CARDIAC Flashcards
CHD
Congenital heart defects 1% of life births
errors in cardiac morphogenesis
septation, valve formation, pattering of the great vessels
development of the heart
primordia (lateral plate mesoderm)
primitive streak (ectoderm and endoderm layers)—symmetric mesoderm
body folding
“simple tube” contracts rhythmically (dilations-heart chambers; constrictions–partition between chambers)
major morphogenesis process done at 8 weeks post-conception
the tubular and looping heart
looping, convergence, and wedging
cardiac jelly
creates a distinct layer between the myocardium and endocardium
looping stages
“S” shape; “D” Dextro; “L” Levo…results in left ventricle on the right and right ventricle on the left
defects: mutation in ciliary ultrastructures)
convergence
process of proper orientation of the inflow (cranially) and outflow (ventral) tracks
defects: neural crest cell-associated diseases DiGeorge
wedging
parallel with looping and convergence; outflow thack rotates;
defects: conotruncal defects: tetralogy of Fallot, double outlet right ventricle
septation
begins with swelling of the extracellular matrix between the endocardium and the myocardium (AV junction, outflow track, primary atrial septum, ridge of the interventricular septum)
neural crest cells
contribute to the development of the heart and associated vessels: walls of the aortic arch arteries
separation of the aortic and pulmonary trunk
formation and maturation of the cardiac conduction system
defects: inflow anomalies and abnormalities of the aortic arch arteries
cardiac conduction system development
CCS
epicardium
relatively late-forming cardiac tissue, the outer layer of the heart; development of coronary vessels and valve development
cardiomyopathies
intrinsic disorders classified as hypertrophic, dilated, restrictive and arrhythmogenic
can myocardial cells divide after birth?
NO
primary heart field
L ventricle, portions of the AV canal
second heart field
(adjacent to neural crest cells) outflow tract, R ventricle, atrial formation
pulmonary vascular development
embryonic phase
pre-acinar vascular branching pattern present by 20th week GA
angiogenesis
budding, sprouting and branching of existing vessels to form a new ones
vasculogenesis
de novo organization of blood vessels produced by migration and differentiation of endothelial progenitor cells or angioblasts
hypoxic condition of fetal life support lung vascular growth T/F
TRUE
hypoxic intrauterine environment
HIF hypoxia inducible factors involved in angiogenesis, survival and metabolic pathways: VEGF (vascular endothelial growth factor); medicated by Nitric oxide
mediators of fetal pulmonary vascular tone
pulmonary hypertension is normal in fetal life
uses foramen ovale and ductus arteriosus to bypass the lungs
low oxygen environment,
low basal production of vasodilators (PgI2, and NO)
increased production of vasoconstrictors
pulmonary vascular transition
decrease in PVR at birth
close of foramen ovale
close of ductus arteriosus
longs inflation with gas and increase in oxygen tension
central vasodilators
NO
Prostacyclin
abnormalities of pulmonary vascular development
persistent pulmonary hypertension of the newborn (PPHN)
Congenital Diaphragmatic Hernia (CDH)
Alveolar Capillary Dysplasia (ACD)
Pulmonary Hypertension (PH)
PPHN
right to left extrapulmonary shunting of deoxygenated blood that produces hypoxemia
three categories:
1. lung parenchymal disease (MAS, RDS, pneumonia)
2. idiopathic
3. hypoplastic (CDH)
cases: antenatal NSAIDs, SSRI
genetics: downs syndrome
elective cesarean delivery, maternal DM, asthma, high BMI
perinatal asphyxia
oxidant stress
CDH
abnormal diaphragm development, herniation of abdominal viscera into the chest and variable degree of lung hypoplasia
ACD
interstitial lung disease that presents as severe PH and hypoxemia early in life
genetic defect of a pulmonary capillary bed
fatal
PH
extremely premature birth, associated with oligohydramnios
caused by BPD
pulmonary vein stenosis
Clinical therapy of PPHN
respiratory distress, labile oxygenation, differential saturation (higher in R hand) profound hypoxemia despite oxygenation and mechanical ventilation
usually in term
ECHO mandatory to rule out congenital heart disease
PPHN ECHO
right to left shunting:
foramen ovale, ductus arterious, left deviation of the intraventricular velocity, tricuspid regurgitant velocity, increase in R ventricular dilation
requires lung recruitment, optimization of right and left ventricular function, and maintenance of PaO2 between 60 and 80
PPHN management
normal temperature, electrolytes (calcium), glucose and intravascular volume
systemic BP at normal levels
maintain normal L ventricle function
PPHN management guidelines
iNO then ECMO OI more than 25
iNO for PPHN w/ parechymal lung disease
evaluate for developmental disorders: ACD or surfactant deficiency
Sidenafil, inhaled prostacyclin, IV milrinone
PPHN maternal factors
diabetes, high body mass index, smoking, use of SSRIs or NSAIDs, and caesarean section
PPHN postnatal factors
perinatal asphyxia, hyperoxia, hypoxia, infection, and lung inflammation
best timing for fetal ECHO
18-22 weeks
fetal myocardium
noncontractlie elements (60%)
fetal cardiomyocytes can divide
slow removal of Ca from troponin C(slower muscle relaxation)
equal R and L wall thickess
increased preload cases what?
fetal hydrops (cause by anemia, viral illness, significant arterial to venous malformations) caused by placental edema (AV malformations, sacroccygeal teratomas, TTTS)
what organ has the lowest vascular resistance in fetal circulation?
placenta
fetal indications caregories
fetal
maternal
genetics
what is the minimum for fetal ECHO
thorough two-dimensional imaging, color Doppler, and spectral Doppler examination of the four-chamber view, both arterial outflow tracts, three vessels and trachea view, and an assessment of pulmonary venous return
fetal pathology categories
structural anomalies (tx post) functional anomalies (tx post) rhythm disorders (tx prenataly)
