Ped.cardiology

Lecture notes; prepared by Dr.J.A.RASHID

Evaluation of CVS diseases includes special focussing in the history & physical examination on e.g cyanosis, breathlessness, orthopnea, feeding difficulty, sweating, squatting, chest pain & looking for clubbing, edema, chest deformity, engorged neck veins & hepatomegaly.

Checking peripheral pulses & B.P. both of the upper & lower limbs is important.

On heart examination particular attention must be directed towards precordial bulging, hyperdynamic precordium, thrills& murmurs regarding their timing, intensity, area & transmission.

C.V. invstigations; required to make a precise conclusion include:

ECG, H-Xray, ECHO& catheterization.

In general a heart disease is possibly present when one of the following major or 2 of the minor criteria are present:

Major: S.M (More than Gr. 3), D.M, C.C., C.H.F.

Minor: S.M (less than Gr. 3), abnormal 2 nd H.S. , abnormal ECG, abnormal heart size on x-ray& abnormal B.P.

Cardiothoracic ratio is the ratio of maximum cardiac & the maximum width of the chest in a mid-inspiration PA film with the patient in the upright position.

A ratio of more than 55 during infancy & more than 50 after infancy is considered enlargement of the heart.

The Rt. Border of the H. consists from above downward from aorta, pul. artery & Rt.atrium. Lt. border consists of aorta, pul.artery & left ventricle.

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Pulmonary vascularity is seen on x-ray as intra pulmonary shadows from H. outwards.

Increased vascularity indicates Lt. to Rt. while decreased vascularity Rt. to Lt. shunts.

Pediatric ECG principles:

A 14 lead ECG including V3R & V4R is essential as these later leads help in determining RVH.

Tall,spiked & narrow p wave(more than 2.5mv) in lead 2 indicates

RAH.

Wide p wave (more than 0.12sec in lead 2) indicates LAH.

RVH is indicated on ECG by:

+ve T wave in V3R

R in V1+ S in V6= more than11mm

Q wave is pathological when it is more than 0.04 sec & more than 1/3 rd of R amplitude.

LVH is indicated on ECG by:

R in V5/V6 + S in V1=more than 45 mm

R in V5/V6=more than35mm

ST depression & T inversion in left precordial leads

QT interval varies with HR & prolonged QT interval may be a genetically determined condition& cause sudden death or is acquired by some drugs.

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ST segment elevation occurs in pericarditis & its depression occurs in digoxin toxicity, myocardial damage in aberrant coronary origin.

T wave inversion occurs in all forms of carditis.

T wave is tented in hyperkalemia.

Flattening of T wave & even its inversion in addition to generalized low voltage occur in hypothyroidism.

Echocardiography is a very important tool in the evaluation of both congenital& acquired heart diseases.

M-mode echo shows the motion of H. valves, septal movement , vegitations.

Doppler echo shows flow instead of morphology in cardiac or vascular chambers.

Color Doppler helps better evaluation of intracardiac shunts &valvular insufficiency.

Transesophageal echo is more sensitive especially in showing vegitations of endocarditis.MRI may be another helpful mode of staging cardiac diseases. Cardiac catheterization is specially required when information about echo & MRI are yet limited & the patient is a serious candidate of heart surgery. Pressure & O2 saturation of different heart chambers & great vessels can be measured & contrast can be injected when required.

Complications of cardiac catheterization: Hypothermia, Acidosis, Blood loss, Arrhythmia& Cardiac perforation.

Interventional catheterization helps in offering nonsurgical treatment of certain cardiac lesions like: valvular PS, PDA, AS, secundum ASD

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FETAL CIRCULATION:

Gas exchange of the fetus depends on placental circulation, whereas after delivery neonates depend on their lungs for the purpose of gas exchange.

The umblical vein (UV) takes oxygenated blood from placenta to the fetus. Most of the umblical venous blood shunts through the ductus venosus(DV) to the IVC, the smaller proportion goes through the liver.

IVC blood is composed of blood coming from: Hepatic veins, Umbilical veins, Blood from lower extremities & kidneys.

The IVC blood enters the Rt.atrium & then about 1/3 rd of this blood passes through foramen ovale to the Lt.atrium, the remaining 2/3 rd of the IVC blood mixes with the venous return through superior vena cava & enter the Rt. Ventricle.

A very small volume of blood returns from the rudimentary lungs & with the IVC blood in the Lt.atrium passes to the Lt.ventricle then through aorta to the coronaries, head, neck & upper limbs.

The venous return from sup.ven.cava streams mainly (95%) to the Rt. Ventricle then through pulmonary artery, from where a very small amount supply lungs while most of the pulmonary artery blood passes through DA to the descending aorta to the lower parts of the body.

Postnatal changes in the circulation: Sudden expansion of lungs with the 1st few breathes causes a fall in pulmonary vascular resistance & pulmonary artery pressure & an increased flow through pulmonary trunk.

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The pressure relations between aorta & pul.artery are reversed so that changing PA to aorta to aorta to PA shunt through PDA.

The increased O2 saturation after birth causes DA musculature to constrict & ultimately close the ductus at 10-21days in full terms.

2. Closure of DV by 7 th day after birth, due to sudden cessation of placental circulation.

3.Foramen ovale: increase of Lt. atrial pressure to become higher than the Rt.atrial pressure results in this closure which is initially functional soon after birth, anatomical closure takes months to a year.

Congenital heart diseases (CHD)

Heart is the 1st functioning organ in the embryo. 90% of CHD can be attributed to genetic & environmental factors interaction. (multifactorial) & only 10% are due to teratogenic or specific genetic causes, these specific causes include:

Chromosomal anomalies e.g Down & Turner syndrome.

Drugs as lithium…….Ebstein anomaly

Congenital rubella…….PDA

Maternal SLE…….congenital heart block

The prevalence rate of CHD in most parts of the world is about 1%.

Risk for a child to be affected if a sib or one of the parents is affected is 2-10% (affected mother has the greatest effect). The risk increases to 25% if 2 other children have CHD.

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CHD can be classified in to 2 groups ; acyanotic & cyanotic. Mild desaturation may be missed & can give an impression of being acyanotic while the child in fact has cyanotic CHD.

In general the acyanotic group covers 2/3 rd while the cyanotic group 1/3rd of all CHD.

A third group (obstructive CHD) is sometimes added to cyanotic & acyanotic groups.

The following are some of CHD:

A.acyanotic( Lt. to Rt. Shunt):

VSD 25%, ASD 10%, PDA 5%

They form 40% of all CHD

B.cyanotic (Rt. To Lt. Shunt):

TOF, TGA, truncus arteriosus, tricuspid atresia, total anomalous pulmonary venous drainage, hypoplastic left heart syndrome, Ebstein anomaly.

C.obstructive CHD:

Coarctation of aorta, vascular rings, pulmonary stenosis, anomalous origin of coronary arteries, congenital mitral stenosis, congenital aortic stenosis.

D.dextrocardia

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Short notes on the relatively common forms of CHD

Ventricular septal defect (VSD)

VSD is the most common form of CHD in infants & children.

VSD usually occurs in isolation but it may be part of more complex heart lesions such as TOF.

Anatomically VSD may be perimembranous in 80% of cases or muscular in the remaining. VSD results in Lt. to Rt. Shunt during systole (as Lt. vent.pressure exceeds the Rt. during systole) that’s why the murmur is pansystolic &best heard close to Lt.sternal border (3 rd, 4th & 5 th intercostals spaces) & its usually accompanied by a thrill.

A functional diastolic murmur is also heard, caused by increased blood flow across normal mitral valve.

Small sized VSD (less than 0.5cm) causes only a limited Lt. to Rt. Shunt & is usually asymptomatic while larger ones although initially also cause a limited shunt (due to high pulmonary vascular resistance), however with gradual reduction of this resistance during neonatal period the shunt magnitude increases & the condition becomes symptomatic.

With passage of time pulmonary vascular obstructive disease begins to develop. When the Rt. & the Lt. pressure becomes equal (1:1 ratio) the shunt becomes bidirectional. At this stage the child becomes cyanotic (Eisenmenger complex or syndrome).

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Clinically:

Small VSD of less than 0.5cm & when the pulmonary to systemic blood flow ratio is less than 1.75/1 is usually asymptomatic.

Moderate & large VSD cause recurrent chest infection, C.C.F., failure to thrive & exertional dyspnea.

Diagnosis:

Is clinically highly suspected, heart x-ray may show enlarged size with prominent pulmonary conus & increased pulmonary vascularity.

:

Normal in small VSD

LVH in moderate VSD

Biventricular hypertrophy in large VSD

Echocardiography confirms the diagnosis.

Cardiac catheterization may be indicated in selected cases.

Complications:

Infective endocarditis (VSD is the commonest congenital lesion complicated by infective endocarditis, 1/500 VSD patient /year)

Eisenmenger syndrome.

C.C.F

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Management:

Small asymptomatic cases are just followed up until spontaneous closure occurs.

Medical treatment of C.C.F, repeated chest infection, prevention & treatment of anemia & infective endocarditis are necessary.

Surgery is indicated in the following situations, best to be done after 2 years:

CCF during infancy which can not be controlled medically, even in infants.

Large Lt. to Rt. Shunt (pulmonary flow is twice systemic flow or more).

In presence of associated pulmonary stenosis, pulmonary artery hypertension or aortic regurgitation.

Appearances of Eisenmenger complex contraindicates surgery.

Complications of VSD surgery:

Death in 1-2 %

Rt.BBB when the Rt.ventricle is opened (VSD is usually closed using Dacron patch through Rt. Atrium)

Reopened or residual VSD

Atrial septal defect (ASD)

The ostium secondum( higher) type is 10 times more common than the ostium primum ( lower) type. This later form may be associated with mitral & or tricuspid valve defects. The primum type is also called endocardial cushion defect which is common in Down syndrome.

The degree of Lt. to Rt. Shunt across the defect which may make P: S of more than 2:1 depends on:

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1. Size of the defect.

2. Relative compliance of both Rt. & Lt. Ventricles.

3. Relative vascular resistance of both pulmonary & vascular circulation.

ASD is rarely symptomatic during childhood. Older children & adults may have breathlessness, recurrent chest infection, failure to grow, and bulging precordium due to Rt. Ventricular enlargement.

Auscultation reveals an ejection systolic murmur along upper sternal border on the left side + fixed splitting of the P2.

In normal children during inspiration increased venous return leads to increased RV volume which leads to delayed pulmonary valve closure & split P2 during inspiration.

In presence of ASD the RV volume is constantly increased causing delay pulmonary valve closure throughout both respiratory phases, this leads to fixed splitting of P2.

X-ray shows cardiomegaly, pulmonary plethora, and prominent pulmonary artery.

Echo confirms the diagnosis.

Catheterization is rarely required; it shows the O2 content of Rt. Atrial blood to be much more than that of superior vena cava.

Both infective endocarditis & Eisenmenger complex are very rare in ASD. Rarely ASD may spontaneously close.

Surgical treatment is preferable at 2-5 years of age.

Transcatheter device closure has recently become a common way of treatment.

Device treatment or surgical closure are used for all symptomatic patients & even for those asymptomatics with P: S of more than 2:1.

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Small ASD with minimal shunt can be left without treatment.

Patent ductus arteiosus(PDA):

A patent DA which is essential for the maintenance of fetal circulation,, undergoes spontaneous closure both functionally & anatomically shortly after birth. Failure of this closure results in PDA. PDA, unlike most of the other CHD, occurs most often as isolated defect & is twice more common in females. Lt. to Rt. Shunt occurs both during systole & diastole as pressure gradient is present throughout cardiac cycle between aorta & pulmonary artery, provided the pulmonary artery pressure is normal. This results in the characteristic continuous murmur (continuous machinery murmur), at the upper left sternal border.

Large PDA with excessive left to right shunt may also result in a mitral diastolic murmur, wide pulse pressure (more than30 mmHg).

PDA murmur may be only systolic in the following situations:

Infant of less than 6 months as pulmonary pressure is still high.

Presence of HF.

Development of pulmonary hypertension.

Small PDA.

Children with moderate-severe PDA are likely to have recurrent chest infection, growth failure & develop HF.

X-ray shows cardiomegaly, prominent pulmonary artery & increased pulmonary vascularity.

ECG shows LVH

Echo confirms the diagnosis.

Management:

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1. Medical:

Indomethacine; 0.1mg/kg 12 hourly, for 3 doses during the 1 st 10 days of neonatal life, especially in preterms.

Treatment of CCF & recurrent respiratory tract infection.

Prophylactic against endocarditis.

2. Surgical:

Ligation & excision after 3 months of age & before 4 years.

Catheter intervention by:

*Rashkind umbrella closure.

*Coil occlusion.

*Amplatzer device.

Coarctation of the aorta (COA)

COA is a narrowing of the aortic arch just below the origin of the left subclavian artery, causing diminished flow from proximal to distal aorta. 50% are associated with bicuspid aortic valve. It is a common finding in Turner syndrome. Mild forms of COA may cause no symptoms & are accidentally detected.

Features of moderate-severe forms include:

Absent, feeble or delayed femoral pulses (normally femoral pulse precedes radial, in COA femoral pulse is delayed until after the radial).

Murmur at the left upper back (highly suggestive of COA).

Increased BP in the Rt. upper & decreased in the lower limbs.

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In severe pre-ductal type, CCF may occur during neonatal period with possibly differential cyanosis (pink upper while cyanosed lower parts of the body).

In post-ductal type, manifestations which develop during later childhood include fatigue, cramps, claudication, headache, weakness & exertional dyspnea

.Occasionally there may be overgrowth of the upper parts of the body.

Chest x-ray shows cardiomegaly, notching ribs caused by intercostals collaterals & “E” sign on barium swallow.

Echo gives some indirect evidence of COA.

Catheterization & angiocardiography shows severity, location & collaterals.

Management:

General:

Restriction of strenuous exercise.

Treatment of CCF.

Prostaglandin E1 to keep DA open.

Antibiotic prophylaxis of bacterial endocarditis.

Dopamine to maximize renal perfusion.

Surgical: best done at 3-5 years.

Resection of the coarctated area & end to end anastomosis.

There is 50% chance of recurrence.

Balloon angioplasty instead of surgery & for recurrent cases after surgery.

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Tetralogy of Fallot (TOF)

TOF is the most common cyanotic CHD.

The 4 components of which are:

1. VSD.

2. Pulmonary stenosis (mostly infundibular & rarely valvular)

3. RVH (concentric without cardiomegaly)

4. Over riding of the septal defect by the aorta (due to deviation of the origin of aorta to the right.)

Notes:

*in presence of an additional ASD its called pentalogy of Fallot

*when the PS is not severe enough to cause Rt. to Lt. shunt, cyanosis is absent & the condition is called pink Fallot.

* The 2 most vital components which determine the severity are PS & VSD (especially the PS)

Clinical picture:

Central cyanosis is rarely present since birth (except when the PS is extremely severe or there is pulmonary atresia), generally it appears after few weeks or months due to:

1. Open PDA during early life

2. Progressive infundibular hypertrophy

3. Increased O2 demand by the active child

The cyanosis of TOF depends on the interplay between PS on one hand & the systemic vascular resistance on the other hand, factors which increase the former(crying, tachycardia) or decrease the later(exercise,

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vasodilatation, volume depletion) result in or increase the already present cyanosis.

On the other hand factors that increase systemic vascular resistance or decrease RV out let obstruction (volume overload, systemic hypertension, valsalva maneuver, or bradycardia) improve the cyanosis.

The typical murmur of TOF is a load, short systolic (without thrill) along the Lt. sternal border in the 3 rd space due to PS.

Clubbing appears from late infancy.

Dyspnea on exertion is a characteristic picture of TOF & the affected children will learn to adopt squatting position to relieve breathlessness( by decreasing venous return on one hand & increasing systemic vascular resistance on the other hand.

Chest x-ray is characteristic & shows:

Small boot-shaped heart (Coeur en sabot) with the end of the boot turned up above the diaphragm due to RVH.

Concave pulmonary artery area.

25% have right aortic arch.

Oligemic (poorly vascularised lungs)

ECG shows RVH.

Blood studies show polycythemia & a high hematocrit.

Echo & cardiac catheterization with selective angiocardiography will prove confirmation.

Complications of TOF:

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1. Cerebral thrombosis (venous or arterial): especially in young children during dehydration states.

2. Cerebral abscess: usually affects children over 2 years, characterized by fever, signs of raised ICP & localized neurological signs. Micro organisms which may be of the anaerobic group by-pass the filtering lung mechanism.

Penicillin+metronidazole must be the initial antibiotics.

3.infective endocarditis: must always be suspected (as in most of the other forms of CHD) in presence of prolong fever, new murmur , HF, splenomegaly, microscopic hematuria, various embolic phenomina & vegitations on Echo.

4.paroxysmal hypoxic spell (hypercyanotic or “tet” spell):

More common in younger children, characterized by sudden deepening of cyanosis & decreased murmur intensity with alteration of consciousness & hyperpnoea as a result of severe hypoxia & acidosis.

Tet- spells are usually triggered by exertion as feeding, straining & crying.

Management ofTet spell includes:

Comfort the child & put in knee-chest position

Humidified O2

Morphine 0.1-0.2mg/kg s.c.

IV fluid & induce over expansion of circulatory volume.

Blood if anemic.

NaHCO3

Propranolol 0.1-0.2 mg/kg I.V.

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Increase systemic vascular resistance by methoxamine or phenylephrine.

Take an appointment for surgical repair

Prevention of further attacks by oral propranolol & correction of anemia with iron. Blockade of B-receptors in vessels allows unopposed alpha-1 activity(vasoconstriction)

5. Growth retardation

6. Bleeding diathesis & hemoptysis: probably caused by hypoxic platelet dysfunction & pulmonary vessels thrombosis.

Treatment of TOF: General:

Correction of iron def. anemia

Partial exchange when Hct. Exceeds 65% using plasma or N.saline;

Exchang volume= 85 X wt X (actual Hct- desired Hct)

……………………………………………………

Actual Hct.

Prophylaxis against infective endocarditis.

Propranolol prophylaxis for spells.

Neonates with severe TOF need prostaglandin E1 infusion ( before , during & for a short period after surgery ).

Refer for surgery as soon as Tet- spell starts.

2. Surgical:

A. palliative by creating a systemic-to-pulmonary shunt:

Modified Blalock-Taussing operation : by anastomosing subclavian artery to pulmonary artery.

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Potts operation: aorta to pulmonary artery.

Waterson operation: ascending aorta to Rt. Pulmonary artery.

B. Total correction: by closing VSD & relief of pulmonary obstruction, carried out between 6month & 2 years.

Prognosis:

*without surgery, rarely survive beyond 20 years.

*with surgery the patient lives a normal life.

Transposition of the great arteries (TGA)

This is the most important cause of central cyanosis almost since or shortly after birth.

TGA is the main cause of mortality from CHD during the 1 st year of life.

TGA is 3 times more common in boys & the affected baby is usually LFD.

In TGA the aorta arises from Rt. Ventricle & the main pulmonary artery from Lt. ventricle, making both circulations (systemic & pulmonary) be in parallel rather than in series. Characteristically TGA results in early Eisenmenger physiology.

Adequate saturation can only be achieved by shunting blood from one circulation to the other through PFO, VSD, ASD or PDA.

TGA+PDA & Eisenmenger syndrome have differential cyanosis (upper cyanosed & lower pink), since blood of higher saturation from the P.A. is shunted into the descending aorta.

Enlarged heart & plethoric lungs.

ECG shows RVH & coften “P” pulmonale.

ECHO is helpful.

Catheterization & selective angiocardiography confirms the diagnosis

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Treatment:

*medical: PGE1 & anti failure.

*Ballon atrial septostomy early in the neonatal period.

*definitive surgical repair by: (better to be done during early infancy)

Jatenes switch operation: pulmonary artery & aorta are transected, then the aorta to pulmonary stump & pulmonary artery to aortic stump + coronary artery shifting to aorta.

Mustard or Senning atrial switch operation: by redirecting pulmonary venous blood to the Rt. Ventricle & the systemic venous blood to the Lt. ventricle.

Total anomalous pulmonary venous drainage (TAPVD)

TAPVD is a rare (less than 1% of all CHD) which as its name indicates means draining of all pulmonary veins to the Rt. Atrium instead of the Lt. atrium, either directly or indirectly ( through SVC, Lt. innominate vein, coronary sinus or even through portal vein).

Most affected babies will have CCF with or without cyanosis.

X-ray shows the typical figure of “8” or snowman configuration, cardiomegaly & plethoric lung fields.

Echo & pulmonary angiography will confirm the diagnosis.

PGE1, antifailure & surgery as soon as the diagnosis is confirmed, as the great majority will die during early infancy without surgical treatment.

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Tricuspid atresia (TA)

TA means congenital absence of tricuspid valve making systemic venous return to enter the Lt. atrium through an ASD or patent foramen ovale.

Therefore there will be complete mixing of both systemic & pulmonary venous blood in the Lt. atrium. Presence of a VSD is essential for blood to go through the pulmonary artery to the lungs. If VSD is absent, PDA is essential.

The larger the VSD & the greater the pulmonary blood flow, the lesser the degree of cyanosis which appears soon after birth.

In 30% of TA there is associated TGA.

In absence of VSD there is usually no murmur while in it presence there will be VSD like murmur.

ECG characteristically shows Rt. Atrial dilatation & Lt. ventricular hypertrophy.

Clinically TA simulates TOF except for:

Earlier onset of cyanosis

Pansystolic murmur

Prominent jugular pulsation

Hepatomegaly & presystolic pulsation.

X-ray commonly shows oligemic lungs (plethora in presence of TGA)

Echo & cath. are confirmatory.

Treatment:

*Medical; like for TOF

*Surgical aims at directing the systemic venous return to the pulmonary artery by:

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1. SVC to Rt.pulmonary artery (Glenn shunt).

2. IVC to pulmonary artery (Fontan shunt) at 2-6 years.

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