Best imaged between 18-22 wks. Cannot adequately assess structures prior to 16wks
Obtain
       4 chamber view (pic) see Aorta, pulmonary veins draining into LA
       right ventricular outflow tract (RVOT) shows LV, PA, RV, pulmonary valve (pic)
       left ventricular outflow tract (LVOT) shows LV, Ao, aortic valve (pic)
       M-mode doppler (pic)

Normal Findings
       size is 1/3 of thorax, with 45 leftward axis, with concordance of stomach
       right and left ventricular walls are equal in thickness with same size ventricles and atria
       no defects in ventricular septum
       tricuspid valve is slightly closer to apex than mitral valve with leaflets of same thickness
       <2mm of pericardial fluid is normal
       foramen ovale flap opens on the left
       Ao and pulm artery should be same size, otherwise consider shunts

4 Chamber View Abnormality
       detects 65% of cardiac abnormalities
       disproportional heart to thorax consider cardiomegaly or skeletal dysplasias
       LV smaller than RV: hypoplastic left heart/arch, or Ao coarct
       RV smaller than LV, pulmonary/tricuspid atresia, Ao stenosis/insufficiency (large LV)
       tricuspid towards apex with large RA: Ebsteins
       echogenic focus in ventricular chamber is caused by papillary muscle mineralization or chromosome abnormalities
       echogenic mass within ventricle: rhabdomyoma associated with tuberous sclerosis
       heart wall thickened: cardiomyopathy or endocardial fibroelastosis

Great Vessel Outflow Tract Views
       detect 25% of heart anomalies
       PA smaller than Ao consider tetralogy of Fallot, or hypoplastic right heart
       Ao smaller than PA: coarctation of aorta or hypoplastic left heart
       abnormal position of great vessels: transposition
       single large great vessel: truncus arteriosus and tetralogy of Fallot

Cardiac Arrhythmias
       use Mmode to assess both atria and ventricular motion simultaneously
       most common fetal arrhythmia is PVC's shown by early beat then compensatory pause and are usually innocent. Induced by smoking, caffeine, or alcohol. Tx with digoxin
       tachycardia >180bpm
       bradycardia <100bpm. transient bradycardia is common due to vasovagal response sometimes due to transducer pressure which returns to normal in 30sec
             atrial rates: 120-140bpm, ventricular escape rate: 40-60bpm
      

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