ultrasound diagnosis of fatal anomalies

TETRALOGY OF FALLOT
Extrasystoles (Supraventricular)
Definition: This is defined as heart beats occurring
additionally to the sinus rhythm. The most
frequent cause of extrasystoles is premature
contractions of the atrium, which appear more
than 8 ms prior to the expected atrial contractions.
The stimulation arises mostly from an ectopic
focus within the atrium and not from the
sinoatrial node.
Procedure after birth: If the arrhythmia is present
until just before birth, then 24-h monitoring
of the heart frequency of the newborn is recommended.
ECG is useful.
Prognosis: Spontaneous remission in the late
stages of pregnancy or just after birth is the usual
course.
Incidence: Seen often in the early stage of the
third trimester.
Clinical history/genetics: Caffeine intake by the
mother has been described as a possible cause.
Certain drugs may also be responsible (fenoterol
and some vasoactive substances such as those in
nasal sprays).
Associated malformations: Structural cardiac
anomalies; 1% of cases may be complicated by
development of supraventricular tachycardia.
Ultrasound findings: The arrhythmic contractions
are first diagnosed in B-mode. They can be
differentiated further using M-mode.
Clinical management: Further sonographic
screening, including fetal echocardiography, to
exclude cardiac anomaly. Weekly control of the
heart frequency is necessary for early detection
and treatment of supraventricular tachycardia,
before the development of cardiac failure with
fetal hydrops. Abstinence from caffeine is advised
and β-mimetics should be avoided.
Tetralogy of Fallot
Definition: A combined cardiac malformation
consisting of four anomalies: VSD, pulmonary
stenosis, hypertrophy of the right heart (postnatal)and
overriding of the aorta (over VSD).
Incidence: One in 2000 births, 6–10% of all congenital
heart malformations.
Clinical history/genetics: Mostly a sporadic,
multifactorial inheritance. Recurrence rate of
2.5% with one affected sibling and of 8% when
two siblings are affected; in case of an affected
References
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9.
mother the probability of recurrence is 2.5 %,
and with an affected father it is 1.5%. Autosomaldominant
inheritance has also been reported in
rare cases.
Teratogens: High doses of Vitamin A, thalidomide,
trimethadione, sexual steroids and alcohol.
Associated malformations: Extracardiac malformations
are seen in a total of 16%.
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