Cardio Flashcards
What are two key cells and chemical mediators in the pathogenesis of atherosclerosis?
Macrphages and platelets (and damaged endothelial cells) release PDGF → smooth mm. cell proliferation
Platelets also release TGF-β → smooth muscle cell migration and ECM deposition
In which vein is oxygen tension the lowest?
Coronary sinus – myocardium has the highest extraction of any organ
Which maternal blood types are associated with a risk of hemolytic disease of the newborn/erythroblastosis fetalis?
O only:
- maternal blood types A or B when mismatched → IgM
- maternal blood type O → IgG against surface antigens
What is the triad of Wiskott-Aldrich syndrome?
WATER: Wiskott-Aldrich: Thrombocytopenic purpura, Eczema, Recurrent infections
From which aortic arch is the ductus arteriosus derived?
6th
What kind of tissue process predisposes people to aneurisms?
Myxomatous change in the media of large arteries, as part of cystic medial degeneration. Occurs in young pts Marfan syndrome or older pts with HTN.
What are fatty streaks? Who gets them?
intimal lipid-filled foam cells derived from macrophages and smooth muscle cells that have engulfed lipoprotein (predominately LDL) which enters intima through injured, leaky endothelium. They can be seen in all children >10 y.o. and as young as <1 y.o., and not all progress to atherosclerotic plaques.
What types of hemoglobin is elevated in β-thalassemia minor and β-thalassemia intermedia?
HbF, HbA2
Explain the molecular defects in B-thalassemia
mutations → defective transcription, processing, and translation of β-globin mRNA → deficiency in β-globin chains required for normal hemoglobin synthesis
What congenital heart abnormality is commonly seen in down syndrome?
endocardial cushion defects
What percentage of coronary blood flow comes from systole vs. diastole?
30% systole
70% diastole
Describe the murmur associated with a PDA
continuous flow murmur (systolic and diastolic)
Describe the murmur associated with a VSD
low pitched holosystolic murmur that gets louder with handgrip (↑ afterload)
How might the lungs appear in a drug user who recently died of complications of tricuspid endocarditis?
wedge-shaped infarcts from septic embolization
Describe the coronary steal phenomenon
- coronary ischemia → maximal dilatation of vessels in affected area
- administering heart specific arteriole dilators (adenosine, dipyridamole) → dilation of arterioles in unaffected areas → stealing from ischemic area including reduction of collateral flow to affected area
Which classes of antiarrhythmics prolong the QT interval?
Class 1A and Class 3
What would you see on echocardiogram in transposition of the great vessels?
aorta lies anterior and to the right of the pulmonary artery
How does digoxin slow down HR?
stimulates vagus nerve
What indicates the severity of mitral stenosis?
↓ interval b/w S2 and the opening snap indicates ↑ severity
Put the following in order of conduction velocity: atria, ventricles, purkinje fibers, AV node
Fastest → slowest: Purkinje Atrial muscle Ventricular muscle AV node
What is an important step in the management of a patient with endocarditis caused by S. bovis?
examination for colon cancer
What is milrinone?
A phosphodiesterase inhibitor
What is the mechanism of action of phosphodiesterase inhibitors?
↑ cAMP → → ↑ contractility and vasodilation
What amino acid is used in the synthesis of NO?
Arginine
When does an S4 heart sound occur?
Just before S1
What can cause an S4 heart sound?
atrial contraction against ventricular wall with ↓ compliance
- Age-related stiffening (not as loud)
- Restrictive cardiomyopathy
- LV hypertrophy due to prolonged HTN
What are the actions of ANP?
peripheral vasodilation and increased urinary secretion of sodium and water
What congenital heart disease is associated with differential cyanosis?
PDA
What drugs are used for prevention of thrombosis in angina pectoralis?
Asprin
Clopridogrel
What are the two major causes of valvular aortic stenosis?
- calcified bicuspid or normal valve (most common in US)
2. rheumatic fever (most common worldwide)
Where can mitral valve prolapse be heard best? What does it sound like?
cardiac apex - midsystolic click with late systolic murmur
What is the most sensitive provocative test for Prinzmetal angina?
Ergonovine test (stimulates both α-adrenergic and 5-HT receptors; both → vasoconstriction)
Describe the mechanism of NO smooth muscle relaxation
NO → guanylyl cyclase → GTP converted to cGMP → ↓ intracellular Ca2+ → ↓ MLCK activity → MLC dephosphorylation → smooth muscle relaxation
What conditions are associated with deletion of the long arm of chromosome 22?
facial (eg. cleft palate), cardiac (e.g. tetrology of fallot, interrupted aortic arch), or immunologic (e.g. T-cell deficiency, athymia); associated with DiGeorge syndrome
Which antiarrythmic is associated with a prolonged QT interval w/out increased risk for torsade de pointes?
amiodarone
Which two mechanisms lead to decreased Ca2+ intracellularly as the muscle begins to relax?
- Na+/Ca+ antiporter (3 Na in to cell / 2 Ca out of cell w/ no use of ATP)
- Ca2+ ATPase pumps Ca2+ into SR
How does dilated cardiomyopathy present?
symptoms of L and R ventricular CHF
What auscultation sound do you expect to hear in left ventricular systolic failure? How do you maximize the sound? What other heart condition could present this way?
S3 - accentuated by having patient lay in left lateral decubitus position; restrictive cardiomyopathy also presents this way
What maneuvers accentuate auscultation of mitral valve prolapse and hypertrophic myopathy? Why?
straining phase of valsalva, standing position, and amyl nitrate inhalation (causes vasodilation); the maneuvers decrease venous return to heart
What drug, when added to stable angina treatment regimen with β-blockers can have a severe additive negative chronotropic effect (→ bradycardia, hypotension, ↓ AV conduction, ↓ contractility)?
Non-dihydropyridine Ca2+ channel blockers (verapamil)
What is Brain Natriuretic Peptide (BNP)?
a substance released from the ventricles during CHF → diuresis and vasodilation (like ANP which comes from atria; both upregulate cGMP)
What are the 5 T’s of cyanotic congenital heart disease?
Tetrology of Fallot Tricuspid atresia Transposition of the great vessels Truncus arteriosus Total anomalous pulmonary venous return
A holosystolic murmur heard at the apex of the heart suggests:
mitral valve regurgitation
What is a functional mitral regurgitation?
Acute LV dilation → separation of mitral leaflets (note that in addition to holosystolic murmur this will often give an S3 due to increased atrial volume)
Where is aortic stenosis heard best?
aortic area in upper right chest
What is the technical name for mitral valve prolapse? What product builds up?
myxomatous mitral valve degeneration; dermatan sulfate accumulates in the connective tissue
Which auscultatory finding is the best indicator of severe mitral regurgitation?
presence of an audible S3 (indicates more blood has regurgitated during diastole → faster ejection into ventricle during systole)
Does the intensity of its systolic murmur correlate with the severity of mitral valve regurgitation?
No, often larger opening is quieter
Which kinds of beta receptors are present in vascular smooth muscle?
β2
What disease can cause fibrous intimal thickening with endocardial plaques limited to the right side?
Carcinoid syndrome. Tumor secretes high amounts of 5-HT - limited to the right heart because lungs have MAO.
What is the urinary product in carcinoid syndrome?
5-hydroxyindoleaacetic acid (5-HIAA; a serotonin metabolite)
Which holosystolic murmur is exaggerated by inspiration?
tricuspid regurgitation
What is nitroglycerine used for? What is the mechanism?
Rapid relief of stable angina symptoms; as a nitrate → venodilation → ↓ PREload
What heart condition causes an involuntary head bob? Why?
aortic regurgitation due to widened pulse pressure
What auscultatory finding often differs in patients with MVP caused by myxomatous degeneration vs. an MVP caused by papillary muscle dysfunction, ischemia, or dilated cardiomyopathy?
The midsystolic click is more often present with MVP caused by myxomatous degeneration
What causes Janeway lesions? Are they painful?
septic microembolization from bacterial endocarditis; painless
Are osler nodes painful?
yes
What histologic heart finding is classic in rheumatic fever patients?
interstitial myocardial granulomas called Aschoff bodies
Slender macrophages called caterpillar cells
Multinucleated Aschoff giant cells (also Mø)
What would chagas disease look like histologically in the heart?
intracellular trapanosomes w/ distension of individual mm. fibers
What would diphtheria myocarditis look like?
interstitial infiltrate of macrophages (without distinct Aschoff body granulomas in RF)
When you massage someone’s neck causing them ↓ BP, what are you stimulating? What nerve carries the afferent arc?
Carotid sinus baroreceptors → glossopharyngeal n. → solitary nucleus of medulla → vagus
Where is ACE produced?
pulmonary endothelium
Describe how HTN → LHF → RHF
LV concentric hypertrophy → ↓ LV diastolic compliance → ↑ filling P to maintain CO/SV → ↑ LA P → pulmonary venous congestion → ↑ hydrostatic P in lungs → capillary leak → pulmonary edema → alveolar collapse → ↓ ventilation → hypoxemia → reactive vasoconstriction/shunt → PAH → ↑ afterload → RHF
What is the most common site of deceleration-related injury in the aorta?
the isthmus, where the ascending and descending aorta meet
What is deposited by S. aureas that leads to heart valve vegetations?
fibrin and platelets
What arteries are most commonly affected by atherosclerosis in order of prevalence?
abdominal aorta > coronary arteries > popliteal arteries > internal carotids > circle of Willis
What does an AV shunt do to the pressure-volume curve in the heart?
- increases flow back to heart → EDV
2. reduces TPR → ↓ afterload
What artery supplies the diaphragmatic surface of the heart (inferior wall of L ventricle)?
PDA (which is supplied by RCA in 80-90% of people)
What drug is associated with atrialization of the RV (Ebstein’s anomaly)?
Lithium exposure in utero
What does constrictive pericarditis look like on CT?
bright thick wall around heart > 4mm
What antiarrhythmic drug exhibits the most use-dependence? What does this mean?
Class IC (e.g. flecainide, propafenone); QRS lengthens (i.e. effects of drug ↑) with ↑ HR
What antiarrhythmic drug exhibits reverse use-dependence? What does this mean?
Class III (e.g. dofetilide); the slower the HR, the more the QT interval is prolonged
How soon after initiation of total ischemia does it take for enough ATP to be lost so that myocytes stop contracting?
within 60 seconds
What is the most common cause of coronary sinus dilation?
↑ right-sided pressure due to pulmonary hypertension; note that the coronary sinus communicates freely with RA so anything that dilates the RA → coronary sinus dilation
How can the Fick principal be used to calculate CO?
CO = O2 consumption / arteriovenous O2 difference
What is a normal maximum pressure in the RV and pulmonary artery?
25 mmHg
What is a normal maximum pressure in the LV and aorta?
130 mmHg (systolic BP)
What is a normal maximum pressure in the atria?
around 10 mmHg
Is the minimum pressure in the pulmonary artery higher or lower than in the RV?
higher: RV minimum is about 4 and PA min is about 9
What does ANCA stand for? Which vasculitities have MPO-ANCA?
Anti-neutrophil chemoplasmic antibody;
Churg-strauss and Microscopic polyangiitis
