PREP 2019 Flashcards
When does ALCAPA typically present?
Between 1-4 months of age
Why are ALCAPA patients asymptomatic in early infancy?
Persistent elevation of the PA pressures promotes antegrade flow through the anomalous coronary artery
*Even though it is desaturated, this is usually enough to give O2 to LV
What causes symptoms to develop in ALCAPA?
- PVR falls, so the CPP also decreases
- This causes flow reversal in the coronary and leads to myocardial ischemia to the LV
- Ischemia leads to decreased LV function, papillary muscle dysfunction, MR and MI
How do infants with ALCAPA present?
Non-specific signs: Dyspnea, feeding intolerance, weight loss, irritability (especially with feeding… caused by angina due to increased O2 demand with feeds)
What is seen on CXR for ALCAPA?
Cardiomegaly from dilated LV
What is seen on the ECG in ALCAPA?
- Deep Q waves in I and aVL
- Repolarization abnormalities in precordial leads (V4-V6)
*Abnormalities in the ST segments aren’t consistently seen with this defect
Why is the diagnosis of ALCAPA from echo challenging?
- 2D images, LCA can appear to arise from aorta
- Need color Doppler to document origin of LCA from PA as well as flow reversal during diastole in the left coronary system
Besides the abnormal coronary origin, what else is often seen on echo in ALCAPA patients?
- Mod-severe MR with “chalk-stick” appearance to the papillary muscles
- Dilated LV with poor function
What causes MR in ALCAPA?
Ischemic injury to the LV papillary muscles
If ALCAPA can’t be diagnosed via echo, what are other options?
- CTA (cardiac gating to synchronize images to HR)
- Aortic root angiography in cath lab (gold standard for evaluating coronary origins)
*MRI can be used, but CTA is better in this age group
What is the differential diagnosis for ALCAPA?
DCM and viral myocarditis
What is the management for ALCAPA?
Surgery
*Supportive measures (inotropes, ventilation, etc) while awaiting definitive surgical repair
What medications are often required after ALCAPA repair?
PO heart failure therapy (to treat ongoing heart failure from ventricular dysfunction)
How long does the ventricular function take to normalize in patients after surgical repair of ALCAPA?
Several months
A loud crescendo-decrescendo systolic murmur that radiates to the carotid arteries, single S2 and delayed/diminished peripheral pulses suggest what?
Severe AS
In an asymptomatic patient, a cath peak to peak gradient above what results in the recommendation for aortic valvuloplasty?
50mmHg
In a symptomatic patient (angina, syncope, ischemic ECG changes at res or exercise), a cath peak to peak gradient above what results in the recommendation for aortic valvuloplasty?
40mmHg
What echo gradient better approximates a cath peak to peak gradient?
Mean Dopper-derived gradients (or peak gradients corrected for pressure recovery)
*vs. Peak instantaneous gradient
The 2014 AHA/ACC guidelines define severe AS as a Doppler velocity > what?
4M/sec
The 2014 AHA/ACC guidelines define severe AS a mean gradient > what?
40mmHg
What is the recommended management for severe congenital AS in infants, children and adolescents?
Balloon valvuloplasty
When might surgical valvotomy/repair be recommended for AS?
If there is significant AI with the severe AS
Why does medical management not help valvar AS?
It is a fixed obstruction
True or False: B-blockers are beneficial in valvar AS?
False- They are helpful with alleviated dynamic obstruction in HOCM, but not valvar AS
What is recommended to help with chronotropy in patients with moderate AS who want to participate in recreational activity?
Improved hydration
True or False: Exercise testing in asymptomatic AS is relative safe
True
True or False: Patients with symptoms provoked only by exercise testing are considered asymptomatic
False- Symptomatic even if the clinical history is equivocal
Why is exercise testing not recommended in symptomatic patients with severe AS?
Can precipitate syncope, v-tach and sudden death
What is one of the primary causes of hemoptysis in Fontan patients?
Persistant or new AP collaterals
What is considered a significant risk factor for AP collaterals in a Fontan patient?
Cyanosis
*The APCs can then lead to hemoptysis
True or False: Fontan completion if relatively protective against the formation of AP collaterals?
True- Patients left at Glenn are more cyanotic which leads to more APCs v. those with Fontan completion
Why do APCs tend to improve following Fontan completion?
Improved saturations
What causes persistent AP collaterals in Fontan patients?
- Mild Hypoxemia
- Abnormal/non-pulsatile flow to the PAs
True or False: Physical activity and exertion are risk factors for hemoptysis?
False- Hemoptysis tends to occur sporadically
What is the first line treatment for hemoptysis due to AP collaterals?
Cath with selective APC embolization
What is an option for recurrent hemoptysis due to AP collaterals?
Pulmonary lovectomy
What would be a reason to avoid an ACEi for an adolescent with HTN?
If they are sexually active and not using protection
True or False: B-blockers aren’t recommended as initial treatment for hypertension in children?
True- Due to potential adverse effect profile and lack of data to support long-term benefits in children
What would be the choice of anti-hypertensive agent for an adolescent who is sexually active?
CCB like amlodipine (avoid ACEi due to teratogenicity)
What are the 2 major classes of CCB?
- Dihydropyridine (smooth muscle selective)
- Nondihydropyridine (relative myocardium selective)
How do dihydropyridine CCB work?
-Block L-type Ca channels on vascular smooth muscle causing reduction in vascular resistance and arterial pressure
What type of drugs are amlodipine, felodipine, isradipine, nicardipine, nifedipine, nimodipine and nitrendipine?
Dihydropyridine CCB
What type of drugs are verapamil and diltiazem?
Nondihydropyridine CCB
What are the nondihydropyridine CCB (verapamil and diltiazem) typically used for?
Anti-arrhythmics
What are some side effects associated with CCB?
Flushing Headache Hypotension Edema Reflex hypertension
What are some side effects specific to the cardiac-specific nondihydropyridine CCB?
Negative effects on the SA node and AV node
Shouldn’t be used in patients with bradycardia or conduction abnormalities
What drug class should be considered as treatment for HTN in patients with contraindications to ACEi?
Dihydropyridine CCB
What are the 2 main types of CCB and what is their use?
- Dihyrdopyridine: HTN
2. Non-dihydropyridine: Anti-arrhythmic
Kartagener syndrome is a subgroup of what?
Primary ciliary dyskinesia (PCD)
Situs inversus totalis
Chronic sinusitis
Bronchiectasis
Kartagener
Primary ciliary dyskinesia is caused by a defect in what?
Proteins in cilia
True or False: There is considerable variation in the clinical presentation of primary ciliary dyskinesa?
True
When do most patients with primary ciliary dyskinesia present?
Childhood (but some don’t present until adulthood)
How is primary ciliary dyskinesia inerited?
AR
*Multiple genetic variants have been indentified
What feature must be present for the diagnosis of Kartagener?
Situs inversus
Situs inversus if found in what % of patients with primary ciliary dyskinesia?
50%
What syndrome can be seen in association with primary ciliary dyskinesia?
Heterotaxy
True or False: It is common for patients with situs inversus totalis and primary ciliary dyskinesia to have CHD?
False
True or False: It is common patients with heterotaxy and primary ciliary dyskinesia to have CHD?
True
True or False: No single test has been established as the definitive standard for the diagnosis of primary ciliary dyskinesia?
True
What are options in the workup of primary ciliary dyskinesia?
- Respiratory epithelial biopsy with electron microscopy
- Measurement of nasal NO
- High-speed videomicroscopy analysis of cilia
- Cell culture of ciliated cells
- Genetic testing
*Current recommendations don’t rely on 1 test, panel is required to confirm diagnosis
What is the most common cause of acquired CAD in children?
Kawaksaki
What is included in the recommendations for routine surveillance in Kawasaki patients?
- Echo in those with persistent coronary artery abnormalities
- Exercise or pharmacologic stress imaging with persistent coronary artery aneurysms
What are options for exercise or pharmacologic stress imaing in kids?
- Stress echo
- Stress with MR perfusion imaging
- Stress with nuclear medicine perfusion imaging
How is conventional stress testing in children performed?
Graded exercise on a treadmill or cycle ergometer (often combined with metabolic measurements of CO)
What is done to assess cardiac structural and/or functional response to exercise?
- Exercise echo
- CMR
What is done for exercise stress imaging in a young patient or someone who can’t exercise?
Pharmacologic stress test
How does a pharmacologic nuclear stress test work?
- IV injection of nuclear isotope and pharmacologic agent (adenosine, dipyridamole, dobutamine) to stress the heart in lieu of exercise
- Then obtain nuclear images (high radiation dose)
*Can use echo or CMR pharmacologic stress imaging as alternative to nuclear
What is a disadvantage of a pharmacologic nuclear stress test?
High radiation dose
List some potential indications for nuclear stress perfusion imaging in pediatrics
- History of Kawasaki disease
- Identification of transplant coronary artery vasculopathy
- Assessment of coronary artery insufficiency in d-TGA s/p ASO
- Assessment of coronary artery insufficiency following surgical coronary reimplantation for congenital anomalous origin of the coronary artery
What is indicated for children with persistent coronary artery aneurysms s/p Kawasaki?
- Exercise stress imaging or
- Pharmacologic stress imaging (if can’t exercise)
Why is nuclear medicine stress testing limited in pediatric?
Significant radiation exposure
Tachycardia with RBBB pattern, LAD and relatively narrow QRS (120-140msec)?
Fascicular ventricular tachycardia
True or False: You can have VA dissociation in fascicular ventricular tachycardia?
True
True or False: Patients with fascicular ventricular tachycardia can develop subacute onset of heart failure?
True
What medication is most likely to terminate fascicular ventricular tachycardia?
Verapamil
What are some other names for fascicular ventricular tachycardia?
Idiopathic left ventricular tachycardia
Verapamil sensitive ventricular tachycardia
Verapamil-sensitive left ventricular septal ventricular tachycardia
Belhassen tachycardia
*Also RBBB ventricular tachycardia or Purkinje-related ventricular tachycardia (less specific)
What is a reentrant tachycardia that involves the fascicles of the LBB?
Fascicular ventricular tachycardia
What age and what gender is fascicular ventricular tachycardia most common in?
Teenagers and young adults
Male
True or False: Fascicular ventricular tachycardia is monomorphic and generally well tolerated?
True
*Can be paroxysmal or incessant, can present with tachycardia induced cardiomyopathy
Describe the circuit in fascicular ventricular tachycardia
- Orthodromic limb of slowly conducting myocardium with verapamil sensitivity
- Retrograde limb involving the Purkinje network
Describe the appearance of left posterior fascicular ventricular tachycardia
RBBB pattern
LAD
(90% cases)
Describe the appearance of left anterior fascicular ventricular tachycardia
RBBB
RAD
(10% cases)
Describe the appearance of high fascicular ventricular tachycardia
Narrow QRS
Normal axis
(<1% cases)
V-tach with RBBB and LAD pattern?
Left posterior fascicular ventricular tachycardia
True or False: In general, fascicular ventricular tachycardia doesn’t cause acute hemodynamic compromise unless cardiomyopathy is present
True
What is the short term management of fascicular ventricular tachycardia?
IV verapamil- Slows and terminates rhythm
What do you need to be cautious about before giving IV verapamil in fascicular ventricular tachycardia?
That there isn’t significant myocardial dysfunction
Besides verapamil, will any other medications terminate fascicular ventricular tachycardia?
- Adenosine and B-blockers, but less likely to work
- Digoxin, No
- Class I (procainamide) or class III (amiodarone) medications may work, but aren’t usually needed
What should be done for fascicular ventricular tachycardia associated with hemodynamic compromise or is refractory to other treatment?
DC Cardioversion
What is the long-term management of fascicular ventricular tachycardia?
-PO verapamil or -Class I or III agents (Flecainide, sotalol, amiodarone) or -RF ablation (typically curative)
Ventricular tachycardia with a RBBB pattern, LAD and relatively narrow QRS (120-140msec) should raise suspicion for what?
Fascicular ventricular tachycardia (especially in a structurally normal heart)
Short term termination and long-term suppression of fascicular ventricular tachycardia are achieved with what?
Verapamil (IV for termination, PO for long-term)
What is the most common cause of sudden cardiac arrest in children in the US?
HCM
*Accounts for over 1/3 of cases
What is the second most common cause of sudden cardiac arrest in children in the US?
Anomalous coronaries
Which is more concerning, an anomalous RCA from the left sinus or anomalous LCA from the right sinus?
Anomalous left
What is a concern when there is a severely dilated sinus of Valsalva and ascending aorta (>5cm in adults)?
Dissection leading to aortic rupture
How would an aortic dissection present?
Chest pain, collapse, hemopericardium, hemothorax
True or False: Although DCM can cause ventricular arrhythmias, it is an uncommon cause of SCA?
True
What is on the differential diagnosis for sudden cardiac arrest?
HCM
Coronary anomalies
*Others: Other cardiomyopathies (DCM), myocarditis, ARVC, CAD, AS, commotio cordis, ion channelopathies (LQTS)
What is the most common gene mutation in patients with primary pulmonary HTN?
BMPR2 (bone morphogenetic protein receptor II)
- Mutations in 10-40% of cases of idiopathic pulmonary HTN
- Familial pulmonary HTN, frequency increases to 70%
How is idiopathic pulmonary hypertension diagnosed?
When the results of a diagnostic evaluation for known causes of pulmonary hypertension are negative
Childhood presentation of pulmonary HTN is commonly associated with what?
CHD
Lung disease
*Need to rule out rare causes like connective tissue disease, liver disease or thromboembolic disease
Mutations in ALK1 (activin-like kinase type 1) are associated with what?
Hereditary hemorrhagic telangiectasia: Telangiectasias, epistaxis, cyanosis
Mutations in GBA (B-glucocerebrosidase) are associated with what?
Gaucher disease: Lysosomal storage disease with AR inheritance
*May get pulmonary HTN if ILD is present
Variations in HLA-DRB1 have been associated with increased risk for developing what?
Autoimmune disorders: Addison disease, MS, RA, T1DM, Sarcoidosis
What is the primary pulmonary HTN gene?
BMPR2 (bone morphogenetic protein receptor II)
The hemodynamic effects of an ASD are determined by what?
- Size of defect
- Compliance of LV and RV
L-R shunting across an ASD cause dilation of what?
Right heart
High Qp:Qs and resultant right heart dilation due to ASD are typically seen in what patients?
Those with moderate-large defects that occur in patients with low PVR (results in highly compliant RV that favors L-R shunting)
What would you see clinically in someone with an ASD, pulmonary vascular disease, stiff RV or elevated RVSP?
Desaturation due to R-L shunting
Why would a patient with a non-compliant LV or LVOTO be more likely to have a hemodynamically significant shunt across an ASD?
Elevated LA pressure
*Similar in situations with LA volume overload, like a VSD or nonrestrictive ductal shunt
Why do ASDs allow smaller volume shunts than VSDs of the same size?
Because atria are low-pressure chambers
True or False: In patients with normal hemodynamics, there is only a small pressure gradient between the LA and RA?
True
- Compliances assumed to be fairly equivalent
- Why atrial compliance doesn’t influence hemodynamic effects of an ASD (as much as size of defect or ventricular compliance)
Isolated congenital MR is most often due to what?
Dysplastic MV
Perinatal cardiomyopathy
In children >1 year, what are some causes of mitral regurgitation?
- Acute rheumatic fever
- Myocarditis
- Endocarditis
- Cardiomyopathy
- Kawasaki disease
- Coronary artery anomalies
- Collagen vascular disease
- Trauma to valve or chordae
What are some hemodynamic sequelae of severe MR?
- LV dilation
- LA enlargement
- Elevated pulmonary venous pressures
- Pulmonary edema
- Pulmonary HTN
How do infants with severe MR present?
CHF- Increased work of breathing, poor weight gain, FTT
What causes the CHF symptoms in an infant with severe MR?
Pulmonary edema due to LA HTN and decreased CO
True or False: Ventricular function is usually preserved in the short/intermediate term in severe MR?
True
*Although patients may eventually develop ventricular dysfunction and pulmonary HTN
What is the initial treatment of congenital MR?
Medical management:
- Diuretics (Lasix): Treat pulmonary edema and decrease WOB
- Maximize calories
- ACEi: Not recommended in adults, but can be used in small children
When is surgery considered for congenital MR?
When maximal medical therapy has failed
Why is MV repair in congenital MR challenging?
- Often unsuccessful or creates MS
- Replacement is hard because smallest mechanical valve is 15mm and larger than average annulus in infants… often has to be placed in the supra-annular position in the LA
Patients with progressive CHD or end-stage cardiomyopathy secondary to congenital MR may require what?
Heart transplant
Mechanical circulatory support with VAD
What is often seen on CXR in a neonate with ToF absent PV?
Cardiomegaly
Air trapping
Dilated proximal branch PAs
What is seen on CT in a neonate with ToF absent PV?
- Markedly dilated proximal branch PAs distal to a “waist” representing the plane of the rudimentary PV leaflets
- Tracheal narrowing
- Compression of mainstem bronchi on side of arch (between dilated PA and descending Ao)
- Differential air trapping (due to bronchial compression)
ToF absent PV occurs in what % of ToF patients?
3-6%
The rudimentary PV tissue in ToF absent valve is associated with the prenatal development of what?
- Severe PI
- Marked dilation of the proximal branch PAs
- Mild-mod PS/obstruction
What form of CHD should you consider with absence of the ductus arteriosus?
ToF Absent PV
*Absence of ductus may contribute to the pathogenesis of the condition
ToF absent PV is association with what genetic condition in 20-25% of cases?
Chromosome 22 microdeletion
*Others as well… genetic testing should be done as part of perinatal testing in these patients
What is seen on fetal echo in ToF absent PV?
- Severe PI
- Marked PA dilation
- Typical overriding aorta/VSD
What can result in utero from the severe PI in ToF absent PV?
- Fetal CHF
- Hydrops fetalis
- Fetal demise
Besides a fetal echo, what other testing can be done to help risk stratify in ToF absent PV?
Fetal MRI
- Assess lung volumes
- Assess potential for perinatal pulmonary obstruction
What causes the severe respiratory distress that can be seen in ToF absent PV?
- Bronchial compression (from dilated/pulsatile branch PAs and right arch if present)
- R-L shunting through VSD due to presence of elevated pulmonary resistance
What can be done for a neonate with severe respiratory distress due to ToF absent PV?
- Ventilator with PPV
- Prone (decreases severity of bronchial compression/air trapping)
*Some may need ECMO or early surgery
True or False: Neonates with ToF absent PV may have hypoplasia of distal branch PAs beyond the regions of marked dilation?
True- Persistent desaturation due to inadequate PBF
True or False: Some neonates with ToF absent PV can have surgery at a time similar to classic ToF?
True- some have mild symptoms and don’t need significant cardiorespiratory support
What is the characteristic murmur in ToF absent PV?
Harsh to-fro murmur of PS/PI
True or False: PGE is indicated in ToF absent PV?
False- Typically no ductus, so PGE won’t work
What are important ventilator management strategies in ToF absent PV?
- Increased PPV
- Prone position (improves airway compression for dilated/pulsatile branch PAs)
When should children be started on medications for HTN?
- Remain hypertensive despite trial of lifestyle modifications
- Symptomatic HTN
- Stage 2 HTN w/o clearly modifiable factor (obesity)
- Any stage HTN with CKD or DM
What are the cutoffs for treatment of LDL after 6 months of lifestyle modifications are attempted?
- LDL >190
- LDL >160 + 1 (FHx stroke, MI, SCD, 1 high risk factor or 2 moderate risk factors)
- LDL >130 + 1 (2 high risk factors or 1 high risk factor +2 moderate risk factors)
What constitutes a + FHx in terms of dyslipidemia risk?
MI, angina, coronary artery bypass graft/stent/angioplasty, SCD in parent, grandparent, aunt or uncle (< 55 men and <65 in women)
What are the high-level risk factors in terms of dyslipidemia risk?
- HTN requiring drug therapy (BP >99th% + 5mmHg)
- Current cigarette smoker
- BMI at or >97%
- High risk conditions: DM1, DM2, chronic renal disease, ESRD, post-renal transplant, post orthotopic heart transplant, Kawasaki with current aneurysms
What are the moderate-level risk factors in terms of dyslipidemia risk?
- HTN not requiring drug therapy
- BMI at or >95%, but <97%
- HDL <40
- Moderate risk conditions: Kawasaki disease with regressed coronary aneurysms, chronic inflammatory disease (SLE, juvenile RA)
- HIV
- Nephrotic syndrome
True or False: History of cancer and chemotherapy may impact the assessment of lipids in children
True- Certain chemotherapeutic agents may be a secondary cause of elevated lipid levels
True or False: History of cancer and chemotherapy are considered independent risk factors which influence therapeutic decisions regarding HLD?
False
List potential side effects of ACEi
- Bradykinin-induced cough (10% of adults, less common in kids)
- Elevated K (especially when given with other drugs that raise K or with decreased GFR)
- Hypotension
- Neutropenia
- Angioedema
- Skin reactions
What would be a concern for use of an ACEi in someone with severe asthma?
Potential for bradykinin-induced cough to exacerbate bronchospasm and asthma symptoms
What are some specific side effects/problems with captorpil?
- Adverse effects to the immune system (subacute cutaneous lupus erythematosus, drug induced lupus)
- Captopril-associated neutropenia may not be reversible in patients with collagen vascular disorders
How does carvedilol work?
Non-selective B-blocker with a-blocking properties
True or False: Carvedilol use can affect pulmonary function tests
True
True or False: B-blockers like atenolol or propranolol have been associated with a 5-10% reduction in FEV1?
True, but patients with mild asthma may still tolerate a B-blocker
How do ARBs work?
Block formation of angiotensin II
True or False: ARBs can still cause cough and angioedema, just not as often as ACEi?
False- The bradykinin adverse effects of ACEi (cough, angioedema) don’t occur with ARBs
Lorsartan is often used in patients with HTN and what other issue?
LVH (LIFE, Losartan Intervention for Endpoint Reduction) study showed atenolol to be inferior to losartan in the treatment of HTN and LVH
ACEi and ARBs are contraindicated in what circumstances?
- Pregnancy
- Severe renal failure
- Hyperkalemia
- Renal artery stenosis
- Severe aortic stenosis
- Obstructive cardiomyopathy
Besides ARBs, what other drug category are often used with good results in adults with HTN and asthma?
CCB
What produces an ejection click?
Sudden augmented distension of the great vessel wall when a normal volume of blood is ejected under high velocity and pressure
What happens to the timing of a systolic ejection click with more severe stenosis?
It moves earlier in systole until it merges with S1
What 3 things can help to differentiate the degree of PS by auscultation?
Timing of the click
Description of S2
Duration of systolic murmur
What does inspiration do to P2 normally?
Delays it
What causes the normal delay in P2 with inspiration?
Increase in RV ejection time
Reduced impedance of pulmonary arterial vascular ved
Describe the timing of the murmur in mild PS
Short
Peaks at or before mid-systole
Ends well before the aortic closure sound
Describe the timing of the murmur in severe PS
Extends beyond the aortic closure sound (which may become inaudible)
Split S2 may not be appreciable
What degree of PS will have a prominent RV precordial impulse and thrill at the LUSB?
Severe
Why might a critical PS baby have a soft systolic murmur across the PV?
Low cardiac output
What would cause a holosystolic murmur at the LLSB in critical PS in a neonate?
TR
What causes cyanosis in critical PS?
R-L atrial shunting
What is a classic exam findings in a large secundum ASD or sinus venosus ASD?
Widely split S2 that doesn’t vary with respiration and has normal intensity of both aortic and pulmonary components
What causes a fixed split of S2 in ASD?
During expiration, the decrease in systemic venous return is matched by an increase in pulmonary venous return and L-R shunting across the ASD
What is different about S2 in a large ASD versus PS?
ASD: Wide and fixed splitting of S2
PS: Widely split S2 that maintains normal respiratory variation
What causes a low-frequency ejection murmur in an ASD at the LUSB?
Increased flow across the pulmonary valve
What is the vascular junction that bridges the umbilical venous circulation to the floor of the RA?
Ductus venosus
How do you find the ductus venosus on fetal echo?
Search for the region of color aliasing within the body of the liver
Describe normal flow in the ductus venosus
Entirely antegrade
Relative reduction in flow velocity during atrial contraction
What does the normal antegrade flow pattern with relative reduction in flow during atrial contraction in the ductus venosus reflect?
The pressure gradient between the ductus venosus and RA
Reduced flow velocity during atrial contraction in the ductus venosus reflects what?
Blunting of forward flow because of elevated RA pressure (absent A-wave)
*Reversal of flow with atrial contraction reflects more advanced disease
In a fetus with a structurally normal heart, what does an abnormal ductus venosus Doppler mean?
Elevated RA pressure and/or poor RV compliance… sign of fetal compromise
When would reversal of flow in the ductus venosus with atrial contraction be expected?
Fetuses with right-sided obstructive CHD
*If the RA pressure is elevated due to right heart inlet and/or outlet obstruction (tricuspid atresia, PA/IVS), flow reversal with atrial contraction is anticipated and “normal” for the underlying physiology
Would you expect flow reversal in the ductus venosus in PA-VSD?
No- Even though there is right-sided outlet obstruction, there is decompression of flow/pressure through the interventricular communication which minimizes the potential for flow reversal
What does flow reversal in the pulmonary veins suggest?
Left atrial hypertension
Fetuses with what type of CHD can have flow reversal in the pulmonary veins?
HLHS and restrictive atrial septum (due to LA hypertension)
*Degree of flow reversal varies based on the severity of the LA outlet obstruction
True or False: Isolated TAPVR is one of the most difficult lesions to detect prenatally
True
What are findings on fetal echo with isolated TAPVR?
- Lack of visible pulmonary venous connections back to LA
- Presence of descending venous channel in abdominal views (can get anomalous venous connection to ductus venosus, spectral Doppler would show significant turbulence)
What is DORV with subpulmonary VSD and CoA called?
Taussig-Bing anomaly
Transposition-type DORV
*20% of cases of DORV
What forms the base of the interventricular communication in DORV?
The limbs of the septomarginal trabeculation (or septal band)
What is the inner curvature of the heart (ventriculo-infundibular fold) between?
The AV and semilunar valves
The portion of the ventriculu-infundibular fold between the mitral and aortic valves exists as what in the normal heart v. DORV?
- Normal heart: Fibrous remnant
- DORV: Muscularized (suboartic conus)
What does the ventriculo-infundibular fold between the mitral and aortic valve form in DORV?
Part of the roof of the interventricular communication (often described as the subaortic conus
What is the outlet septum?
Muscular or fibrous portion of the ventricular septum that is between the 2 semi-lunar valves
What determines the relationship of the interventricular communication relative to the great vessels?
Rotation of the conus and thus great vessels determines the position of the outlet septum relative to the limbs of the septal band and thus relationship of interventricular communication relative to great vessels
In transposition type DORV, what is the position of the great arteries?
d-malposed
In transposition type DORV, the caudal or posterior-inferior limb of the septal band is attached to what?
Outlet septum
What can cause subaortic obstruction in transposition type DORV?
Malalignment of the outlet septum
Subaortic obstruction due to malalignment of the outlet septum in DORV is also associated with what?
Aortic arch obstruction
Which is more common, DORV with a subpulmonary VSD or DORV with a subaortic VSD (+/- PS)?
DORV with subaortic VSD
In DORV with a subaortic VSD, the outlet septum is attached to what?
Cranial limb of the septal band
In what type of DORV is the outlet septum not attached to either limb and usually a fibrous remnant rather than a muscularized portion of the septum?
DORV with doubly committed VSD
True or False: DORV with a uncommitted/remote VSD is uncommon?
True- The interventricular communication closes
What finding occurs in the setting of transposition physiology and aortic arch obstruction?
Reverse differential cyanosis
*Upper body has a lower SpO2 than lower body
Describe what causes reverse differential cyanosis as seen in DORV with subpulmonary VSD and CoA?
- Upper body gets deoxygenated blood that streams preferentially from RV to aorta
- Lower body receives oxygenated blood that streams preferentially from LV, through VSD to PA, then across PDA to desc AO
True or False: Reverse differential cyanosis confirms the presence of a PDA?
True- Close of the PDA in this physiology leads to decreased flow to the lower body and similar low SpO2 in the upper/lower body
Anterior deviation of the conal septum in DORV leads to what?
Subpulmonary stenosis
True or False: DORV with subpulmonary stenosis (anterior deviation of the conal septum) + aortic arch obstruction is unusual?
True
Patients with DORV and a subaortic VSD have physiology similar to what?
ToF- Often have pulmonary or subpulmonary stenosis
What type of patients can anomalies in pulmonary venous drainage be seen in association with DORV?
Heterotaxy
Reverse differential cyanosis with low SpO2 in the upper body and higher SpO2 in the lower body is seen in what physiology?
Transposition + Arch obstruction
DORV with a subpulmonary VSD is associated with what 2 things?
Transposition physiology + CoA
What is the incubation period for Lyme diease?
7-14 days
Describe Stage 1 of Lyme Disease?
Localized with classic bull’s-eye rash at site of tick attachment (painless and non-pruritic)
-Also have fever, malaise and regional lymphadenopathy
What is Stage 2 of Lyme disease?
Early disseminated disease- May manifest itself in any body system
What is a notable skin lesion seem in disseminated Lyme Disease?
Erythema migrans
What are some of the persistent symptoms seen in stage 3 Lyme disease?
Localized scleroderma Prolonged arthritis Gait ataxia Chronic encephalomyelitis Keratitis Fatigue
Do long-term antibiotics help with Stage 3 of Lyme disease?
No- these symptoms persist despite clearance of the infection and may last weeks-months
What are the cardiac manifestations of Lyme disease?
AV nodal block
Myopericarditis
Pancarditis
What % of patients with Lyme disease get cardiac manifestations?
4-10%
What is the most common type of heart block in Lyme disease?
1st degree (higher grades like 2nd/3rd degree only occur in 1% of patients)
How is early localized Lyme disease (without neurologic involvement or advanced AV nodal block) treated?
PO doxycycline, amoxicillin or cefuroxime for 10-21 days
What is the preferred parenteral antibiotic in Lyme disease?
Ceftriaxone
How is 1st degree AV block with a PR interval <300msec treated in Lyme disease?
Outpatient with PO antibiotics
What heart findings seen in Lyme disease should be monitored in the hospital and treated with parenteral antibiotics?
- 1st degree AV block with a PR interval of >300msec
- 2nd degree AV block
- 3rd degree AV block
True or False: Central or peripheral nervous system involvement with Lyme disease (except for cranial nerve palsy) should be treated with parenteral antibiotics?
True
What type of medication is tadalafil?
Phosphodiesterase-5 inhibitor
What are symptoms of idiopathic pulmonary HTN?
Dyspnea with exertion Intermittent cyanosis Syncope Chest pain Sudden death
What is the gold standard for the evaluation of pulmonary HTN?
Cath
What are the first-line treatments for an acute pulmonary hypertensive crisis?
O2
iNO
How does iNO work?
- Activates guanylyl cyclase
- Leads to production of itnracellular cGMP
- cGMP causes smooth muscle relaxation of pulmonary vasculature
If an acute pulmonary hypertensive crisis isn’t responding to O2 or iNO, what can be used next?
IV prostacyclins (epoprostenol or treprostinil)
How do the prostacyclins work (epoprostenol or treprostinil)?
- Prostaglandin analogs that cause direct vasodilation in all vascular beds (including pulmonary vasculature) via adenylate cyclase and cAMP
- Also potent endogenous inhibitors of platelet aggregation
What is the half life of epoprostenol?
6 minutes
What is the half life of treprostinil?
4 hours
What forms does treprostinil come in?
IV, subcutaneous, inhaled
What are the 4 classes of medications used in the management of chronic pulmonary HTN?
- Phosphodiesterase 5 inhibitors
- Endothelin receptor antagonists
- CCB
- Prostacyclin analogs
What are examples of phosphodiesterase-5 inhibitors?
Tadalafil and sildenafil
How do phosphodiesterase-5 inhibitors work (sildenafil and tadalafil?
- Inhibit phosphodiesterase-5
- cGMP levels increased in smooth muscle cells (prompts relaxation and vasodilation)
What is a common side effect of the phosphodiesterase-5 inhibitors?
Hypotension (effects not limited to just pulmonary vasculature)
What forms does sildenafil come in?
IV and PO
What forms does tadalafil come in?
PO only
What drugs are considered 1st line chronic treatments for idiopathic pulmonary HTN in children?
Phosphodiesterase-5 inhibitors
What are examples of endothelin receptor antagonists ?
Bosentan and ambrisentan
How do endothelin receptor antagonists work?
-Competitive antagonists of the endothelin receptors in the lung (ETa and Etb, slightly higher affinity for ETa)
- Stimulation of endothelin receptors increases levels of itnracellular inositol triphosphate (IP3) via Gq protein coupling
- Increased intracellular IP3 levels cause increased Ca release from sarcoplasmic reticulum and smooth muscle contraction or vasoconstriction
- Inhibiting the endothelin receptor prevents increased intracellular IP3 levels and promotes pulmonary vasodilation
When using a CCB for pulmonary hypertension, you should choose one from which family?
Benzothiazepine
Why should you pick a CCB from the benzothiazepine family when treating pulmonary HTN?
Relatively selective for vascular calcium channels
How do CCB work in pulmonary HTN?
-Prevent egress of Ca from SR and prevent vasoconstriction/promote vasodilation
True or False: Patients should be tested for vasoreactivity to CCB in the cath lab prior to initiation?
True
True or false: Coronary artery fistulas have equal distribution between male and female patients?
True
What are symptoms from a coronary artery fistula determined by?
Fistula location and size
What are possible problems associated with a coronary artery fistula?
- CHF due to L-R shunting (poor growth, tachypnea, tachycardia)
- Coronary steal and myocardial ischemia (irritability, fussiness, poor color with feeds)
- Endocarditis (SBE prophylaxis not indicated)
What is the most likely presenting symptoms for an infant with a large coronary artery fistula?
CHF
What is the most severe form of PAH?
Eisenmenger syndrome
What causes Eisenmenger syndrome?
- Intra or extracardiac shunt lesions with large/chronic L-R shunting that leads to progressive pulmonary vasculopathy
- High flow/pressure from shunts can induce pulmonary vascular endothelial damage which causes release of growth factors that induce smooth muscle hypertrophy and proliferation with neointima formation
How does endothelial dysfunction contribute to pulmonary HTN?
-Causes increased vascular ton from imbalance between vasoconstrictors and vadosilators
Endothelin-1 and thromboxane do what?
Vasoconstrict
NO and prostacyclin do what?
Vasodilate
The activation of the endothelin system contributes to what?
Pulmonary vasoconstriction and remodeling
True or False: Pulmonary arteriolar remodeling caused by medial hypertrophy can be reversible in the early stages?
True- becomes irreversible with disease progression
When what proportion of the pulmonary vascular bed is compromised does pulmonary hypertension ensue leading to R-L shunting and Eisenmenger syndrome?
2/3
True or False: Children with CHD who undergo early surgical repair typically do not develop advanced pulmonary vasculopathy?
True
Determining the feasibility of surgical repair of an adult patients with CHD with PAH requires what?
Cath: Need PVR, PVR:SVR and acute response to vasodilators
PVR > what is considered prohibitive for surgical repair of CHD?
> 8-10 WU/m2
A PVR:SVR > what is considered prohibitive for surgical repair of CHD?
> 0.5
What medication is considered a class IA therapy for symptomatic adults with Eisenmenger syndrome?
Bostenan
*Sildenafil and IV prostacyclin are being studied with encouraging results, but bosentan is recommended first line
What is often used as a 2nd line disease targeting therapy for symptomatic adults with Eisenmenger syndrome after bosentan?
Phosphodiesterase 5 inhibitors
Besides vasodilator therapy, what are 2 other important aspects of management for adults with Eisenmenger syndrome?
- Treatment of “relative anemia” (to hypoxia)
- Endocarditis prophylaxis
Which is preferred in patients with pulmonary hypertension secondary to CHD, PO or IV vasodilators?
PO- IV associated with frequent complications
PO CCB are used for what types of PAH?
Idiopathic or familial
Why are CCB not routinely used in Eisenmenger syndrome?
Negative inotropic effects
Systemic vasodilation
ToF accounts for what % of CHD cases?
10%
Complete AVC defects account for what % of CHD cases?
2-9%
What % of AVC defect patients have concurrent ToF physiology?
6-10%
The presence of coronary abnormalities in ToF is what?
5-7%
What coronary anomaly is seen in up to 4% of ToF patients?
LAD or and accessory LAD from RCA
How does a coronary branch crossing the RVOT alter the surgical approach in ToF?
With a crossing coronary, would pursue an RV-PA conduit instead of a transannular patch
What are the 2 surgical approaches to ToF?
- Valve sparing technique (surgically remove the infundibular stenosis and spare the valve)
- Transannular patch repair
What are key components to image for ToF surgery planning?
- Coronary artery anatomy
- Common AV valve morphology
- Number/location of VSDs
- RVOT anatomy
What are the 2 causes of supravalvar AS?
- Discrete narrowing at STJ
- Long segment narrowing in ascending aorta
Patients with supravalvar aortic stenosis generally have what gene defects?
Elastin arteriopathy (defect in the elastin gene)
7q11.23 microdeletion?
Williams
The 7q11.23 microdeletion seen in Williams syndrome includes what gene that results in some of the cardiac manifestations?
Elastin gene
Slow growth, feeding difficulties, periorbital edema, developmental delay, hypercalcemia, supravalvar aortic stenosis?
Williams syndrome
True or False: The abnormalities in elastin that lead to the arteriopathy which causes supravalvar aortic stenosis in Williams syndrome can cause narrowing in other large arteries throughout the body?
True
What are some other arteries which can have narrowing besides supravalvar aortic stenosis in patients with defects in the elastin gene (Williams syndrome)?
- Pulmonary arteries (40%)
- Coronary arteries (Ectasia, ostial obstruction from webs or fibrous ridges)
- Thoracic aorta (middle aortic syndrome)
- Abdominal aorta
- Head an neck vessels
- Mesenteric arteries
- Intracranial arteries
What is stenosis of the thoracic aorta called?
Middle aortic syndrome
What is middle aortic synddrome?
Narrowing in the aorta distal to the head vessels
What patients can get middle aortic syndrome?
Williams
How does middle aortic syndrome present?
HTN in the upper extremities with normal or low BP in lower extremities
What causes a widened pulse pressure and increased systolic BP in Williams patients?
Abnormal aortic distensibility
What often results from streaming of the high-velocity jet in supravalvar aortic stenosis?
Coanda effect
What is the Coanda effect?
Asymmetric jet in the aorta that adheres to the wall and preferentially streams into one of the head an neck vessels (usually innominate and right subclavian artery)
How does the Coanda effect present?
Blood pressure difference between the upper extremities (Right > Left)
What cause of HTN should you consider in patients with William’s syndrome?
Renal artery stenosis
True or False: Renal artery stenosis is often seen in association with middle aortic syndrome?
True
What BPs are elevated in bilateral renal artery stenosis?
All 4
What vital signs should be routinely measured in patients with Williams syndrome and other types of elastin arteriopathies?
4-extremity BP
True or False: Sinus node dysfunction occurs frequently in the post-operative period after Fontan palliation?
True
When you have a junctional rate that is faster than an atrial rate, does this imply AV block?
Not necessarily
What is the preferred mode of pacing to start with sinus node dysfunction following surgery?
AAI
Why is AAI pacing the preferred mode to start with for sinus node dysfunction following surgery?
- Provides AV synchrony
- Provides HR support
- Uses patients own conduction system
- Avoids uncoordinated ventricular contraction seen with ventricular pacing
What are indications for temporary pacing following surgery?
- Sinus node dysfunction (HR support)
- Slow junctional rhythm (HR support and AV synchrony)
- JET (AV synchrony)
- AV block
- Reentrant atrial tachycardia or AVRT (pace termination via rapid atrial pacing)
What is rapid atrial pacing used for in the post-operative period?
Terminate reentrant atrial or AV reciprocating tachycardias
What are the 2 pacing modes that can be used for post-operative heart block?
- VVI (adequate ventricular escape)
- DDD (adequate HR and AV synchrony)
*DDD usually preferred, but VVI can be used if AV synchrony isn’t needed for adequate hemodynamics and/or to monitor for return of intrinsic AV conduction
What pacing is preferred for sinus node dysfunction, junctional rhythm, or junctional tachycardia if the patient’s intrinsic AV conduction is intact?
AAI
What is preferred pacing mode for post-op AV block?
DDD
*VVI can be used in certain circumstances
80-90% of double chambered RV’s are associated with what?
VSDs (usually perimembranous)
What % of patients with VSDs have associated cardiac lesions?
50-60%
Acquired defects associated with VSD seen at late follow-up often relate towhat?
Outflow tracts (development of RVOTO or LVOTO)
What is the cause of a double chambered RV?
Anomalous muscle bands that separate the RV into a proximal high-pressure chamber and distal low-pressure chamber (resultant muscular obstruction to RV outflow)
When associated with a perimembranous VSD, how does double chambered RV develop?
Turbulent flow in ventricular outlet causes hypertrophy of endogenous trabecular tissue within the subinfundibular right ventricle
In double chambered RV, when the VSD shunts into the higher pressure portion of the RV, what is the physiology similar to?
ToF
Describe murmur/exam findings seen in double chambered RV?
- Subvalvular PS: Long, crescendo-decrescendo, over LUSB but lower than in isolated valvar stenosis
- No lock
- Palpable thrill common
True or False: Double chambered RV is a progressive condition with consequent RV hypertension and hypertrophy
True
How is double chambered RV managed?
Surgical resection and repair of associated defects
*Sometimes can be missed pre-operatively and found by persistent RV obstruction following VSD closure
How can a VSD result in aortic insufficiency?
Aortic valve leaflets prolapses to partially close VSD and gets distorted
Aortic arch obstruction is commonly associated with VSDs, especially if the VSD is caused by what?
Posterior malalignment of the outlet septum
Fixed splitting of S2 with diastolic rumble over tricuspid valve region?
Moderate-large ASD
Describe how NIRS monitoring works
- Similar to plethysmography of arterial pulse oximetry
- Infrared light emitted by diode within NIRS probe
- Sensor within probe measures amount of light absorbed the the area of interest
- Uses strong, nonpulsatile component to determine saturation in the tissue circulation
*Pulse ox uses weak pulsatile component to determine arterial saturation- often fails with poor tissue perfusion as pulsatile signal diminishes or disappears
What are some things that can make NIRS monitoring inaccuate?
- Poor perfusion (not as much impacts as in pulse ox)
- Motion artifact
- Ambient light noise like pulse ox
What are 2 common places to do NIRS monitoring?
Cerebral
Flank
What does the measurement of cerebral NIRS correspond to?
The level of oxyhemoglobin in the cerebral venous circulation
-Cerebral NIRS absorbs the majority of its light from the venous system based upon the wavelength used by the probe
With normal CO and oxygen delivery, cerebral NIRS should vary from the arterial oxygen saturation by what amount?
20-30%
A larger than normal difference between cerebral NIRS and arteria oxygen saturations can be indicative of what?
Oxygen delivery issues
NIRS can be used as a surrogate marker for what?
Mixed venous oxygen saturation
*Correlates well with SVC saturations in young infants
What is the most common cause of an elevated cerebral NIRS?
Hypercarbia
How does the pulmonary circulation respond to hypercarbia?
Vasoconstriction
How does the cerebral circulation respond to hypercarbia?
Vasodilation and increased blood flow
What happens to cerebral blood flow when the arterial CO2 level is decreased?
Cerebral blood flow decreases (can potentially acutely decrease intracranial pressure)
In post-op patients with cerebral NIRS monitoring, an elevation of NIRS without changes in other hemodynamic parameters should prompt investigation for what?
Hypercarbia
How does cerebral vasodilation and increased cerebral blood flow impact the NIRS?
Increased NIRS
-Increased cerebral blood flow results in elevated venous saturation
What may be helpful in children after Glenn to increase pulmonary blood flow?
Hypercarbia leading to cerebral vasodilation
What does hypocarbia do to pulmonary blood flow in Glenn patients?
Reduces it (by reducing cerebral blood flow)
What are 2 things that can cause an elevated NIRS?
- Hypercarbia
- Decreased O2 extraction in the brain due to significant brain injury (usually more subacute, but can happen acutely)
How does hypercarbia impact blood flow to the brain?
-Increases it by causing cerebral vasodilation
What is the classic carbonic anhydrase inhibitor?
Acetazolamide
How do carbonic anhydrase inhibitors work?
- Reversible inhibition of carbonic anhydrase in the proximal tubules of the kidneys
- Results in reduced hydrogen ion secretion and increased renal excretion of Na, K, Bicarb, and water
What do carbonic anhydrase inhibitors do to the serum bicarbonate level?
Lower it
What are carbonic anhydrase inhibitors used for?
- Metabolic alkalosis (lowers serum bicarbonate level, especially for ventilator weaning)
- Altitude sickness
What should be checked before giving acetazolamide?
pH
- Can have acidosis even in setting of alkalemia
- If serum pH <7.35-7.4, acetazolamide can worsen the acidosis
What can cause a primary metabolic alkalosis?
Chronic diuretic dependence
How do loop and thiazide diuretics cause a metabolic alkalosis?
Increase the renal excretion of Cl (negative anion)
How does the body compensate for metabolic alkalosis?
Respiratory acidosis- elevated PCO2
Why can a significant metabolic alkalosis be a barrier to weaning the ventilator?
It can suppress respiratory drive (body is trying to compensate with a respiratory acidosis by increasing PCO2)
What are options for treating metabolic alkalsis?
- Cl supplementation if Cl low
- Carbonic anhydrase inhibitor (increase bicarb secretion)
The initial dosing of acetazolamide should be over what time-frame?
24-72 hours (make sure that metabolic acidosis doesn’t develop with prolonged use)
When should acetazolamide be discontinued?
- pH <7.35
- Serum bicarbonate has decreased enough (to allow ventilator weaning, etc)
How do loop and thiazide diuretics impact a metabolic alkalosis?
Exacerbate it (by increased renal excretion of Cl)
What lab needs to be monitored in the setting of an ECG concerning for myopericarditis?
Troponin
What needs to be ruled out for adolescents with findings of myocardial ischemia?
Stimulant-induced coronary artery vasospasm
True or False: Exercise stress testing is contraindicated in the setting of acute myocarditis or pericarditis
True
What is the differential diagnosis for acute onset chest pain in an adolescent with elevated troponin levels?
- Myopericarditis
- Coronary artery abnormality (congenital or acquired like Kawasaki)
- Cardiomyopathy
- Drug toxicity
What testing may be needed to assess for a coronary artery abnormality in a teenager besides echo?
CTA or coronary aniography
True or False: Troponin is highly sensitive and specific for myocardial injury/necrosis and is superior to other cardiac enzymes like creatine kinase-MB or lactate dehydrogenase
True
What is the most common etiology for troponin elevation in adolescents who have acute chest pain and ECG changes?
Myopericarditis
What happens when you give someone with sinus tachycardia adenosine?
They may develop transient sinus slowing and AV block
What should you do for an infant with lethargy, tachycardia and decreased perfusion who has an ECG with normal sinus rhythm at a rate of 220?
Try a normal saline bolus, control any fevers, etc
True or False: Rates of sinus tachycardia in newborns frequently reach 220bpm and can go as high as 235bpm
True
What are typical AVRT rates for an infant?
250-300bpm range
*P-waves will be retrograde and hard to detect
What is the first line treatment for AVRT?
Adenosine
What should be done if adenosine doesn’t work in AVRT?
Try a higher dose (0.2mg/kg) and ensure good IV access and that it is given as a bolus followed by an IV flush
List forms of SVT seen in neonates/infants
AVRT
AVNRT
Flutter
EAT
How can adenosine be helpful in flutter?
It can block AV conduction long enough to see flutter waves
What is the management for a neonate in flutter?
Cardioversion
*Can use esmollol for rate control until further management possible
What is a clue to EAT?
P-wave axis is abnormal and not consistent with origin from the SA node
*Rates may vary
How can older patients (presentation after the neonatal period) present with tricuspid valve dysplasia?
- Abdominal pain and/or distension
- Peripheral edema
- Exertional dyspnea
- Palpitations (from new-onset arrhythmias)
What are physical exam findings consistent with tricuspid valve dysplasia?
- Murmur (valve regurgitation)
- Low-pitched rumble from severe stenosis or relative stenosis with severely regurgitant valve
- Hepatomegaly
- Peripheral edema (from increased CVP)
- JVD with a prominent V wave can sometimes be seen with severe TR and no interatrial shunt
- Possible cyanosis (if interatrial shunt, but usually subtle)
What is the surgical approach to tricuspid valve dysplasia?
Repair over replacement when feasible