Cardiovascular Flashcards
Tetralogy of Fallot defects
VSD
Overriding aortic arch
Pulmonary stenosis/obstruction
Right ventricular hypertrophy
Tetralogy of Fallot embryonic cause
Incomplete rotation of conotruncus—leads to malalignment of conal and ventricular septum
Five T’s of cyanotic heart disease
Tricuspid atresia
Truncus
Transposition
Tetralogy of Fallot
TAPVR
Two genes responsible for cardiac left-right differentiation
Shh
Pitx2c
Vascular defects that present as congestive heart failure (include other findings with each)
- AVM—liver (hepatomegaly)
- AVM—cerebral (diminished pulses, pulmonary edema—like PDA but “steal” is up carotid)
- Vein of Galen aneurysm (cranial bruit/bounding carotid, irritability/seizures, high RA PO2 from highly oxygenated blood shunting thru aneurysm, DIC)
Gene responsible for RVOT development
Tbx1
Two cardiac abnormalities highly associated with 22q11
Tetralogy of Fallot
Interrupted aortic arch type B (most common type overall, 60% have 22q11 deletion)
(type B is after left carotid artery (before left subclavian))
Two things associated with supravalvar pulmonic stenosis
- Williams syndrome
- Congenital rubella
Milronone mechanism and indications
- Phosphodiesterase 3 inhibitor—increased cAMP
- Improved ventricular function
- Decreased peripheral vascular resistance
Indications: RV dysfunction, improving function in cardiac patients coming off bypass (especially if need decreased SVR)
What is the Delta wave and what’s it associated with?
Preexcitation of ventricles (a wave preceding the R)
(Preexcitation is via accessory pathway, causes WPW)
Antiarrhythmic drug classes and where they work on phases
I: active depolarization (Na block eg procainamide, lidocaine)
II and III: sustained depolarization phase (beta- and K-block, respectively eg propranolol, amiodarone)
IV: repolarization (Ca-block)
*Do not use Ca-channel blockers (verapimil) in neonates
Associations with Ebsteins anomaly
Lithium
Wolff-Parkinson-White and SVT (or RBB–think things that may be affected by a displaced node)
Very enlarged right heart on CXR
Starling forces
Hydrostatic: Pressure fluid (ie solvent) exerts outward from capillaries
Oncotic: Pressure solutes exert that pulls fluid into capillaries
Physiologic factors that close ductus arteriosus
1) increased PaO2
2) decreased prostaglandins (PGE2)
(Both these occur 2-2 sudden lung inflation at birth)
Mechanism of action in PDA closure for indomethacin or ibuprofen
Prostaglandin synthesis inhibition by cyclooxygenase enzyme (COX) inhibition (binds so arachidonic acid cannot)
Success rate equal (75%) between two medications
How do glucocorticoids impact ductus arteriosus closure
Potentiate its sensitivity to oxygen (which promotes closure)
Lack of maternal betamethasone is a risk factor for PDA
Name the three pathways that affect pulmonary vasoregulation
- Endothelin (think bosentan AKA Remodulin, endothelin antagonist)
- Nitric oxide (think iNO, sildenafil)
- Prostacyclin (think milrinone, epoprostenol AKA Flolan)
(NEJM.org)
What is the end effect of bosentan?
Endothelin receptor antagonist, preventing endothelin-receptor complex from causing endothelial constriction and proliferation
What is the mechanism of action of sildenafil?
Phosphodiesterase-5-inhibitor
Prevents breakdown of vasodilatory cGMP (nitric oxide pathway)
Mechanism of action of milrinone
Phosphodiesterase-3 inhibitor, prevents cAMP breakdown (prostacyclin pathway)
- Pulmonary vasodilation
- Reduces afterload (arterial relaxation)
- Improves myocardial [ventricular] function
What effects do corticosteroids have in relation to pulmonary hypertension
- Reduce reactive oxygen species
- Increase cGMP synthesis
- Reduce cGMP metabolism
* Net pulmonary vasodilation (via nitric oxide pathway)*
What characteristic of the blood vessels most significantly impacts blood flow?
Vessel diameter (AKA radius)
Think of Poiseuille’s Law–inverse, where because:
Q=P/R
Q=P x (πr4 / 8nL)
What are the main substrates of the 1) fetal and 2) adult myocardium?
- Fetal - glucose and lactate
- Adult - fatty acids
Characteristic cardiac findings in glycogen storage diseases
Short PR interval
Biventricular hypertrophy
Conotruncal lesions should make you think of what genetic syndrome?
22q11, AKA DiGeorge
Mechanisms of hydrocortisone on increasing blood pressure (four groups of action)
- Inhibits nitric oxide synthase (NOS) and prostaglandin release - inhibits vasodilation
- Increases Ca++ concentration - contractility
- Upregulates adrenergic receptors and decreases catecholamine metabolism - vasoconstriction and contractility
- Upregulates angiotensin-II receptors - vasoconstriction
Cardiac defects associated with elfin facies, open mouth, transient hypercalcemia
Supravalvar aortic OR pulmonic stenosis
(Rubella is also associated with supravalvar pulmonic stenosis)
Cardiac defects associated with Rubella
Patent ductus arteriosus (PDA)
Supravalvar pulmonic stenosis
Oxygenation index equation
OI= (what you’ve put in) / (what you get out)
(MAPxFiO2) / PaO2
OI>40 is considered the threshold for ECMO
How does PCO2 influence pulmonary vs cerebral blood flow
A low PCO2 vasodilates pulmonary vasculature
A low PCO2 vasoconstricts cerebral vasculature
Reason that patients with head injuries used to be hyperventilated, and patients with PPHN would be overventilated
What percentage of infants with BPD develop pulmonary hypertension
1/3
Reason to do screening echocardiography, and theoretically consider cardiac catheterization
The congenital heart defect variants known for a reverse saturation differential
dTGA with aortic coarctation
dTGA with pulmonary hypertension
Two ECG abnormalities seen in Pompe disease
Short PR interval
Bilateral ventricular hypertrophy
Can also have preexcitation (all from their hypertrophic cardiomyopathy)
Hydrocortisone ________ catecholamine metabolism
decreases
- So they “stick around” longer*
- It also decreases NOS expression and prostaglandin action*
The first- and second-line agents for fetal SVT
Digoxin and amiodarone
Digoxin first-line mainly 2-2 safety profile, while amiodarone’s 90% effective for AV reentry
Normal QRS axis for term neonates
+55 to +200
Remember it’s right-axis deviation that’s normal
Frequency of chromosomal abnormalities in fetus with congenital heart defects
1 in 8 fetuses
Most commonly the Trisomies (21, 18 and 13) or DiGeorge
The most common brain abnormalities in CHD
White mattery injury and infarction
Including on preoperative MRI
Four genes associated with HLHS
NKX2-5
GJA1
NOTCH1
HAND1
Sibling’s likelihood of ANY CHD with prior infant with HLHS is 22% (8% for HLHS in particular)
Most commonly affected gene in Long QT Syndrome (LQTS)
KCNQ1
Both LQTS and KCNQ1 have a _Q__
The typical timeframe for symptomatic hypertrophic cardiomyopathy 2-2 maternal diabetes to resolve
1 month
NeoReviews
The amount of desaturated hemoglobin needed for cyanosis
3-5g/dL
Since it’s an absolute amount, that’s why the higher your Hb the less desaturation’s needed to appear cyanotic (e.g. 80% saturated with a Hb 15 vs. 70% when Hb 10)
The risk of CCHD in siblings of a person with HLHS (hypoplastic left heart syndrome)
22% for any CHD, 8% for HLHS specifically
Metabolic side effects (usually transient) of epinephrine infusion
Lactic acidosis
Hyperglycemia
Hypocarbia (low HCO3)
In HLHS, the best echocardiographic way to assess adequate atrial communication (i.e. blood flow)
The most common cause of neonatal SVT (supraventricular tachycardia)–multiple names
AVRT (atrioventricular reentrant tachycardia OR reciprocating tachycardia)
“Orthodromic reciprocating tachycardia”
An accessory pathway that can bypass AV node; differs from the most common cause when older, which is AV_N_RT
