Cardiovascular System

By Dr.Nuha Abdel Ghaffar

Evaluation
The importance of History and Physical examination cannot be overemphasized. Laboratory evaluation
Eventual treatment or reassurance.

History
Pregnancy:

Maternal illness Drugs Prematurity Presence of cyanosis Respiratory distress

Timing of the first presentation

Perinatal:

Postnatal

Symptoms
Symptoms of CHF are age specific

In infant:
Feeding difficulties Frontal sweating Respiratory distress

In older children:
Exercise intolerance Nocturnal dyspnoea& orthopnoea

Cyanosis Chest pain

Cardiac disease may be a manifestation of a known cong. Malformation or of a generalized disorder affecting the heart as well as other organ systems. So FH of muscular dystrophy or Relatives with CHD. PH of Recurrent attacks of chest infection.

General Physical Examination

Assessment of growth Dysmorphic features. Respiratory distress. Clubbing, JVP Pulse & its character, BP Signs of congestive heart failure. Proper cardiac examination.

Laboratory investigations
Chest X ray: Cardiac size and shape ,lung field ECG Echocardiography Cardiac catheterization.

Fetal Circulation
The right & left ventricles exist in a parallel circuit. Gas & metabolite exchange are provided for by the placenta. The lungs do not provide gas exchange & vessels in the pulmonary circulation are vasoconstricted. 3 structures unique to the fetus :

Ductus venosus Ductus arteriosus Foremen ovale.

Congenital Heart disease

Incidence:

Occurs in 0.5 -0.8% of live birth.

Genetic factors Association with chromosomal abnormalities. Environmental or adverse Maternal conditions (Maternal illness & drugs).

Aetiology: Multifactorial inheritance.

Acynotic CHD
Left to Right shunt Its classified according to the predominant physiologic load they placed on the heart into: 1- Volume overload: -Examples are ASD, VSD, AV canal defect, PDA, Regurigitant valve &cardiomyopathy.

-Communication between the systemic & pulmonary sides of the circulation result in shunting of the fully oxygenated blood back into the lungs.
2- Pressure overload: -Obstruction to normal blood flow -Examples are Pulmonary & aortic stenosis, COA , Tricuspid or Mitral stenosis , Cor triatriatum

VSD
It is the most common malformation accounting for 25% 0f CHD. Definition:

Is a developmental defect of the interventricular septum whereby a communication exists between the cavities of the two ventricles.

Pathophysiology

The major determinants of the size of the leftto- right shunt are:
The physical size of the defect Level of pulmonary vascular resistance

If the size of the defect is small (Maladie de Roger)( <0.5cm2 restrictive type): the cardiac chambers & pulmonary vascular bed are normal.

In large non restrictive defects (>1cm2), there are 2 adverse effects:

Altered hemodynamic leading to :

Left ventricle volume overload LV dilation & hypertrophy with left atrial enlargement Pulmonary over circulation Compromise of systemic cardiac output

Altered pulmonary vascular bed leading to pulmonary hypertension.

Clinical Manifestations
Symptoms & signs relate to the size of the defect & the magnitude of the Lft to Rt shunt. Patients with small defects are asymptomatic Large defects are responsible for dyspnoea ,feeding difficulties, poor growth, profuse sweating , recurrent chest infection, heart failure.

O/E:

Loud lower left parasternal pan systolic murmur frequently accompanied by thrill.

Diagnosis
CXR

Cardiomegaly, prominence of both ventricles &left atrium &pulmonary artery with normal Pul.vascularity
Biventricular hypertrophy

ECG

Echocardiography Cardiac catheteriztion.

Prognosis & complications

Ranged from spontaneous closure to congestive heart failure to death in early infancy depending on the size of the defect Small defect (30-50%) will close spontaneously during the first year of life ,rare in children older than 2 years Large defects rarely close end with pulmonary hypertension Infective endocarditis occur in <2%

Treatment : Surgical correction prophylaxis against infective endocarditis.

ASD
It accounts 6-8% of CHD It can occur in any portion of the atrial septum (Secundum, primum or sinus venosus)

Ostium Secundum defect:

Most common form of ASD Occurs in the region of the fossa ovalis Females outnumbers males 3:1

Pathophysiology

The shunting of oxygenated blood from the left to the right atrium leads to enlargement of the right atrium and ventricle & dilation of the pulmonary artery. Despite the large pulmonary blood flow , the pulmonary arterial pressure remains normal because of the absence of a high pressure communication between the pulmonary &systemic circulation Left ventricle &aorta are normal in size.

Clinical manifestation

Most often asymptomatic Various degree of exercise intolerance Loud first heart sound Fixed splitting of the second heart sound Ejection systolic murmur at left upper sternal border due to increase right ventricular volume

O/E:

Diagnosis

CXR: Rt vent +atria + pulmonary artery enlargement. ECG: Rt axis deviation & Rt bundle branch block Echo Secundum is well tolerated & symptoms appear in the 3rd decade or later. Pulmonary hypertension , atrial dysrythmias & heart failure are late manifestation.

Prognosis:

Infective endocarditis is extremely rare. Surgery for symptomatic &asymptomatic prior to the entry into school.

Treatment

Atrioventricular septal defects (Ostium primum and AV canal defect):

They are grouped together because they represent a spectrum of embryologic abnormality: a deficiency of the Atrioventricular septum.

Ostium primum defect:

Situated in the lower portion of the atrial septum

Continuous atrial & ventricular septal defects with abnormal AV valves. common in Down syndrome

AV canal defect:

Pathophysiology:

Ostium primum is very similar to that of Ostium Secundum AV canal defect :

The shunt is both trans-atrial , trans -ventricular & AV valve sufficiency Pulmonary hypertension is common

Clinical manifestations

Ostium primum may be asymptomatic or have a history of exercise intolerance or recurrent pneumonias AV canal defect present with congestive heart failure, recurrent pneumonias since birth & failure to thrive Fixed splitting of the 2nd heart sound Diastolic murmur at lower left sternal border Apical pan systolic murmur due to mitral insufficiency.

O/E:

Diagnosis:

CXR large heart , pulmonary vascularity ECG: left axis deviation ,Rt vent conduction delay Echo & catheterization If left untreated : death in infancy from congestive heart failure Pulmonary hypertension Surgical correction.

Prognosis & complications

Treatment:

Patent ductus arteriosus

Functional closure of the ductus normally occurs soon after birth Females outnumber males 2:1 It is associated with maternal rubella & common in premature infants

Pathophysiology:

Blood flow through the ductus from the aorta to the Pul. artery . The extend of the shunt depends on the size of the ductus & the ratio of Pul to systemic vascular resistance.

Clinical features

Small PDA : produce no symptoms Large PDA : result in congestive heart failure in infancy Wide pulse pressure with bounding arterial pulses Enlarged heart with apical impulse There is machinery murmur localized to the 2nd left intercostal space accompanied by thrill.

O/E:

Diagnosis:

CXR :prominent Pul. Artery ECG: biventricular hypertrophy Echo& catheterization Small PDA : have a normal live span Large PDA: CHF in early infancy Infective endocarditis ,Pul. Or systemic embolisation & Pul. hypertension Surgical correction

Prognosis & complications

Treatment :

Coarctation of the aorta (COA)

Localized narrowing of the descending aorta . May occur at any point but more commonly 98% just below the origin of the left subclavian artery at the origin of the ductus arteriosus More common in males It is a feature of turner syndrome

Pathophysiology:

Arterial blood bypasses the obstruction reaching the lower part of the body through collaterals vessels. Left ventricle hypertrophies to overcome the obstruction heart failure. Systolic blood pressure in the upper part of the body is elevated. Neonates or infants with severe COA: CHF Asymptomatic or weakness or pain in legs after exercise.

Clinical features:

O/E:

The classical signs of COA is a disparity in pulsations & blood pressure of the arms and legs The peripheral pulses are weak in contrast to the bounding pulses of the arms There is radio-femoral delay, significant hypertension in the upper limbs. Short systolic murmur along the left sternal border at the 3rd and 4th intercostal space and on the back

Diagnosis:

CXR :
cardiac enlargement mainly left ventricle Rib notching due to enlarged intercostal arteries

ECG:
Left ventricular hypertrophy

Treatment:

surgery

Cyanotic CHD
Divided into two:

Cyanotic with decreased Pul blood flow:

Examples are : TOF, Pul atresia,Tricuspid atresia,Total anomalous PUL venous return with obstruction

Cyanotic with increased Pul blood flow:

Examples are : TGA, single ventricle ,truncus arteriosus ,Total anomalous Pul venous return without obstruction

Evaluation of the critically ill neonate with cyanosis & respiratory distress : / :

Cardiac disease CNS disease like intracranial hemorrhage Pulmonary disease like RDS

Hyperoxia test:

Administration of 100% oxygen will usually not raise the arterial PaO2 in CHD

Tetralogy of Fallot (TOF)

Consists of the combination of :

Obstruction of the Rt ventricular outflow Pul stenosis. VSD Dextroposition of the aorta with septal overriding Rt ventricular hypertrophy.

Pathophysiology:

Systemic venous return to the Rt atrium & Rt ventricle is normal When the Rt ventricle contracts in the presence of marked Pul stenosis , the blood is shunted across the VSD into the aorta Persistent arterial desaturation & cyanosis result The degree of Rt ventricular outflow obstruction determines the timing of onset of symptoms ,the severity of cyanosis and the degree of Rt ventricular hypertrophy.

Clinical manifestations:

Cyanosis is not often present at birth Dyspnoea on exertion ,characteristically they assume a squatting position for the relief of dyspnoea. Paroxysmal hyercyanotic attacks or blue spells:
Occurs more frequently in the morning or following episodes of vigorous crying The child become hyperpneic & restless ,cyanosis increased Syncope may follow It may last from minutes to few hours They are rarely fatal but can be followed by convulsions or hemi paresis The spells are associated with reduction of already compromised Pul blood flow---hypoxia & metabolic acidosis

Poor growth & development

O/E:

Systolic murmur along left sternal border due to turberalence flow across the Rt ventricular outflow tract accompanied by thrill.

Diagnosis:
CXR: narrow base ,rounded apical shadow situated higher above the diaphragm , produced by hypertrophied Rt ventricle" boot shape

ECG: Rt axis deviation ,Rt vent hypertrophy Echo. Catheterization

Complications:
Cerebral thrombosis due to polycythemia, brain abscess, bacterial endocarditis, CHF is not a feature of TOF

Management
Cyanotic spells

Placement of the child on the abdomen in the chest knee position Oxygen Morphia 0.1mg/kg/SC Beta blocker 0.2mg/kg.
Blalock Taussig shunt : anastomosis of a subclavian artery to the homolateral branch of the Pul artery Total correction : relieve of the obstruction to the Rt ventricle + closure of the VSD.

Surgical correction of TOF:

Transposition of the great arteries (TGA)

The aorta arise from the Rt Vent & the Pul artery from the Lft Vent The systemic & Pul circulation consist of two parallel circuits The only mean of survival is provided by the foramen ovale ,ductus arteriosus or VSD

Clinical presentation:

According to the anomaly found Progressive cyanosis & heart failure may follow

Investigation:

CXR : heart looks like an egg on side Catheterization

Treatment :

A communication between systemic & Pul circulation is urgently needed Arterial switch procedure should be carried out in the first 2 weeks of life.