Fetopathology and developmental pathology of the embryo and fetus: Congenital heart defects

+ Introduction

+ Support

+ Atlas of fetal pathology

+ Congenital malformations of individual organ systems

Congenital heart defects

Marta Ježová

Introduction

Congenital heart defects are congenital anomalies of the heart and big vessels. Prevalence is 6 – 8 for 1000 live-born children, but total occurence is higher.

Nowadays, these defects are mostly seen by fetal pathologist who autoptically examines spontaneous and induced abortions. Many of the heart defects are recognised and exactly diagnosed by the ultrasound screening during the 2nd trimester and are the reason for pregnancy termination between 20th – and 24th week. Suspicion for a congenital malformation can be already get at the ultrasound examination at the turn of the 1st and 2nd trimester (11th – 13th week).

Classification

Most frequent congenital heart defects:

isolated ventricular septal defect
isolated atrial septal defect
aortic and pulmonary stenosis
coarctation of the aorta
transposition of the great vessels
patent ductus arteriosus

Critical heart defects:

life threatening early after birth
demand urgent surgery
these are:
- hypoplastic left heart
- pulmonary atresia
- transposition of the great vessels
- tight coarctation of the aorta
- interruption of the aortic arch

Etiology

Genetic: trisomy 21, 18, 13, Turner syndrome, Di George syndrome (microdeletion of the 22nd chromosome)
Enviromental: alcohol (fetal alcoholic syndrome), infection (German measles), mother's diseases (phenylketonuria at breaking the diet by the mother, poorly compensated diabetes mellitus).
In most cases the etiology isunknown, probably multifactorial.

Clinical signs

Cyanotic defects: cyanosis is caused by right-to-left shunt, e.g.transposition of the great vessels — deoxygenated blood flows into the aorta
Noncyanotic defects: left-to-right shunt leads to increased pulmonary blood flow and pulmonary hypertension envolves gradually, e.g. the large defect of the ventricular septum. Eisenmengers complex is a complex of clinical symptoms in congenital heart defects with significant pulmonary hypertension. In the defects with initial left-to-right shunting the direction of the shunt gets reversed to right-to-left and late cyanosis appears. The patients are week, dyspnoic, often present with syncopas or hemoptysis, ictus, sudden death. Eisenmenger syndrome is irreversible. The prevention is early surgical therapy of congential heart defects prior to the developement of pulmonary arterial hypertension.
Defects with obstruction: left heart or right heart insufficiency (left heart insufficiency in coarctation of the aorta)
Heart failure in infants manifests by tiring with feeding, excessive sweating on the head, tachypnea
Failure to thrive
Murmurs, precordial whirl
Arythmias, changes in ECG
Increased risk of infective endocarditis
Hydrops fetalis is not a constant feature of cardiovascular malformations. It is seen in some cases of hypoplastic left heart syndrome, AV septal defects, hypoplastic right heart, prenatal closure of foramen ovale, Ebstein malformation

The clasification of congenital heart defects is possible from several points of view (functional, anatomical...). Following classification respects especially the anatomy of the heart defects. The defects may be either isolated or complex.

Defects of heart septum

Anomalies of the great arteries

Malformations of the valves

Malformations of the aortic arch system

Malformations of the venous system

Anomalies of situs and heart position

Di George syndrome