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)
Prostoglandin dependent CHD lesions types
too little pulmonary blood flow
too little systemic blood flow
Transposition of the great arteries TGA
results in systemic venous return with relatively low oxygen content directed to teh ascending aortal results in CNS and cardiac hypoxia
fetal heart failure is associated with what?
placental edema and resultant hypoxia
DX of causes of Hydrops Fetalis
immune cardiac twin-twin transfusion arteriovenous malformation diaphragmatic hernia\cystic hygroma
TTTS twin to twin syndrome
DONOR: volume depletion and nephrosclerosis
RECIPIENT: increased volume, vasoconstriction
PPHN inodilator
milrinone; improve left ventricular function and reduce pulmonary blood flow and oxygenation
Prostanoids PPHN
IV PGI2; with neonates concern about systemic hypotension and/or ventilation-perfusion mismatch
inhaled PGI2 produce transient pulmonary vasodilation and enhanced oxygenation
fetus circulation overview
placenta (oxygenated blood) to foramen ovale to left atrium
highly oxygenated blood: umbilical vein to ductus venosus to inferior vena cava through FO by Eustachian valve
two different output systems
systemic: of the LV
pulmonic: RV towards placenta
steps for performing fetal ECHO
segmental approach:
fetal position: right-left and cranial-caudal axis
fetal abdominal situs
morphologic markers
fetal rhythm abnormalities
ectopic beats
tachycardia
bradycardia
Ductus arteriosus
connection between the pulmonary artery and descending aorta; deoxygenated blood returning to th eright heart is diverted to the placenta for reoxygenation; excessive pulmonary blood flow causing diseases like RDS, BPD, NEC, IVH
what causes the PDA to close?
rapid postnatal increase in arterial oxygen tension; fall in PGE 2 from fetal placenta prenatal glucocorticoids dynamic closure 4 days anatomic closure 1 week
fetal PDA direction
right to left
newborn PDA direction
left to right
PDA clinical presentation
machinery murmur
increased precordial impulse
prominent arterial pulses (palms)
1000g +: decreased systemic arterial diastolic BP and increased pulse pressure
1000g -: reduction in diastolic and systolic BP withouth widened pulse pressure
PDA diagnostics
Doppler ECHO
BNP marker elevation (IVH risk and neurodevelopmental effects
xray: enlarged cardiac silhouette, pulmonary edema, nonspecific
consequences of ductal shunt on ECHO
left heart volume load, cardiac function, systemic hypoperfusion
PDA management
surgical ligation
indomethacin
NSAIDs ibuprofen/acetaminophen
indomethacin side effects
with glucocorticosteroids increase risk for bowel perforation
oliguria
NEC
ibuprofen PDA side effects
bilirubin displacement
ligation side effects
severe left ventricular disfunction and cardiorespiratory decompensation immediate post surgery
cyanotic heart defect: mixing dependent
D-Transposition of the Great Arteries (D-TGA)
aorta arises from RV, receives systemic deoxygenated blood
pulmonary artery arises from LV, receives venous oxygenated blood
deoxygenated blood recalculating the body
oxygenated blood recalculated the lungs
egg shaped heart
surgery: arterial switch operation
Cyanotic heart defect; restricted pulmonary flow ToF
tetralogy of Fallot (ToF)
large ventricular septal defect
infundibular and valve pulmonary stenosis
RV hypertrophy
large aorta overriding the ventricular septum
clinical presentation: RV outflow track obstruction determines the saturation, boot shaped heart
Cyanotic heart defect; restricted pulmonary flow TA
Tricuspid Atresia platelike tissue in place of the tricuspid valve with no direct communication between RA and RV
clinical presentation: cyanosis and murmur, hepatic enlargement,ECHO, ECG
surgery: bidirectional cavopulmonary anastomosis Glenn ot total cavopulmonary operation/Fontan
Cyanotic heart defect, restricted pulmonary flow PA/IVS
pulmonary atresia with intact ventricular septum
well-formed pulmonary annulus with a plate that obstructs outflow to complete absence of the valve
pulmonary flow depends only on PDA
clinical presentation: cyanosis, murmur; cardiomegaly
surgical: valvotomy
cyanotic heart defect: restricted pulmonary flow EA
Ebstein Anomaly
arrested delimitation of the leaflets during valve development; conduction abnormalities
clinical presentation; cardiomegaly
Cyanotic heart defect: complete mixing TAPVC/TAPVR
total anomalous pulmonary venous connection or return
all pulmonary being caring oxygenated blood drain into the systemic venous circulation rather than normally to LA
clinical presentation: symptomatic, xray: pulmonary edema, snowman sigh
cyanotic heart defect: complete mixing TA
trunks arteriosus
common origin of the aorta and pulmonary artery from a single arterial trunk
DiGeorge
clinical presentation: saturation in mid-80s%, murmurs, bounding pulses, increased pulse pressure
RX: diuretics and digoxin
cyanotic heart defect: variable physiology
Single Ventricle Anatomy
Hypoplastic Left Heart Syndrome (rx: provide adequate systemic blood flow and effective control of pulmonary blood flow)
double outlet RV (aorta and pulmonary artery both arise from RV
obstructive heart defects
Valvar aortic stenosis (murmur and click)
Aortic Coarctation and interrupted Aortic Arch (Turner, diminished femoral pulses and BP and O% differentials between the upper and lower extremities
Serial Obstructive Left heart defects
Valvar Pulmonary Stenosis (PS)
Shunting Lesions
Ventricular Septal Defect (murmur at left sternal border, oral diuretics
Atrial Septal Defect
Atrioventricular Septal Defect (trisomy21; murmur at the apex
PDA (machinery murmur, , significant L-R shunting,, wide pulse pressure and bounding pulses
Aortopulmonary Window
Situs
the development of morphologically right-side structures on one side of the body, and morphologically left-sided structures on the other side
solitus-normal
inverses-opposite side of the body
dextrocardia
base to apex axis of the heart is directed to the right side of the chest
mesocardia
apex is midline
Arteriovenous malformations
AVMs abnormal direct connection between arteries and veins via a network of vessels called the NIDUS that lack an intervening capillary bed
Galen malformation: cranial bruit, systolic ejection murmur
RX; milrinone, iNO, loop diuretics
hypertrophic cardiomyopathy
infants od DM moms
pericardial effusion
increased fluid within existing pericardial space, fetal hydrous, pericardial tamponade
cardiac tumor
rhabdomyoma
vascular rings and slings
cause compression on trachea, esophagus or both
respiratory difictulties) stridor or wheezing)
Marfan Syndrome
skeletal, ocular Cvm cutaneous, urologic, pulmonary manifestation, family HX
sinus node
initiation of cardiac electrical activity; posterior junction of the superior vena cava and RA
atropine and bradycardia
increases rate almost immediately, no change in HR if primary sinus node dysfunction
sinus arrhythmia
“respiratory” HR increase on inspiration, and decrease with expiration; Bainbridge reflex
change in rate no change in P-wave
premature atrial contractions
conducted, nonconducted, aberrantly conducted
“blocked” PAC- no QRS complex after P-wave
couplet two in the row
bigeminy every other
atrial ectopic tachycardia” three or more consecutive PACs with rate fatre than 120
exclude IV placement hat might cause this
Atrial Flutter
rate 300-600, ventricular way slower, sawtoothhhhh pattern
RX: cardioversion,
Supraventricular tachycardia
SVT
Wolff-Parkinson-White, Ebstein anomaly
1.atrial fib in the presence of an accessory pathway (adenosine usually contradicted)
2,concealed accessory pathway
3. atrioventricular nodal reentrant tachycardia, no true accessory pathway
200-300 BPM
RX: adenosine(0.1-0.4mg/kg), vagal stimulation (ice on face over 10-15 sec) or cardioversion
propranolol 4mg/kg/day
digoxin 4-5 mcg/kg
premature ventricular contractions
spontaneous depolarization of the ventricle myocardium resulting in an early or premature ventricular contraction
ventricular Tachycardia
RX:
- normal anatomy: no treatment needed
- 200-220 BMP use propranolol, or flecainide, aotalol, amiodarone
- very fast or incessant tachycardia: IV amiodarone or sotalol
“sine wave”
The hallmark feature of severe electrolyte or acid-base disturbances is a loss of delineation between the QRS complex and the T wave.
First degree atrioventricular block
manifested by prolongation of the PR interval on the ECG while each sinus or atrial beat reaches the ventricles PR longer than 160msec
second-degree atrioventricular block
some, but not all, sinus beats do not conduct to the ventricles. On ECG, this results in some of the P waves not being followed by a QRS complex “dropped QRS”
complete block
there is no conduction of sinus beats from the atria to the ventricles due to abnormality of the AV node or bundle of His or both bundle branches.
MOB has: systemic lupus erythematosus or mixed connective tissue disease, particularly Sjögren syndrome
long QT syndrome
mulitifaced genetic, torsades de pointes, syncopal episodes and seizures
SIDS?
torsades de Pointes RX
dc all meds causing prolonged QT interval
avoid amiodarone
Magnesium bolus and continuous infusion even if the serum magnesium level is normal.
Isoproterenol
Prostoglandin E 1 dosing
0.03mcg/kg/min up to 0.2mcg/kg/min
preload meds
loop diuretics: furosmide, bumetanide
thiazide diuretic: chlorothiazide
potassium sparing: spironolactone
afterload meds
milrinone
afterload-reducing, inotropic, and lusitropic (ventricular relaxing) properties
dobutamine (significant elevation of HR)
pulmonary overload: oxygen and iNO, sidenafil or bosentan
contractility
digoxin
dopamine and dobutamine
epinephrine
tet spells: hypercyanotic spells
ToF, dynamic subpulmonary obstruction of the right ventricular outflow
difference between fetal and newborn myocardial function?
neonate has the ability to increase cardiac output with increasing atrial pressures (preload)
aneuploidy CHDs
trisomy 13: conotruncal defects, septal defects, valvular anomalies
trisomy 18: septal and polyvalvular dysplasia
trisomy 21:
AV defect, and ventricular septal defect VSD
Turner syndrome: left-sided cardiac structures: aortich arch and valve abnormalities
Chromosomal deletions CHDs
Digeorge: conotruncal
Jacobsen syndrome: VDS and left sided obstructive defects
Williams Syndrome: supravalvular ourtic stenosis and pulmonary stenosis
VACTERL: VSD and atrial septal defect
Beckwith-Wiedemann Syndrome: cardiomegaly, PDa, and PFO; risk for developing cancers
Tof F
pulmonary artery stenosis, VSD overriding aorta RV hypertrophy "boot shaped" heart blue or pink ToF cyanotic/noncyanotic tet spells paroxysmal hypercyanotic episodes
