Cardiology Flashcards
Hypoperfusion of end organs stimulates the heart to…
Maximize contractility and heart rate in an attempt to increase cardiac output
Hypoperfusion signals the kidneys to…
Retain salt and water through renin-angiotensin system
__________ released by the sympathetic nervous system to increase heart rate and myocardial contractility during hypoperfusion
Catecholalmines
What are some congenital lesions that cause increased pulmonary blood flow?
- Large VSD
- Large PDA
- Transposition of the great arteries
- Truncus arteriosus
- Total anomalous pulmonary venous connection (TAPVC)
What obstructive lesions may cause CHF?
- Severe aortic, pulmonary, and mitral valve stenosis
- Coarctation of the aorta
- Interrupted aortic arch
- Hypoplastic left heart syndrome
What acquired heart diseases may lead to CHF?
- Viral myocarditis (common)
- Endocarditis, pericarditis
- Metabolic disease (hyperthyroidism),
- Medications
- Cardiomyopathies
- Ischemic diseases
- Dysrhythmias
What are clinical features suggesting pulmonary congestion in CHF?
- Tachypnea, cough, wheezing, and rales on examination
- Pulmonary edema on CXR
What clinical features are evidence of impaired myocardial performance in CHF?
- Tachycardia, sweating, pale or ashen skin color
- Diminished urine output
- Enlarged cardiac silhouette on CXR
What clinical features are evidence of systemic venous congestion in CHF?
Hepatomegaly and peripheral edema
What are late manifestations of CHF?
Cyanosis and shock
What types of medical management are used to treat CHF?
- Cardiac glycosides (digoxin)
- Loop diuretics (furosemide)
- Inotropic medications administered IV (dobutamine, dopamine)
What other methods of management are used to treat CHF besides medication?
- Interventional catheterization (balloon valvuloplasty for critical aortic and pulmonary valve stenosis)
- Surgical repair (definitive treatment of CHF secondary to congenital heart disease)
Approximately ___% of children have an innocent heart murmur at some point during childhood
50%
What are the acyanotic congenital heart diseases?
ASD, VSD, PDA, Coarctation of the aorta, Aortic stenosis, Pulmonary stenosis
What are the differences between Ostium primum ASD and Ostium Secundum ASD?
- Ostium Primum: Defect in lower portion of atrial setptum, common in Down Syndrome
- Ostium Secundum: Defect in middle portion of atrial septum, most common type of ASD
What is a sinus venosus ASD?
A defect high in the septum near the junction of right atrium and SVC - the right pulmonary veins usually drain anomalously into the right atrium or SVC instead of the left atrium
How does an ASD lead to increased pulmonary blood flow?
Blood flows from the left atrium to the right (higher resistance to lower resistance) leading to increase in size of the right atrium and right ventricle, and to increased pulmonary blood flow
What are 3 innocent heart murmurs?
- Still’s murmur (ages 2-7)
- Pulmonic systolic murmur (any age)
- Venous Hum (any age, but especially school age)
Describe a still’s murmur
- Grade 1-3, systolic vibratory twanging or buzzing.
- Loudest supine and louder with exercise
- Mid-left sternal border
Describe a pulmonic systolic murmur
- Grade 1-2, peaks early in systole
- Blowing, high pitched
- Upper left sternal border
Describe venous hum
- Continuous murmur heard only sitting or standing - disappears if supine
- Neck and below the clavicles
Patients with a ostium primum defect may develop ______ _______ that results in CHF
mitral regurgitation
Physical examination findings of ASD include:
- Increased right ventricular impulse
- Systolic ejection murmur best heard at mid and upper left sternal borders
- Fixed split second heart sound
What is the management of ASD?
Treatment is closure by open heart surgery to prevent right sided heart failure, pulmonary hypertension, dysrhythmias and paradoxic embolism
What are the classifications of VSD?
- Inlet
- Trabecular (muscular)
- Membranous
- Outlet (supracristal)
How does a VSD lead to pulmonary hypertension?
Blood flows from left to right ventricle owing to lower resistance within pulmonary circulation; with time, the pulmonary vessels hypertrophy in response to increased pulmonary flow leading to increased vascular resistance
What two factors determine the amount of blood flow directed from one side of the heart to the other in a VSD?
Determined by the size of the VSD and the degree of pulmonary vascular resistance (PVR)
As the size of the VSD decreases, the intensity of the murmur _______
Increases (thrill and grade 4 high pitched holosystolic murmur may indicate small VSD)
If excessive blood flows across the VSD (moderate or large VSDs) then a diastolic murmur of _____ _______ may be heard at the apex
mitral turbulence (mitral filling rumble representing excess blood from the lungs no passing through the mitral valve)
What is Eisenmenger syndrome?
If PVR remains elevated, pulmonary hypertension becomes irreversible, even if VSD is surgically closed - PVR exceeds SVR and shunting changes from left-to-right to right-to-left
When is surgical closure indicated in management of a VSD?
- Heart failure refractory to medical management
- Large VSDs with pulmonary hypertension (closed at 3-6 months)
- Small to moderate VSDs are closed between 2-6 years of age
What is the medical management of VSDs?
Medical management of CHF is indicated in a symptomatic child (Cardiac glycosides, Loop diuretics, Inotropic medications administered IV)
What is connected by the ductus arteriosus in the fetus?
Connects the pulmonary artery to the aorta
Incidence of PDA is high in _____ infants
preterm
Physical examination findings of PDA?
- “Machinery-like” continuous murmur at upper left sternal border
- If the left-to-right shunt is large: diastolic rumble of blood flow across mitral valve at the apex
- Widened pulse pressure and brisk pulses
Risk of ______ _______ is significant in children older than several years of age with a PDA
Pulmonary hypertension
_____ is used in premature infants to close a PDA medically
Indomethacin
PDAs may be closed surgically by what methods?
- Coil embolization
- Video-assisted thoracoscopic surgery
- Ligation in a thoracotomy
What is Coarctation of the Aorta?
Narrowing of the aortic arch just below the origin of the left subclavian artery and typically at, or just proximal to the ductus arteriosus
Neonates or infants with severe coarctation may depend on a right-to-left shunt through the ____ for perfusion of the lower thoracic and descending aorta
PDA
What is the key blood pressure finding in coarctation of the aorta?
Blood pressures may be elevated in the upper extremities and low in the lower extremities (before the onset of CHF)
What occurs once an infant with Coarctation of the Aorta develops CHF?
- Pulses in all four extremities are poor
- Any murmur is absent
- Hypotension may develop
What findings are significant for the following in older children or adolescents with coarctation of the aorta?
- Femoral pulse:
- Aortic valve:
- Turbulence:
- Collateral vessels:
- Femoral pulse: is dampened and delayed until after the radial pulse
- Aortic valve: Bicuspid aortic valve or aortic stenosis is present in 50% of patients
- Turbulence: bruit through the coarctation may be audible at the left upper back
- Collateral vessels: Intercostal arteries may develop into collateral vessels which allow the ascending aortic circulation to circumvent the coarctation
Initial management of coarctation of the aorta (2)?
- Intravenous prostaglandin E (PGE) to open the ductus arteriosus
- Inotropic medications are given to overcome myocardial depression
What corrective repairs are used to treat coarctation of the aorta (2)?
- Surgery - excision of the narrowed segment followed by end-to-end anastomosis
- Balloon angioplast is the therapy of choice for recurrent coarctation
What is pathologic aortic stenosis?
Commissural fusion of the three normal leaflets leading to a bicuspid or unicuspid valve
How does aortic stenosis lead to myocardial ischemia?
- Aortic stenosis results in reduced left ventricular output
- Imbalance between myocardial oxygen demand (which is higher than usual due to increased ventricular work as a result of outflow obstruction) and supply
Severe aortic stenosis may be associated with ______ of the left ventricle
hypoplasia (as a result of imparied fetal left ventricular development)
Neonates with severe stenosis appear normal at birth but develop signs and symptoms of CHF at ____ -____ hours of age
12-24 hours of age
Older children who develop severe stenosis show what symptoms?
- Exercise intolerance
- Chest pain
- Syncope
- Sudden death
What are indications for intervention of aortic stenosis?
- CHF
- Chest pain or syncope
- Documentation of high resting pressure gradient across the aortic valve (>50-70 mm Hg)
Management of aortic stenosis?
- Balloon valvuloplast (inital management)
- Surgery for aortic stenosis with insufficiency and 5-10 years after palliative valvuloplasy