesn’t cause cyanosis because there is Left to Right shunt not Right to Left, so the shunt doesn’t affect the blood oxygenation.

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VSD and PDA is the same story.

Aas we said, the amount of blood that goes to the lungs is called ineffective blood flow. The effective blood flow is calculated by the ratio between the pulmonary blood flow (the amount that goes to the lungs) and the systemic blood flow (the amount that goes to the body).

Physiology of ASD: -

It’s usually asymptomatic.

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Cardiac output is normal because the heart will do his best to compensate normal Cardiac output, but it will increase the pulmonary flow.

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L. atrium, R. atrium, R. ventricle, and Pulmonary artery will complain of dilation, while the L. ventricle will not.

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There will be fixed splitting of S2.

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There will be also R. ventricle heave because of dilation.

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There is also Ejection murmer.

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X- Ray will show R. artrial dilation lateral X- Ray will show R. ventricle against the sternum because of dilation.

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There will be no shifting of the apex.

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Some patients may present as “Failure to thrive”.

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If the patient has Asthma and ASD, it will make symptoms of Asthma become worsen.

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Congestive Heart Failure will not happen.

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In older children they may complain of dyspnea on exercise Page 2 of 10

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Pulmonary Hypertension almost never happens because it is a low pressure shunt.

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Some older children may present with SVT, Artrial or Ventricular tachycardia.

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Pneumonia presents with more sever symptoms because of increased pulmonary blood flow, but there is no relation between ASD and Pneumonia progression.

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Upon ECG:

() Signs of Right axis deviation. () Signs of Right arterial dilation. () Signs of Right ventricular dilation. () Arrythmias.

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Upon X- Ray: () Plethoric lungs. (increase in vascular markings). () Cardiomegaly due to Right atrial dilation.

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Echocardiogram is the diagnostic tool.

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There is no management except surgical methods (closure of the defect).

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There are no medications that could treat ASD, and there is no need for Bacterial Endocarditis prophylaxis.

Physiology of VSD: -

Is the communication between Right and Left ventricles.

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Red blood goes to the Right ventricle.

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Types: () Perimembranous (most common). We know from anatomy that ventricle’s septum is mostly muscular except a small part underneath the

aortic valve is membranous. nd

() Membranous (2  common), which is a muscular defect in any part of ventricular septum. () Anlet (3rd common), or AV canal. Its common in patients with trisomy 21. () Subpulmonary defect which is the rarest type. -

Newborns are asymptomatic because the pulmonary vascular resistance is high when they are born and this takes about 4-8 weeks to become as adults, So, the left to right shunt is minimal in the newborn age.

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If the VSD is large enough, then there will be an increase in the pulmonary blood flow and this will cause left ventricular and left arterial dilation, and eventually Heart Failure because when the left ventricle become dilated according to “frank- starling law” when it becomes dilated to an extent the

heart contractility will drop down and the heart could not compensate anymore, so the cardiac output will become aggressively low,,, as a result, Heart Failure could occur. Page 3 of 10

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Babies with Heart Failure present with symptoms that differs from thes in adults. Symptoms are : RS symptoms, Excessive sweating, and the most important one is weight loss.

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Heart murmers may not be present in 1qst day of life because –as we saidthe pressure is almost equal in both ventricles b ecause the pulmonary pressure is high. So, there is no turbulence in the blood flow across VSD, but murmers usually appear after the age of 1 day, and its of pansystolic murmer type.

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Definitely, the apex beat will be shifted due to Left ventricular hypertrophy.

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If we have a small VSD, we’ll have a pansystolic murmer, but we call it short

systolic murmer because it disappears before s2, . -

We’ll have also a loud S2, because there is pulmonary hypertension and that

will cause loud P2 not A2. -

We may hear also a disystolic murmer because of excessive flow across a normal mitral valve.

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S3 gallop presents with patients with Heart Failure.

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Asymptomatic (small) VSD doesn’t need any intervention, it closes

spontaneously. -

For symptomatic VSD, we eliminate the symptoms or close it by surgical intervention.

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In VSD also we don’t give patients SBE prophylaxis.

Coaroctation of the Aorta: -

Non- shunt obstructive lesions.

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The obstruction is in the distal part of the aortic arch just distal to the left subclavian artery and because there is obstruction there, the heart starts to pump at a high pressure in order to perfuse the lower extremities. So there will be a hypertension in the upper extremities and normal or low pressure in the lower extremity there will be left jugular hypertrophy.

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The apex beat will be dilatedand eventually there will be a collateral blood flow across the area of obstruction.

Physiology of PDA: -

Communication between the aorta and the pulmonary artery.

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Causes some changes like VSD.

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The only difference between PDA and VSD is i n the Blood pressure, it causes wide pulse pressure.

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CYANOTIC HEART DISEASES Cyanosis: it’s bluish discoloration of the lips, it happens when there is clinically significant amount of deoxygenated hemoglobin and usually that’s about 3-4 g/dl in order to see the cyanosis by your eys, so

if the Hb of individual is 15, and you need 5g of deoxy Hb, so the saturation should be less than 70% in order to see cyanosis. Cyanosis is a clinical sign seen by your eyes. Desaturation is not a clinical sign seen by your eyes, its actually calculated by saturation that you measure, So not every hypoxemic patient may present with cyanosis. Especially in children, they usually have Hb of 10, So they need to be 60% desaturated in order to see the cyanosis. The major cause of cyanosis in children is pulmonary causes. Pulmonary causes: 1- Air way diseases: pneumonia, asthma, foreign body.(anything prevent the air getting in). 2- Hypoventilation: central causes. 3- Intrapulmonary circulation: the blue blood crosses to the red blood areas. Cardiac causes of cyanosis is always secondary to intracardiac shunt which is the blue blood going to red blood areas this is the cause of cardiac cyanosis. The other rare causes like methmoglobinemia. Cardiac causes: 1- Right to left shunt: blue blood going to the left side of circulation, so this is pure right to left shunt. Eg: TOF. 2- Mixing: both blue and red blood mix together in a chambers and there is distributed to the lungs and the body. 3- Recirculation: the whole red blood going to right side of circulation(pulmonary artery), and the blue blood going to the left side of circulation(to the body). That what happens in TGA. The left ventricle pumping blood to the lungs and the right ventricle pumping blood to the body, so the pulmonary arterial circulation is 100% saturated, and the systemic arterial circulation is 50%. Page 5 of 10

So Cyanotic Heart Diseases: -

To diagnose cyanotic heart diseases, approach should include full history to rule in and out.

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We do also physical examination, and some tests are used to help in diagnosis as Chest radiograph, ECG, and Hyperoxygenation test, but non of them is a diagnostic tool for the lesion itself. BUT the only test that is diagnostic is the Echocardiogram.

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Hyperoxygenation test: is a test performed by giving the patient 100% o2 to overcome the cyanosis, if the patient become well, then he has a respiratory problem, but if not, he has a cardiac problem. Y3NI, we give the patient 100% O2 and take an ABG, if PO2 is more than 250 then usually the cause is respiratory, but if PO2 is less than 150 then the cause is cardiac.

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Cyanotic Heart Diseases are: Tetralogy of Fallot, Transposition of great vessels, Truncus Arteriosus, Total Anomalus, and Tricuspid Atresia.

Tetrology of Fallot -

Components are: 1- VSD. 2- Pulmonary Atresia. 3- Aortic override. 4- Right Ventricular hypertrophy.

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Most common cyanotic heart disease.

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3  most common overall.

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10% of congenital heart diseases.

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Etiology: There is no certain cause of TOF, but it usually presents with some

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syndromes as: Down’s, De Lange, Klippel- Feil, and others.

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Physiology:

() Depends in 2 factors; VSD and Pulmonary artery

obstruction. So if the patient doesn’t have Pulmonary stenosis, then its VSD

not TOF. Y3ni TOF without pulmonary stenosis IS VSD. () Pulmonary stenosis differs from a patient to another, and its progressive with time, Y3ni, at one month of age, it will be moderate, at six months it become severe, Y3ni the patient becomes more cyanotic with time. () There is equal pressure in both ventricles. () Flow depends on the difference between systemic and pulmonic outflow resistance. Page 6 of 10

() None of the chambers will have volume overloadin those patients with TOF. () No cardiomegally. () Upon Chest X- Ray: we will find Oligemic lungs, Right ventricular hypertrophy and heave, and Right axis deviation because of Right ventricular hypertrophy. NOTE: Oligemic lungs look exactly like hyperinflated ones, but the only difference is that in oligemic

lungs there will be normal ribs, in contrast, in hyperinflated lungs the ribs will be more horizontally oriented. () Hypercyanpotic spells: are episodes of intense cyanosis, seen in patient with TOF and other cyanotic heart diseases, and it could be life- threatening, and these spells are indication for the need of surgical intervention. () Sqatting: is when the patient squat (knee to chest position), trying to reduce the cyanosis by angulation and kinking of femoral arteries with increased SVR, decreasing Right to Left shunt.

Hypercyanotic Spells ( TET spells)

Syncope

Morphine

Hypovolemia

 Agitation

Tachycardia

Oxygen  Cyanosis

Knee-chest

Rt Lt shunt  PVR

Fluid

Impaired RV filling

RVOT obstruction

Phenylepherine

 Age

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Chest X- Ray: reveals normal heart size, but an abnormal shape, y3ni the patients will have what is called “boat shaped” heart, and upturned apex, and

there is a concavity in the area of the pulmonary artery. -

Patients are polycythemic , and it is a secondary mechanism to hypoxia.

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If the Hct more than 60% might have symptoms of hyper viscosity syndromes.

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Surgical management is required by closure of VSD.

Transposition of Great Vessels -

The Aorta originates from the R ventricle, and the Pulmonary artery originates from the Left one.

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So the blue and the red blood keep going to the same area. Now, in able to the patient to survive, there must be a comminucation between the two “bloods” at the arterial level. Y3ni usually its essential to these patients to

have ASD or Foramen ovale to survive. -

Presents in about 5-7% of all cyanotic heart diseases.

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50% of the patients may present with VSD but this doesn’t contribute in the

pathology of the disease. -

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Usually the symptoms appear at the 1  few hours of life, so cyanosis at the 1 few hours of life indicates TGV rather than TOF.

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Chest X- Ray shows “egg on sting” heart shape, and there will be also narrow mediastinum because the pulmonary artery and the aorta are “front and back” not “side by side”. 6ab3an these findings appear when it the patient left

untreated. -

So if the patient presents with profound cyanosis at birth, there are number of things that we can do before surgical intervention. One thing is to ensure that is a Right to Left shunt (mixing at the arterial level) and also to ensure that there is a pulmonary blood flow that is blue, so we need blue blood to go to the lungs, and what we do is to keep PDA because the PDA will allow blood from the Aorta to the pulmonary artery and this blood is blue, so that blue blood will go to the lungs and this is the effect of circulation. So when more blood goes to th lungs, more blood is coming to the atrium fully saturated, so the pressure will be more than in the right atrium, and ASD now will function as effective systemic opening, So the blood w ill cross from the left atrium to the right atrium which has red blood that goes to the body. So one is we have to keep the PDA opening by using PGE- @ infusion, if that doesn’t work then we have to do an opening at the arterial septum by a Ballonatrial septostomy.

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Truncus Arteriosus -

Is a common trunk arises from both ventricles. An important point that there is no TA without VSD, but we don’t call it VSD.

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1.2-2.5% of all congenital heart disease

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Generally patients have increased pulmonary blood flow

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Degree of cyanosis is mild and may not be evident clinically until late stage with pulmonary vascular disease

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Upon examination we find Single S2, Ejection click of the abnormal truncal valve , Systolic murmur of truncal valve stenosis if present, Diaastolic murmur of truncal valve insufficiency, and Gallop.

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Upon Chest X-Ray we find: Cardiomegally, increased pulmonary circulation.

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Acute management of TA: is not to give the patient O2 in order to minimize pulmonary blood flow, Give diruitics.

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Surgical management: complete repair with VSD closure and conduit placement between the right ventricle and pulmonary arteries.

Tricuspid Atresia -

Here there is no tricuspid valve, so there is no communication between the right atriem and the right ventricle.

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About 3 % of congenital heart disease

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Usually associated with VSD

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The pulmonary blood flow is dependent on the size of the VSD

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Pulmonary blood flow can be increased or decreased causing variable presenting symptoms

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If there is no VSD ( also called Hypoplastic right ventricle) the pulmonary blood flow is dependent on the PDA

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The presentation of the disease depends on the amount of pulmonary blood flow; if it decreased, then the main presenting symptom is cyanosis. BUT if it increased, the presentation is that of congestive heart failure.

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Chest X-Ray reflects the amount of pulmonary blood flow.

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ECG reveals LEFT AXIS DEVIATION. (V. IMPORTANT).

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Management PBF

Decreased

Increased

PGE-1, and minimal supplemental O2 to maintain ductal patency

No O2  Afterload reduction Diuretics

Total Anomalous Pulmonary Venous Return (TAPVR) -

Rarest cyanotic heart disease.

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Pulmonary veins coming to the left atrium missed the left atrium, the go to the right one to communicate either with abnormal vein or directly to the right atrium, So the pulmonary veins which has red blood goes to the superior vena cava and to right atrium or Inferior vena cava to the right atrium. So all the blood will be mixed in the right atrium, so again this is a complete mixing. The blood can’t go to the left ventricle except through an ASD. So the blood

will be distributed to the circulation through ASD.

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