cardiac

Congenital Heart Disease

Classification:
Acyanotic congenital heart diseases:forming 2/3 of all.
usually less complex. Such defects cause an increase in the work imposed on the heart because of either:
Left-Right shunt with increase pulmonary blood flow leading to increase in volume work of the heart. E.g.; patent ductus arteriosus (PDA), atrial septal defect (ASD) and ventricular septal defect (VSD).
Obstruction of the blood flow across a heart valve on the left side of the heart, such as aortic stenosis, or in the aorta itself, as coarctation of the aorta.
Typically, acyanotic congenital heart disease presents as heart failure in infancy with repeated chest infections because of pulmonary congestion caused by increased pulmonary blood flow or resulting from an obstructive lesion.

Cyanotic congenital cardiac lesions:forming 1/3 of all congenital heart disease

Right-Left shunt causing decreased pulmonary blood flow. Many of these lesions consist of a septal defect with a Right Sided obstructive lesion causing an obligatory Right-Left shunt. E.g.; TOF, Tricuspid Atresia, …etc.
Parallel systemic and pulmonary blood flow rather than in series. If no mixing occur the condition will be incompatible with life. Mixing occurs through a patent foramen ovale, an ASD, a VSD or less commonly a PDA. The most common example of this is (TGA).
Defects in the connections of the heart in which there is mixing of the systemic and pulmonary flows. An example of such a complex lesion is total anomalous pulmonary venous drainage (TAPVD), Truncus Arteriosus, and others

Cyanotic heart disease

Acyanotic heart disease
TOF Tetralogy of Fallot
PDA Patent Ductus Arteriosus
TGA Transposition of great arteries.
ASD Atrial Septal defect
TAPVD Total anomalous of pul v. drainage
VSD Ventricular Septal defect
TA Tricuspid Atresia
COA Coarctation of Aorta
IAA Interruption of Aortic Arch
DORV Double Outlet Rt Ventricle
AP window Aorto-pulmonary window
Ebstein`s anomaly.
PAVCD Partial Atrio-Vent. Canal Defect
CAVCD Complete Atrio-Vent. Canal Defect
HLHS Hypoplastic left heart syndrome
Truncus Arteriosus


Acyanotic Congenital Heart Disease

Patent ductus Arteriosus (PDA)

Normally, functional closure of the ductus occurs within a few hours of birth & is abnormal if persists beyond neonatal period. closure occurs in response to an increase in peripheral oxygen saturation & a drop in the pulmonary vascular resistance as the lungs expand.
PGs inhibitors , such as indomethacin, may be used therapeutically to close the ductus in the first few weeks of life.
Clinical presentation :-
In isolated PDA, there is a Left-Right shunt of blood, resulting in a high pulmonary blood flow.
Small shunts usually cause few symptoms and signs apart from the continuous machinery murmur.
Larger ducts cause heart failure and failure to thrive & can eventually lead to shunt reversal with cyanosis and clubbing.
Diagnosis :-
Echocardiography with color flow Doppler imaging.
Cardiac catheterizationis performed only if additional lesions are suspected or for duct closure
Management :-
After 6 months of age, spontaneous closure of a PDA is rare. Most should be closed by preschool age, regardless of the presence or absence of symptoms. Methods of PDA closure:
Prostaglandins, such as indomethacin, may be used therapeutically to close the ductus in the first few weeks of life. (especially in premature babies)
Interventional cardiology with an umbrella or coil duct occlusion device inserted percutaneously (in cardiac catheterization lab).
If large surgical closure through a left thoracotomy is preferred.

Coarctation of the aorta

Haemodynamically significant narrowing of the aorta, usually in the descending aorta just distal to the left subclavian artery (called juxta-ductal or post-ductal), typically puts a pressure load on the left ventricle, which can ultimately fail.
The upper body is well perfused but the lower body, including the kidneys, is poorly perfused, leading to fluid overload, excess renin secretion and acidosis.
Clinically :-
In the neonatal period:- 'infantile' or pre-ductal Coarctation where blood flow to the lower body occurs through the PDA and as the PDA closes, perfusion to kidneys and lower body decreases significantly.
Symptoms of heart failure,child may appear well in first few days of life & as the ductus closes, the child-becomes progressively more unwell, acidotic, anuric, with lower body cyanosis despite normal pinkish upper body.
In adult-type Coarctation:- Juxtaductal or post-ductal
Obstruction is gradual with complications developing in adolescence or early adulthood. Hypertension is a common presenting problem, often upper body hypertension only. flow murmurs over the scapula Due to development of collateral vessels that may even cause rib-notching.


On examination:
Prominent pulsation in the neck, tired thin legs or evenintermittent claudication on exercise.
Radiofemoralpulse delay.
Murmur that is continuous and heard best over the thoracic spine or below the left clavicle.
Investigations :-
CXR:
Rib-notching because of dilated posterior intercostal vessels (collateral vessels)
The heart is usually of normal size in the older child and shows a classical 'three sign'
Echocardiography & cardiac catheterisation
Managements :-
Medical treatment:- control heart failure&hypertension.
In infants with ductal dependent blood flow; PG infusion to re-open the ductus and general resuscitation, before corrective surgery.
Surgical repairis the definitive treatment via a left thoracotomy.
Percutaneous balloon dilatation:- Alternative procedure in older children and adults and, in particular, after re-coarctationpost surgery.

Atrial Septal Defects (ASD):

Defect in the septum between the left and right atria leading to a Left-Right shunt, the significance determined by the size of the defect and the relative compliance of the ventricles (ability to distend).
Types of ASD:
Ostium secondum ASD: most common type, usually occurring in the area of the fossa ovalis. ASD secondum is usually asymptomatic in childhood with symptoms developing gradually at middle age as congestive heart failure with pulmonary hypertension or arrhythmias.
Ostium primum ASD: or called partial atrio-ventricular canal defect (PAVCD) or endocardial cushion defect. The ASD here is found near to the atrio-ventricular valves, usually associated with abnormalities in the mitral valve leading to mitral regurgitation. Presentation is usually earlier than those with secondum defects with dyspnea, recurrent chest infection, and congestive heart failure.
Sinus venosus ASD: rare defects usually highly located in the atrial septum near the junction of the SVC, usually associated with anomalous drainage of the right upper pulmonary vein to the SVC or right atrium.
Management :-
Closure is performed during the first decade of life, even in the absence of symptoms usually at preschool age.
ASD secondum may be occluded percutaneously through interventional cardiology.
ASD primum and sinus venosus as well as large ASD secondum need open surgical repair usually by a synthetic patch.
Primum ASD defects may require additional mitral valve repair.


Ventricular septal defects / VSD
A VSD is a defect in the interventricular septum that allows a left-to-right shunting of blood.
VSDs account for 20–30% of congenital heart disease and affect approximately 2 in 1000 live births.
With time pulmonary hypertension develops and if no intervention occurs, reversal of flow across the defect and Eisenmenger’s syndrome.
VSDs May occur in isolation or as part of a more complex set of cardiac abnormalities (TOF, CAVCD).
Types of VSD:
Perimembranous VSD (70-80%)
Muscular VSD (10-20%) most expected to close spontaneously.
Inlet type or called atrioventricular VSD
Outlet type or called subarterial or juxta-arterial VSD
Clinical presentation:
VSDs cause volume overload on the right side and increased pulmonary flow leading to pulmonary edema, repeated chest infections with failure to thrive usually starting at 2nd month of life.
With the onset of pulmonary hypertension symptoms tend to improve on the account of elevated pulmonary vascular resistance and right ventricular or biventricular failure.
Small VSDs may cause no symptoms other than a pansystolic murmur on the left parasternal area.
Small VSDs tend to cause loud murmurs while a large VSD especially one with associated pulmonary hypertension may be faint or low pitched.
In the first 5 years 30-50% of VSDs close spontaneously
Investigations :-
Echocardiography confirms the diagnosis and can estimate the degree of shunting across the defect.
Cardiac catheterization can assess the degree of pulmonary hypertension, confirm size, number and location of VSD(s). It is only indicated when echo studies are not conclusive.
Management :-
Surgical closure is indicated :-
For large defects orlarge shunts i.e; left-to-right shunts of > 2:1.
When there are signs of pulmonary hypertension and increasing pulmonary vascular resistance.
Presence of complications of VSD. These include:-
(1) Aortic regurgitation. (2) subpulmonary stenosis. (3) infective endocarditis.


Eisenmenger's syndrome
It occurs following the reversal of a left-to-right shunt across a cardiac defect.
ASDs, VSDs, and PDAs cause left to right shunts leading to an increase in the right ventricular pressure and pulmonary blood flow, which lead to compensatory RVH and pulmonary hypertension. Pulmonary hypertension will damage the pulmonary vasculature and result in gradual elevation of the pulmonary vascular resistance. Pulmonary hypertension to start with will increase RV pressure and therefore decrease shunting across the defect but as the pulmonary hypertension rises to become equal or higher than the systemic pressure, reversal of shunt occurs so desaturated blood crosses to the left side of the heart and the patient becomes cyanotic.

Symptoms :-

Dyspnoea is the most common clinical features.
Fatigue. chest pain.
Exertional dyspnea.
Hemoptysis.
On examination :-

Cyanosis.

Clubbing
Left parasternal lift.

Complications:

Polycythemia
Paradoxical emboli
Bleeding disorders
SBE
Arrhythmias
Syncope & death


Closure of the shunt is contraindicated if pulmonary hypertension is irreversible because the right-to-left shunt now serves to decompress the pulmonary circulation.
Eisenmenger's syndrome is becoming less common as corrective surgery is undertaken increasingly early and fewer patients develop a fixed increase in their pulmonary vascular resistance.

Cyanotic Congenital Heart Disease

Tetralogy of Fallot ( TOF)
4-6% of all congenital heart diseases. The four intracardiac lesions originally described :-
VSD.
Overriding aorta.
Pulmonary stenosis (usually infundibular or subpulmonary PS)
Right ventricular hypertrophy.
Clinically:-
There may be no symptoms at birth.
As PS progresses, cyanosis typically develops within the first year of life.
Squatting is an adaptation by the child to hypoxic spells. This increases systemic vascular resistance and the venous return to the heart and consequently blood is diverted into the pulmonary circulation with increased oxygenation.
Lethargy and tiredness are also common.
Diagnosis:
Clinically: cyanosis, clubbing of fingers, ejection systolic murmur at pulmonary area (2nd intercostal space to the left of the sternum).
CXR 'boot-shaped' heart with poorly developed lung vasculature (oligemic lungs).
Echocardiography is diagnostic.
Management:-
Single stage complete repair; close of the VSD, correct the overriding and enlarge right ventricular outflow)
Staged repair following an initial palliative shunt (systemic-to-pulmonary artery shunt e.g.; BT shunt), which diverts systemic blood into the pulmonary circulation to improve oxygenation and decrease cyanosis.


Transposition of the great vessels / TGA
2nd most common cyanotic CHD & is most common cause of cyanosis in the newborn period.
TGA results from abnormal development , when the aorta arises from the RV & pulmonary artery from the LV. → pulmonary and systemic circulations to run in parallel rather than in series,
Clinically :
The most obvious presentation is severe central cyanosis occurring in the first 48 hours of life
It is incompatible with life unless mixing of the blood occur through associated shunts such as a patent foramen ovale or associated VSD. However, if there is a large ASD or VSD there may be minimal cyanosis initially.
Typically, prognosis is poor and, as pulmonary vascular resistance PVR declines in the neonatal period, high pulmonary flow develops, with cardiac enlargement and left ventricular failure.
Investigations :-
CXR:- Pulmonary plethora, Heart having an 'egg on its side' appearance (aorta in front of pulmonary artery).
Cardiac catheterization.
Echocardiography.
Management :-
Initial palliation :
Percutaneous (Rashkind) balloon atrial septostomy in neonates with small PFOs to increase mixing and improve survival.
intravenous prostaglandin (PG) can be givento keep the ductus open.
Definitive repair
Arterial switch procedure(ASO), mostly carried out as a two-stage procedure
Atrial switch procedure
The long-term results are impressive and it has replaced the atrial switch or baffle (Mustard or Senning) operations.