-
What are the blood supplies of the cardiac interventricular septum?
anterior septum: LAD
- posterior septum: (PD)
- 80%: RAD
- 20%: CFX
-
What supplies blood to the SA and AV nodes?
right anterior descending coronary
-
What non-cardiac symtpoms are associated with an enlarged left atrium?
- left atrium = most posterior
- left atrium enlargment = esophageal impingment
- dysphagia: obstruction
- hoarseness: impingement of laryngeal nerve (vagus)
-
What maintains cardiac output during exercise?
cardiac output = SV x HR
- early exercise: SV
- late exercise: HR
-
What is the mechanism of decreased cardiac output related to ventricular tachycardia?
- decreased preload/EDV
- if HR is too high, diastolic filling is incomplete
SV = EDV - ESV
-
What affects stroke volume?
- contractility
- preload (EDV)
- afterload (MAP, peripheral resistance)
-
What increases contractility?
- 1. catecholamines: increase SR calcium pump
- 2. increased intracellular calcium
- 3. digitalis: decreased ATPase pump, increased intracellular sodium (causes increased Ca2+)
- 4. decreased extracellular sodium: decrease Na+/Ca2+ exchanger
-
What decreases contractility?
- 1. decreased B1 signaling: decreased cAMP
- 2. heart failure
- 3. acidosis
- 4. hypoxia/hypercapnea
- 5. non-dihydropyridine CCB
-
What increases myocardial O2 demand and promotes vulnerability to ischemic damage?
- 1. increased afterload
- 2. increased heart rate
- 3. increased heart size
- 4. increased contractility
-
What increases preload?
- 1. exercise
- 2. overtransfusion: increased blood volume
- 3. excitement: sympathetic stimulation
-
What is an example of a venodilator and what is its main effect?
- Nitroglycerin
- venodilates: decreases preload
-
What is an example of a vasodilator and what is its main effect?
- Hydralazine
- vasodilator: decreases afterload
-
What is the ejection fraction of the heart?
- measure of contractility
- normal: >55%
- EF = SV/EDV = (EDV - ESV)/EDV
-
Which conditions generally increase blood viscosity? What cardiovascular effect does this have?
- increase blood viscosity:
- polycythemia vera
- hyperproteinemic states (e.g. multiple myeloma)
- hereditary spherocytosis
cardiovascular effect: increased viscosity increases resistence on vessels
-
What vessel type accounts for most of the total peripheral resitance?
arterioles
resistance vessels that regulate capillary blood flow
-
What decreases total peripheral resistance? What CV effect does this have?
- vasodilators
- exercise
- AV shunt
- CV effect:
- increased venous return
- increased CO
-
What increases total peripheral resistance? What CV effect does this have?
hemorrhage
- CV effect:
- decreased venous return
- decreased CO
-
What decreases cardiac inotropy? What CV effect does this have?
- heart failure
- narcotic overdose
CV effect: decreased CO
-
What is the operating point of the heart?
- = when CO is equal to venous return
- = intersect of cardiac/vascular function curves
-
What does the X-intercept on a cardiac/vascular function curve signify?
- = mean systemic pressure
- = venous return at 0
-
Which murmurs increase in intensity with inspiration?
right sided heart murmurs
inspiration = increased pulmonary artery flow/volume, decreased left atrium return
-
Which murmurs increase in intensity with expiration? Why?
left sided heart murmurs
exhilation = increased left atrium return
-
Which murmurs increase in intensity with hand grip maneuver? Why?
- increased murmurs:
- mitral regurgitation
- VSD
hand grip maneuver: increases systemic vascular resistance
-
Which murmurs increase in intensity with the Valsalva maneuver? Why?
- (most murmurs decrease)
- increased murmurs:
- mitral valve prolapse
- hypertrophic cardiomyopathy
Valsalva: decreases venous return
-
Which murmurs decrease in intensity with rapid squatting? Why?
- decreased murmurs:
- hypertrophic cardiomyopathy
- mitral valve prolapse
- rapid squatting:
- increases venous return
- increases afterload
-
How is a hypertrophic cardiomyopathy murmur best heard?
- systolic murmur
- left sternal border
- increases: Valsalva (decreased venous return)
- decreases: rapid squatting
-
What is "pulsus parvus et tardus"?
= palpable pulse is lower than indicated by heart sounds
- can lead to syncope
- often a sign of aortic stenosis (age-related, bicuspid)
-
What type of heart condition is indicated by a wide pulse pressure? What murmur would you expect? Other symptoms?
aortic stenosis
- murmur:
- diastolic at aortic area (upper right sternal border)
- high-pitched, "blowing"
- increased by exhilation (left-sided)
- decreased by vasodilators (decreased afterload)
- other symptoms:
- head bobbing
- bounding pulses
-
What maneuvers increase the intensity of mitral valve prolapse?
- decreased venous return:
- Valsalva
- venodilators
-
What maneuvers increase the intensity of mitral stenosis?
- increase in left atrium filling:
- exhilation
-
What would you suspect in a neonate with a continuous machine-like murmur? When would the murmur be loudest?
- suspect:
- congenital rubella
- prematurity
-
When does the most rapid ventricular filling occur?
just after mitral valve opens
-
When does the slowest ventricular filling occur?
just before mitral valve closes
-
During which phase of the cardiac cycle does the most O2 get consumed?
isovolumetric contraction
-
What makes cardiac muscle contraction different from skeletal muscle contraction?
- 1. AP plateau: Ca2+ influx
- 2. gap junctions: electrical coupling
- 3. automaticity: If channels cause spontaneously depolarization in nodal cells during diastole
-
What respectively increases and decreases SA node conduction velocity (i.e. depolarization)?
- SA node conduction velocity = heart rate
- slope of phase 4 of pacemaker AP = heart rate
- increased:
- catecholamines (adrenergic)
- decreased:
- Ach (PNS: muscarin)
- adenosine (vasodilator?)
-
What does a T-wave inversion indicate?
recent MI
-
What causes a U wave? Where is it on an EKG?
U wave: hypokalemia, bradycardia
- EKG: after T wave and before P wave
- (i.e. between ventricular repolarization and atrial depolarization)
-
What are common features of people born with congenital prolonged QT syndromes?
- dysfunctional cardiac potassium and/or sodium channels
- predisposed to torsades de pointes (VT, Vfib)
- associations:
- severe congenital sensorineural deafness (Jervell/Lange-Nielsen syndrome)
-
What is torsades de pointes and its causes?
- torsades de pointes = ventricular tachycardia characterized by shifting sinusoidal waveforms on ECG
- predisposes to ventricular fibrillation
- causes: anything that prolongs QT
- congenital prolonged QT syndrome
- Type III antiarrythmics (e.g. amiodarone)
-
What drugs are useful in treating atrial fibrillation?
-
What drugs are useful in treating atrial flutter?
- antiarrythmics:
- Type IA
- Type IC
- Type III
definitive treatment: convert to sinus rhythm
-
What infectious disease may result in 3rd degree heart block? What would you expect on ECG? How would you treat the heart condition?
Lyme Disease: Borrelia burgdorferi (tick)
- 3rd degree heart block:
- independent beating of atria and ventricles
- no relation between P waves and QRS complexes
- atrial contraction faster than ventricular contraction
treatment: pacemaker
-
What are the ECG features of V-fib and how would you treat it?
- ECG:
- completely erratic rhthym
- no identifiable waves
- can be fatal
-
What are the main features of ANP?
ANP = atrial natriuretic peptide = diuretic from atria
- ANP increased by:
- increased blood volume
- increased atrial pressure
- effects:
- dilates afferent arteriole/constricts efferent arteriole via cGMP
- causes diuresis
- "escape from aldosterone"
-
What is the "Cushing Triad" and what causes it?
- Cushing Triad:
- hypertension
- bradycardia
- respiratory depression
- cause: central chemoreceptor response (pH, PCO2)
- increased intracranial pressure: constricts arterioles: cerebral ischemia: SNS response: hypertension: reflex bradycardia
-
What are the differences between the peripheral and central chemoreceptors?
- peripheral:
- detect PO2, some PCO2, and pH
- arteriolar blood content
- central:
- detect PCO2 and some pH
- brain interstitial fluid
-
What are the basic ECG features of atrial fibrillation?
- 1. no P waves
- 2. irregularly irregular baseline
- 3. irregularly spaced QRS complexes
-
What are the basic ECG features of atrial flutter?
- 1. "sawtooth" flutter waves
- 2. back-to-back P waves
-
What are the basic ECG features of 2nd degree heart block Type I?
- 1. progressively prolonged PR intervals result in a "dropped" P wave
- 2. usually asymptomatic
-
What are the basic ECG features of 2nd degree heart block Type II?
- 1. "dropped" P wave without any progressive lengthening of PR interval
- 2. usually a 2:1 distribution (2 P waves: 1 QRS complex)
- 3. can lead to 3rd degree heart block
-
What are the basic ECG features of ventricular fibrillation? How is it treated?
- ECG:
- 1. completely erratic rhythm
- 2. no identifiable waves of any kind
- 3. can be fatal
-
How is the O2 demand of the heart maintained?
coronary blood flow
(can't increase extraction rate because already 100%)
-
What factors determine blood flow autoregulation in the heart?
-
What factors determine blood flow autoregulation in the brain?
-
What factors determine blood flow autoregulation in the skeletal muscle?
-
How are the CV responses to hypoxia different in the lung versus other tissues?
lung hypoxia: causes vasoconstriction to shunt blood for ventilation/perfusion match
hypoxia in other tissues: causes vasodilation
-
What are common mechanisms of edema and their causes?
- 1. increased capillary pressure: heart failure
- 2. decreased plasma proteins: nepthrotic syndrome, liver failrue
- 3. increased capillary permeability: toxins, infections, burns
- 4. increased interstitial fluid colloid osmotic pressure: lymphatic blockage
-
What are common causes of early cyanosis?
- right-to-left shunts:
- tetralogy of fallot
- TGA
- truncus arteriosus persistance
- Tricuspid atresia
- Total anamolous pulmonary venous return (TAPVR)
squatting helps
-
What are the features of Tetralogy of Fallot? Which is most important for prognosis?
- 1. pulmonary valve stenosis (most important for prognosis)
- 2. RVH
- 3. VSD
- 4. overriding aorta
cause: anterosuperior displacement of infundibular septum
- s/s:
- early cyanosis (blue baby)
- cyanotic "spells"
- squatting helps cyanosis (increased TPR)
- X-ray: boot-shaped heart
-
What features are required to sustain life in a baby with TGA?
- right-to-left shunt required for blood mixing:
- PDA
- VSD
- patent foramen ovale
most infants die without immediate surgical correction
-
What valvular disruption is common with coarctation of the aorta?
aortic regurgitation
-
What is a potential cause of differential cyanosis (i.e. lower extremity cyanosis)?
uncorrected PDA
-
Why is a PDA normal in fetal life but not neonate life?
- fetal: PDA allows right-to-left shunt which is normal
- neonate: PDA switches to left-to-right shunt which is abnormal
-
What congenital abnormalities are associated with 22q11 syndromes?
- Truncus arteriosus
- Tetralogy of Fallot
-
What congenital abnormalities are associated with Down's syndromes?
- endocardial cushion defects (AV septal defect)
- ASD
- VSD
-
What congenital abnormalities are associated with congenital rubella?
- PDA
- pulmonary artery stenosis
- septal defects
-
What congenital abnormalities are associated with Turner syndromes?
(preductal) coarctation of aorta
-
What congenital abnormalities are associated with Marfan's syndromes?
aortic insufficiency (late)
-
What congenital abnormalities are associated with diabetic mothers?
transposition of great arteries
-
Which skin cell is involved with xanthomas?
lipid-laden histiocytes in skin
-
What are the most sites for atherosclerosis?
abdominal aorta > coronary artery > popliteal artery > carotid artery (> Circle of Willis?)
-
What cytokines are involved in atherosclerosis formation?
-
What is the progression of atherosclerosis development?
- 1. endothelial dysfuction
- 2. macrophage and LDL accumulation
- 3. foam cell formation
- 4. fatty streaks
- 5. smooth muscle cell migration (TGF-b, PDGF)
- 6. fibrous plaque
- 7. complex atheromas
-
What are the different associations between thoracic and abdominal aortic aneurysms?
- thoracic aneurysm association:
- hypertension
- cystic medial necrosis (Marfan's)
- abdominal aneurysm association:
- atherosclerosis
- men
- smoking
- age
-
What are the key features of aortic dissection?
longitudinal intraluminal tear: false lumen
- s/s: tearing chest pain radiating to back
- CXR: mediastinal widening
- CT: false lumen within aorta
-
What is coronary steal syndrome?
= when a vasodilator aggravaes ischemia by shunting blood from an area of critical stenosis to an area of higher perfusion
-
What is the most common cause of myocardial infarction?
acute thrombosis: coronary artery atherosclerosis
-
What is the most common case of sudden cardiac death?
- (death within 1 hour of symptoms)
- lethal arrythmia: V-Fib
-
What are the most likely occluded coronary arteries?
LAD > RCA > CFX
-
What are common ECG changes for subendocardial infarct vs transmural infarct MI?
- subendocardial infarct:
- ST depression
- transmural infartct:
- pathologic Q waves
- ST elevation
-
What are common causes of dilated cardiomyopathy?
ABCCCD
- alcohol abuse
- beri beri
- cocaine abuse
- Chagas' disease
- Coxsackie B virus myocarditis
- Doxorubicin toxicity
-
Which cardiomyopathies reflect diastolic dysfunction?
-
Which drugs improve mortality with CHF?
- ACE inhibitors
- Beta-blockers
- spironolactone
- angiotensin receptor antagonists
-
What type of hypersensitivity reaction is rheumatic fever?
Type II hypersensitivity: antibodies to M protein
-
Which conditions are associated with fibrinous pericarditis?
- MI
- Dressler's syndrome
- uremia
- radiation
-
Which conditions are associated with serous pericarditis?
- noninfectious inflammatory diseases:
- SLE
- rheumatic fever
-
What is pulsus paradoxus? What conditions is it associated with?
= when systolic BP drops >10 mmHg during inspiration
- conditions:
- severe cardiac tamponade
- asthma
- obstructive sleep apnea
- pericarditis
- croup
-
What are the features of cardiac tamponade?
= compression of heart by fluid within pericardium
- s/s:
- hypotension
- increased HR
- pulsus paradoxus
- increased JVP
- distant heart sounds
- equalization of diastolic pressure in all chambers
-
What are the associations of rhabdomyomas?
- most common primary cardiac tumor of children
- associated with tuberous sclerosis
-
What are the associations of myxomas?
- most common primary cardiac tumor in adults
- 90% in atria (esp. left)
- "ball-valve" appearance on CT
- multiple syncopal episodes
- Kussmaul's sign: increased JVP with inspiration
-
What are common original tumors that metastasize to the heart?
-
What are examples of large-vessel vasculitis and their general age of presentation?
- temporal/giant cell arteritis (elderly women)
- Takayasu's arteritis (Asian women <40yo)
-
What are examples of medium-vessel vasculitis and their general age of presentation?
- polyarteritis nodosum (young adults)
- Kawasaki's disease (Asian <4yo)
- Buerger's disease (heavy smokers, males <40yo)
-
What are examples of small-vessel vasculitis and their associated antibody?
- microscopic polyangiitis (p-ANCA)
- Wegener granulomatosis (c-ANCA)
- Churg-Strauss syndrome (p-ANCA)
- Henoch-Schonlein purpura (IgA)
- Sturge-Weber disease
-
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