Congenital Heart Disease

Congenital heart disease is defined as a gross structural abnormality of the heart or intrathoracic great vessels that is actually or potentially of functional significance.

• Etiology largely unknown
• Multifactorial in most cases
• Solely of genetic origin in 5%
• Purely environmental factors in 2%
• Sex predilection of some defects
• Males: AS, CoA, TGA, TOF
• Females: ASD, VSD, PS, PDA

Introduction

• Most common congenital heart disease
• May occur singly or in combination with other defects
• Any portion of the interventricular septum may be involved
• Severity ranges from mild to severe

Epidemiology

• Responsible for between 20-45% of congenital heart disease as a solitary lesion
• Incidence at birth: 5-50 per thousand births
• Slightly commoner in females than males (54% vs 46%)

Etiology

• Unknown in majority of cases
• Usually multifactorial
• Associated with several chromosomal disorders
• Trisomy 21
• Trisomy 18
• Trisomy 11
• Holt-Oram syndrome
• DiGeorge syndrome
• Turner syndrome
• Recurrence risk:
• Paternal VSDs - 2%.
• Maternal VSDs - 6% to 10%

Classification of VSDs

• Inlet (5-8%)
• Trabecular (5-20%)
• Outlet (5-7%)
• Perimembraneous

Pathophysiology

Natural History

• The natural course of a VSD depends to a large degree on the size of the defect
• 30–50% of small defects close spontaneously
• Small muscular VSDs are more likely to close (up to 80%) than membranous VSDs are (up to 35%)
• Most defects that will close do so in the first 4 years.
• VSDs with septal aneurysm tissue limiting the magnitude of the shunt may close

Clinical Presentation

― Small defect:

• Murmur may be heard at 1-6 weeks
• Usually healthy
• Normal feeding, growth and development
• Risk of infective endocarditis
• Precordial activity is normal
• Systolic thrill is prominent
• Grade IV-VI holosystolic murmur heard maximally at the LLSE
• Murmur may radiate to the pulmonary area or sternum
• May have wide splitting of the second heart sound

― Moderate and large defects

• Symptoms develop as early as 2 weeks but may be delayed till about 6 weeks
• Initial symptoms consist of
• Tachypnea with increased respiratory effort
• Excessive sweating
• Fatigue when feeding: usually begins during the first month and increases in severity as pulmonary vascular resistance decreases.
• Symptoms often preceded by a respiratory tract infection
• Poor weight gain
• Precordial activity is increased
• Left chest bulge may develop at 4-6 months
• Thrill is present
• Grade III-VI holosystolic murmur is heard loudest at the LLSE
• Third heart sound is usually present
• Pulmonary component of S2 is usually loud

Diagnosis

Chest Xray

Electrocardiogram

• Sinus tachycardia
• Left atrial enlargement
• Left ventricular hypertrophy
• Right ventricular hypertrophy with Eisenmerger physiology

Echocardiography

[video]

MRI

Treatment

Depends on the size

• Small defects
• Reassure parents
• Surgical closure not indicated
• May require infective endocarditis prophylaxis
• Monitor for closure
• Large defects
• Medical management

Aim: Control heart failure symptoms and maintenance of normal growth

• Diuretics
• Angiotensin converting enzyme inhibitors
• Digoxin
• VSD closure
• Surgical
• Catheter occlusion techniques

Indications for surgical closure

• Patients at any age with large defects in whom clinical symptoms and failure to thrive cannot be controlled medically
• Infants between 6 and 12 mo of age with large defects associated with pulmonary hypertension, even if the symptoms are controlled by medication;
• Patients older than 24 mo with a Qp : Qs ratio greater than 2 : 1.
• Patients with supracristal VSD of any size

Introduction

• Any opening in the atrial septum, other than a competent foramen ovale, is an atrial septal defect
• Can occur in any portion of the atrial septum
• Ostium secundum defects: 5% to 10% of all congenital heart defects
• Ostium primum defects: 1-2% of all CHD
• Sinus venosus defects: <1% of CHD
• Female: Male 2:1

Classification

• Ostium primum
• Ostium secundum
• Sinus venosus
• Single atrium

Etiology

• Most cases are sporadic
• Holt-Oram
• Missense mutation on chromosome 14q12
• Down syndrome
• Ellis Van Creveld syndrome

Pathophysiology

• Atrial level left to right shunting leads to right atrial enlargement and RVH
• With large defects, Qp : Qs is usually between 2 : 1 and 4 : 1.
• The paucity of symptoms in infants with ASDs is related to the muscular and less compliant structure of the right ventricle in early life

Clinical manifestations

• Often asymptomatic in childhood
• Usually detected incidentally
• Ostium primum defects may present earlier
• With large ASDs, there may be:
• Failure to thrive
• Exercise intolerance
• Congestive cardiac failure
• Examination of the chest may reveal a mild left precordial bulge.
• Parasternal heave is present
• A loud 1st heart sound and sometimes a pulmonic ejection click can be heard.
• In most patients, the 2nd heart sound is characteristically widely split and fixed in its splitting in all phases of respiration
• Ejection systolic murmur is usually present
• A short diastolic murmur at the LLSE may be heard
• Patients with moderate ostium primum shunts and mild mitral insufficiency present like ostium secundum ASD but with an additional apical murmur caused by mitral insufficiency.

Investigations

• Varying degrees of enlargement of the right ventricle and atrium, depending on the size of the shunt.
• The pulmonary artery is large, and pulmonary vascularity is increased

Chest Xray

Electrocardiogram

• Right atrial enlargement
• Right axis deviation
• Features of RVH
• rsR pattern in the right precordial leads

Echocardiogram

[video: ostium primum]

MRI

Treatment

• In infants with CHF, medical management (with a diuretic) is recommended
• Surgical or transcatheter device closure is advised for all symptomatic patients and also for asymptomatic patients with a Qp : Qs ratio of at least 2 : 1.

• Failure of closure of the ductus arteriosus after birth
• Common condition among preterms
• May occur singly or in association with other congenital heart disease

Epidemiology

• Commonest congenital heart disease among preterms
• Responsible for between 5-10% of all CHD globally (as high as 18% in Nigeria)
• Equal sex distribution

Pathophysiology

Clinical Features

• Often presents in the first 4-6 weeks of life
• May present earlier, especially in preterms
• Asymptomatic if small

Larger PDAs present with:

• Difficulty in breathing
• Failure to thrive
• Respiratory tract infections
• Features of heart failure
• Wide pulse pressure with bounding pulses
• Loud pansystolic murmur lateral to pulmonary area in younger infants.
• Classical continuous murmur seen in the older child

Diagnosis

Chest radiograph

ECG

• Left axis deviation
• LAE, LVH

Echocardiogram

• Ductus visualized
• Continuous flow
• Dilated LA, LV
• Dilated proximal aorta

Angiography

[video]

Treatment

• Medical management of heart failure
• Small frequent feeds
• Oxygen, when necessary
• Indications for closure
• All symptomatic PDAs
• Asymptomatic PDA with LA/LV volume overload
• Types of closure
• Medical
• Oral indomethacin
• Oral ibuprofen
• Oral paracetamol
• Surgical
• Ligation
• Ligation and division
• Transcatheter
• Amplatzer devices
• Coils

Prognosis

• Generally good
• Methods of closure are all associated with minimal morbidity or mortality

• Commonest cyanotic congenital heart disease beyond the neonatal period
• Anterior and cephalad deviation of the conal septum result in the disease complex of :
1. RVOT obstruction
2. Large outlet VSD
3. Aorta overriding the septal defect
4. Right ventricular hypertrophy
• Associations include right sided aortic arch, ASD, mitral regurgitation, coronary anomalies

Pathophysiology

• Pathophysiologic abnormalities result from:
• Reduced pulmonary blood flow and Rt  Lt shunt lead to persistent cyanosis and hypoxaemia
• Infundibular spasm and/or imbalance in systemic to pulmonary resistance/ flow  Episodic increase in hypoxaemia, cyanosis, acidosis and accompanying clinical features (hypercyanotic or tet spell)
• Long standing hypoxaemia  Increased RBC production (polycythaemia) with or without accompanying iron deficiency

Clinical features

• Typically present in mid infancy
• May present at birth when pulmonary stenosis is very severe or in pulmonary atresia
• Major manifestation is increasing cyanosis with fast breathing, poor weight gain.
• Dyspnoea on exertion as child grows older
• Squatting
• Tet spells: Most frequently seen in first two years of life
• Cyanosed, plethoric
• May have digital clubbing
• Parasternal heave
• Loud ejection systolic murmur at pulmonary area with single second heart sound
• Murmur intensity diminishes during tet spells
• Tachypnea

Diagnosis

Chest radiograph

Echocardiography

Treatment

Hypercyanotic spell

• Place in knee chest position
• Calm the child
• Oxygen
• Subcutaneous morphine 0.2mg/kg
• Intravenous bicarbonate
• Drugs that increase systemic vascular resistance
• Phenylephrine
• Ketamine
• IV propranolol

Medical Management

• Oral propranolol 0.5 – 1mg/kg per dose every 6-8 hours
• Monitor growth and development
• Monitor packed cell volume, iron status
• Partial exchange transfusion and replacement with saline
• Infective endocarditis prophylaxis

Surgical Management

• Palliative
• Blalock-Taussig shunt
• Pott shunt
• Waterston shunt
• RVOT stenting
• Definitive
• Intracardiac repair: Relief of RVOT obstruction and patch closure of VSD ± transannular patch

Complications of TOF

• Cerebral abscess
• Polycythaemia
• Iron deficiency
• Renal failure
• Cerebrovascular accident
• Infective endocarditis
• Bleeding

• Commonest cyanotic congenital heart disease presenting in newborn period
• Ductal dependent lesion in its most common form
• Common associations are VSD (30-40%), ASD, PDA, LVOT obstruction (5%), Ventricular inversion
• Aorta arises partly or completely from the RV
• Pulmonary artery arises from the LV
• The result of D-TGA is complete separation of the pulmonary and systemic circulations.
• This results in hypoxemic blood circulating throughout the body and hyperoxemic blood circulating in the pulmonary circuit, which is not compatible with survival

Clinical presentation

• Present acutely ill looking in the first few days of life with deep cyanosis, and in heart failure (related to closure of the DA)
• The S2 is single and loud.
• No heart murmur is heard in infants with an intact ventricular septum.
• An early or holosystolic murmur of VSD may be audible in less cyanotic infants with associated VSD. A soft midsystolic murmur of pulmonary stenosis (PS or LVOT obstruction) may be audible.
• If CHF supervenes, hepatomegaly and dyspnea develop

Diagnosis

Chest radiograph

Treatment

• Measures to keep ductus arteriosus open
• Intravenous prostaglandin E1 0.01-0.2µg/kg/min
• Monitoring closely arterial blood gases
• Measures to ensure mixing
• Atrial septostomy
• Surgical repair
• Palliative
• Arterial switch
• Atrial switch
• Others

Clinical presentation

• Cyanosis may be seen immediately after birth.
• Signs of CHF develop within several days to weeks after birth.
• History of dyspnea with feeding, failure to thrive, and frequent respiratory infections is usually present in infants.
• The peripheral pulses are bounding, with a wide pulse pressure. The precordium is hyperactive and the apical impulse is displaced laterally.
• A systolic click is frequently audible at the apex and upper left sternal border. The S2 is single.
• A harsh (grade 2 to 4/6), regurgitant systolic murmur, which suggests VSD, is usually audible along the left sternal border.

Types

• Supracardiac
• Cardiac
• Infracardiac
• Mixed

Clinical presentaion

• Cyanosis
• Cardiac failure
• Failure to thrive
• Hyperactive RV impulse
• Widely split S2
• Grade 2-3ESM at Pulm area