Quiz 2 Review

UT 609B - OB 2

4 chamber (4CH) view

• Most important view (many anomalies seen in this view)

• Chambers:

  • RT atrium (RA)

  • LT atrium (LA)

  • RT ventricle (RV)

  • LT ventricle (LV)

• Valves:

  • Tricuspid valve (TV)

  • Mitral valve (MV)

Tricuspid valve (TV)

Valve between RA and RV

Mitral valve (MV)

Valve between LA and LV

Normal US findings of 4CH view

• Heart is in LT chest and fills ~⅓ of chest cavity

• Apex points ~45° to LT anterior chest wall

• Ventricles are the same size

• FO flap opens into LA

• Moderator band seen in apex of RV

• Valves separating atria and ventricles

• Blood in LV extends fully to apex

Which heart chamber is always in front of the aorta?

LA

Anomalies seen in 4CH view

• Single ventricle 

• Hypertrophy, hypoplasia, atresia of chambers 

• Tricuspid or mitral valve atresia 

• Atrial/ventricular septal defects 

• Cardiomyopathy 

• Endocardial cushion defects

• Aortic/pulmonary stenosis - seen better in outflow tract views

• Ebstein’s anomaly

Aortic valve (AV)

Separates LV and aorta

LT ventricular outflow tract (LVOT)

• Aortic and LV connection

• LA

• Aortic root

• Aortic valve (AV)

• Ventricular septum

RT ventricular outflow tract (RVOT)

• Pulmonary artery (PA)

• Pulmonic valve (PV)

• RV

Pulmonic valve (PV)

Separates RV and PA

Anomalies seen on outflow tract views

• Transposition of the great vessels

• Tetralogy of Fallot

• Double-outlet RV

• Pulmonary stenosis

3 vessel heart view (3VV)

• Useful for assessing the great vessels 

• In a straight line from LT ant to RT post, size decreases from LT-RT

• Structures

  • Pulmonary artery (PA)

  • Aorta (AO)

  • Superior vena cava (SVC)

3 vessel trachea view (3VTV)

• PA

• AO

• SVC

• Trachea

Aortic arch

• Turn 90 degrees from 3VV

• Vessels coming off to feed the neck/brain

• From the center of the heart

• Candy cane appearance

Ductal arch

• From the ant chest wall

• No vessels coming off to feed the neck/brain

• Hockey stick appearance

Cardio system cells (heart, vessels, blood) come from …

Mesodermal layer

Embryology

• Cardio system is one of the first systems to appear and function

  • Blood circulates in embryo by 3rd conceptual/5th menstrual week

• Heart begins as cardiogenic cords (paired tubular structures) that fuse on day 22

• Embryonic heart forms by beginning of 6th menstrual week → placenta circulation begins

• Best time to evaluate heart is at 18-22 weeks 

Heart starts beating on day ___

22

Primitive heart changes to 4CH by ___ menstrual weeks

11

Features of fetal circulation

• Non-functioning lungs

• Blood flows from placenta to heart

  • Fetal cardio circulation begins at the placenta

• Shunts that bypass the liver and lungs

Shunts that bypass the liver and lungs

• Placenta

• Ductus venosus

• Foramen ovale

• Ductus arteriosus

Ductus venosus

Venous connection from the umbilical vein to IVC

Ductus arteriosus

• From pulmonary artery into descending aorta

• Seals within 24 hrs after birth

Normal fetal HR

100-180 bpm

Transient bradycardia normal in trimester ___ only

2

Tachycardia

Abnormally fast heart rate (180-300 bpm)

Bradycardia

Abnormally slow heart rate (< 100 bpm)

Foramen ovale (FO)

• Normal atrial septum opening allowing blood to flow from RA to LA in utero

  • Septum primum

  • Septum secundum

• ~40% of fetal blood flows through FO 

• Seals within 24 hours after birth

  • Closes due to 

    • Decreased RT heart pressure and PVR (pulmonary vascular resistance)

    • Increased LA pressure

Patent foramen ovale (PFO)

• Not a true ASD (no septal tissue is missing)

• 70-75% of PFO close by 2 years old

T/F: Heart abnormalities are some of the most common congenital defects

True

T/F: Ao → LV

True

T/F: PA → RV

True

Hypoplastic LT heart

• Most severe form of CHDs

  • Most common cause of death from CHD in early neonatal period

• Underdevelopment of LV, MV, Ao, and AV

• 13% of all CHDs

• More common in males

• Always lethal

• US findings:

  • Small Ao

  • Small or absent LV

Cardiomyopathy (CMP)

Abnormally large heart (takes up more than ⅓ of fetal chest)

Ventricular septal defect (VSD)

• Most common congenital heart defect (1/400 cases)

• Abnormal connection between RV and LV

• US findings:

  • Defect in the interventricular septum (IVS)

  • Blood shunts between ventricles w/ color Doppler

Atrial septal defect (ASD)

• Abnormal connection between RA and LA

• US findings:

  • Defect between atriums

  • Missing septum secundum, septum primum, or both

Atrioventricular septal defect (AVSD)

• AKA endocardial cushion defect

• Fetus has both ASD and VSD

• US findings: large defect along cardiac midline

Transposition of the great vessels

• PA and Ao are swapped

  • PA exits from left ventricle 

  • Ao exist from right ventricle

• Associations: VSD, patent ductus arteriosus and foramen ovale, and atrial septum defects

Ectopic cordis

• Herniation of heart into amniotic cavity through defect

• US findings: heart seen outside of thoracic cavity

Echogenic intracardiac focus (EIF)

• Microcalcification in papillary muscle

• Can be in LV or RV

  • EIF seen in RV is more often associated w/ aneuploidy

• Normal variant if seen on its own

  • If seen w/ other anomalies → increased risk of aneuploidy

Double outlet RV

• Ao and PA arise from the RV

• US findings:

  • VSD almost always present

  • Linear alignment of Ao and PA

  • Shared origin of Ao root and PA

  • Ao is more anterior than PA on 3VV

Tetralogy of Fallot

• Y-shaped overriding aorta with outflow from both ventricles

  • PA stenosis

• VSD

• RV outflow anomalies

• RV hypertrophy

  • Muscle has to work harder to pump blood through PV

Tricuspid atresia

• Failure of the TV and RV to form properly

• US findings:

  • Absent TV, hypoplastic RV and PA, enlarged RA and LV

  • ASD or VSD

  • 3VV shows small PA

Double inlet LV

• LA and RA feed into LV

• US findings: single ventricle + 2 atria w/ valves on 4CH

Ebstein’s anomaly

• TV displaced inferiorly in RV 

• US findings: 

  • Enlarged RA (due to displacement), small RV

  • Inferior displacement of TV

  • Pericardial effusion

Coarctation of the aorta

• Narrowing of aortic lumen

• US findings: 

  • Narrowed aortic arc

  • Disproportionate ventricle sizes

Rhabdomyoma

• Most common benign cardiac tumor (prenatally diagnosed)

• Associations:

  • Tuberous sclerosis (60-80%)

  • Arrhythmias

  • Valve obstruction

• US findings:

  • Echogenic mass within RV or LV

Fetal pericardial effusion

• Accumulation of fluid in the pericardial sac

  • Normal amount of fluid < 2 mm

Hydrops fetalis

• Abnormal amount of fluid build up in 2+ areas of the body

  • Pericardial effusion

  • Pleural effusion

  • Ascites

  • Cystic hygroma

  • Skin edema 

• Two types: immune and nonimmune

Immune hydrops fetalis

• Complication of severe form of Rh incompatibility

  • Mother has Rh negative, fetus has Rh positive 

• Medication: RhoGAM - prevents mother from making antibodies against baby

Nonimmune hydrops fetalis

• Disease or medical condition affects body’s ability to manage fluid 

  • 3 main causes: lung/heart problem, severe anemia, genetic/developmental problems

• 90% of cases

	Notes	AFI	MVP
Normal	If abdomen wall hits uterine wall on 2 sides, still normal	?	?

• AFI: 5-24 cm

• MVP: 2-8 cm

	Notes	AFI	MVP
Polyhydramnios	Abnormally increased amount of amniotic fluid Primary sign of underlying fetal disorder	?	?

• AFI > 24 cm

• MVP > 8 cm

	Notes	AFI	MVP
Oligohydramnios	Abnormally decreased amount of amniotic fluid Conditions that allow a DRIPP of fluid D - demise  R - renal abnormalities  I - IUGR P - PROM P - post dates	?	?

• AFI < 5 cm

• MVP < 2 cm

What does D stand for in DRIPP?

Demise

What does R stand for in DRIPP?

Renal abnormalities

What does I stand for in DRIPP?

IUGR

What do the Ps stand for in DRIPP?

PROM and post dates

Congenital diaphragmatic hernia (CDH)

• Herniation of stomach/bowel/spleen into thoracic cavity through diaphragmatic defect

• Result of incomplete fusion of diaphragmatic structure at 6-10 menstrual weeks

• Most common: LT-sided herniation (95%)

Pulmonary sequestration

• Accessory fragment of lung with its own separate arterial circulation 

• Two types: intralobar and extralobar

Intralobar pulmonary sequestration

• Most common, 85% of cases

• Closely connected to adjacent normal lung and no separate pleural space 

• US findings: 

  • Well-defined echogenic mass adjacent to normal lung 

  • Feeder vessel originating from aorta seen w/ color

Extralobar pulmonary sequestration

Congenital cystic adenomatoid malformation (CCAM)

• Abnormality of lung development where normal lung is replaced by nonfunctioning cystic tissue 

• Most often unilateral and affects entire lung lobe 

• Mediastinal shift → increased likelihood of fetal demise

• Three forms

Type I CCAM

• Most common, 70% of cases

• Macrocystic, nonvascular cystic mass in fetal lung

Type II CCAM

• Multiple small cysts 

• Homogeneously echogenic lobes

Type III CCAM

• Microcysts or noncystic lesions w/ mediastinal shift 

• Mediastinal shift + lateral displacement of heart

Tracheal atresia

• Lethal condition where trachea fails to form or is obliterated by external compression

  • Obstruction typically at level of larynx 

• US findings: 

  • Bilateral enlarged echogenic lungs, fluid-filled trachea, reduced cardiothoracic circumference ratio, polyhydramnios

Achondrogenesis

• Rare and lethal group of genetic disorders that impair cartilage and bone development

• Associated w/ IUGR, cleft soft palate, cystic hygroma, and hydrops fetalis

• US findings:

  • Hypomineralization (absent ossification of vertebral bodies) 

  • Narrow thorax

  • Bone fractures

  • Micromelia

  • Micrognathia

  • Large head w/ slightly decreased ossification of the cranium

Polydactyly

• Presence of extra digits on the fetal hands or feet

• One of the most common hand anomalies

• Can be an isolated finding or part of a syndrome

  • Short polydactyly syndrome, asphyxiating thoracic dysplasia, trisomy 13, trisomy 18, and trisomy 21

Rocker bottom foot

Associated with trisomy 13, trisomy 18, and spina bifida

Club foot (AKA talipes equinovarus)

• Most common skeletal anomaly seen in routine OB exams

• Caused by a shortened Achilles tendon → foot turns in and under

• Twice as common in males

• Can be an isolated finding or part of a syndrome

  • Meckel-Gruber, triploidy, Ehlers Danlos, Ellis Van Creveld, Noonan syndrome, trisomy 13, trisomy 18

• Treatment - casting and bracing

Syndactyly

Soft tissue or bony fusion of digits

Thanatophoric dysplasia

• Severe short-limb dwarfism syndrome that is usually lethal in perinatal period

• Most common form of lethal skeletal dysplasia due to breathing difficulties that lead to respiratory failure

  • Thanatophoric - Greek for “death bearing”

• Poor prognosis, still birth, or death after birth due to pulmonary hypoplasia

• More common in males

• Etiology - autosomal dominant inheritance of FGFR3 gene

• Two types

• Associated w/ macrocephaly, hydrocephalus, patent ductus arteriosus, ASD, horseshoe kidney, hydronephrosis, and imperforate anus

• US findings:

  • Frontal bossing (clover-leaf skull)

  • Hypoplastic thorax (small thorax w/ normal trunk)

    • Bell-shaped chest

  • Curved long bones

  • Hypomineralization

  • Macrocephaly

  • Fetal bones are normal

Rhizomelia

Proximal segment of a limb is shortened (humerus or femur)

Micromelia

Proximal and distal segments of all limbs are shortened

Mesomelia

Distal segment of a limb is shortened (radius/ulna or tib/fib)

Amelia

Absence of an extremity