16.2.0 Introduction
These can be divided into two main groups: congenital heart disease (existing before
or at birth); and those disorders that are acquired after birth. Congenital heart disease
occurs in approximately 8 children in every 1000 live births. There is a wide spectrum
of severity, but 2-3 of these children will be symptomatic in the first year of life.
16.2.1 Congenital heart defects
The cause is rarely known in individual cases but multifactorial inheritance patterns
are mainly responsible. Several chromosomal abnormalities, such as Down syndrome,
are associated with severe congenital heart disease but these represent fewer than 5%
of the total. The main types of congenital conditions are shown in 1079HTable 16.1. In most
instances there is a combination of genetic and environmental influences, including
infections, during the second month of pregnancy.
Many defects are slight and cause little disability, but a child with more severe defects
may present with breathlessness on exertion, tiring easily, and suffer from recurrent
respiratory infections. Those children with severe defects such as tetralogy of Fallot
and valvular defects, including pulmonary atresia and tricuspid atresia, will have
cyanosis, finger-clubbing, and may have delayed growth and development (1080HFigs. 16.1,
1081H16.2, and 1082H16.3). Characteristically, these children will assume a squatting position to
relieve their dyspnoea (breathlessness) on exertion.
Heart murmurs
The incidence of congenital heart disease is falling, affecting 7-8 infants per 1000.
Many parents will report that their child either has, or had, a 'heart murmur'. These
may only be discovered at a routine examination, although they occur in over 30% of
all children. Most of these murmurs are functional or innocent and not associated with
significant abnormalities, but are the result of normal blood turbulence within the
heart. Innocent murmurs are heard most frequently from 3-7 years of age. In a small
minority of cases a heart murmur indicates the presence of a cardiac abnormality
causing the turbulence. If the dentist is in any doubt about the significance of a
murmur, then a cardiological opinion should be sought. Normally contact with the
child's medical practitioner will clarify the situation. Innocent murmurs do not require
any special precautions or treatment.
Ventricular septal defects (VSD)
These are the most common of the cardiac malformations. Small defects are
asymptomatic and may be found during a routine physical examination. Large defects
with excessive pulmonary blood flow are responsible for symptoms of breathlessness,
feeding difficulties, and poor growth. Between 30% and 50% of the small defects
close spontaneously, usually within the first year of life. Larger defects are usually
closed surgically in the second year of life, but defects involving other cardiac
structures may require complex surgery or even transplantation.
Atrial septal defects (ASD)