Cardio - FA Phys/Patho p290 - 304 Flashcards
Explain briefly what happens in each phase during myocardial action potential ?
Phase 0 - opening of voltage gated Na channels open, rapid upstroke and depol
Phase 1 - inactivation of voltage gated Na channels, voltage gated K+ channels begin to open
Phase 2 - plateau, Ca2+ influx, K+ efflux,
Phase 3 - repol by K+ efflux
Phase 4 - resting potential by high K+ perm
How is cardiac muscle action potential compare to skeletal muscle action potential?
Cardiac muscle action potential has a plateau, which is due to Ca2+ influx and K+ efflux.
Cardiac muscle contraction requires Ca2+ influx from ECF to induce Ca2+ release from sarcoplasmic reticulum (Ca2+-induced Ca2+ release).
Cardiac myocytes are electrically coupled to each other by gap junctions
Which phases of AP are not present in SA/AV node action potential?
There’s no phase 1 or 2
Which channel is responsible for phase 0 of SA node AP? What is phase 0?
opening of voltage gated Ca channels; upstroke
What are Na channels’ role in phase 0 of SA node?
None, Fast voltage gated channels are permanently inactivated here bc of the resting voltage of these cells is closer to zero than in ventricular myocytes
What part of the AP determines HR?
The slope of phase 4 in the SA node determines HR.
How does SNS activation increase HR?
Sympathetic stimulation inc the chance that If channels are open and thus inc HR.
Normal duration of PR interval?
<200 msec
List the following in order of speed of conduction: atria, ventricles, AV, bundle of his, purkinje fibers
Purkinje > atria > ventricles >Bundle of His> AV node
Normal duration of QRS?
<120 msec
U wave caused by?
hypokalemia, bradycardia
Which drugs cause long QT?
AntiArrythmics (Class Ia, III) Antibiotics (Macrolides - and not an antibiotic but also the HIV anti viral rx Protease inhbitors and anti- malaria Chloroquine) Anti”C”ychotics (haloperidol, Risperidone)\ AntiDepressants - TCAs Anti-Emetics - Odansetron
Other than drugs, what else can cause long QT?
dec K+, dec Mg2+, dec Ca2+, congenital abnormalities.
Long QT leads to? How to treat it?
Torsades de pointes; Tx = MgSO4
Which congenital long QT is more common?
Jervell and Lange-Nielsen (AR)
Which congenital long QT syndrome is associated with deafness?
Jervell and Lange-Nielsen
ECG pattern of Brugada syndrome?
ECG pattern of RBBB (wide QRS, slurred S, T irreg) + ST elevation esp in V1-V3
Brugada syndrome lead to a an inc risk of?
Vtach and SCD
What is underlying patho mech of WPW syndrome?
Abnormally fast conduction from atria –> ventricle, bypassing the AV node
ECG signs of WPW?
delta wave + wide QRS + short PR
ECG signs of 1st degree AV block?
prolonged PR (>200msec)
ECG signs of 2nd degree AV block, Mobitz I?
progressive lengthening of PR interval until a beat is dropped
ECG signs of 2nd degree AV block, Mobitz II?
Dropped beats not preceeded by progressively longer PR internals - can be 2 or more P waves to one QRS
How does one know that 2nd degree AV block has progressed to 3rd degree?
When atria and ventricle beat independent of one another - P waves and QRS not associated with each other.
How to treat 1st/ 2nd/ 3rd degree AV block?
1st - no Tx
2nd type II - pacemaker
3rd - pacemaker
Which infectious disease is associated with 3rd degree AV block?
Lyme Disease
Recombinant form of B type natriuretic peptide?
Nesiritide
Physiological effect of ANP?
Causes vasodilation and dec Na resorption at renal collecting tubule, VD of aff art and VC of eff art
ANP uses which 2nd messenger?
cGMP
What causes the release of ANP vs BNP
ANP - rel from atrial myocytes in response to inc blood vol and atrial pressure
BNP - rel from ventric myocytes in response to inc tension
Physiological effect of ANP?
Causes vasodilation and dec Na resorption at renal collecting tubule, VD of aff art and VC of eff art
Which nerves are afferent to the solitary nucleus from the carotid and aortic body?
Cn IX, X
Which CV disease associated with DeGeorge?
Persistent Truncus Arteriosus, Tetrology of Fallot
Due to failure of aorticopulmary septum formation?
Persistent Truncus Arteriosus
Due to failure of aorticopulmary septum to spiral?
Transposition of Great Vessels
What bedside maneuver would improve cyanosis in Tetrology of Fallot? why?
Squatting - inc systemic vasc resistence, dec R–> L shunt
Which congenital CV disease assoc with maternal mood disorder?
Ebstein anomaly - can be caused by Li exposure in utero if mother is bipolar
Cushing Reflex triad
hypertension, bradycardia, respiratory depression
Types of chemoreceptors and stimulators for them
Peripheral: lower Po2, lower pH, high PCo2 Central: changes in pH and PCo2 (brain interstitial fluid)
What does PWCP measure (approximate)?
Left atrial pressure (<12mmHg)
Hypoxia’s effect on the Lung’s vessels
VC
Metabolites that influence skeletal muscle during exercise
Adenosine, CO2, lactate, K, H
Frequency of L-R shunt CV disease from most common to least?
VSD>ASD>PDA
Which L-> R shunt assoc with Cri du Chat?
VSD
Female patient with broad chest and widely spaced nipples and streak ovaries would likely have which Congenital CV disease
Preductal Coarctation of Aorta or Bicuspid Aortic valve - this woman has Turners
Late cyanosis in lower extremities
PDA
Assoc with notching of ribs
post ductal Coarctation of Aorta
Assoc with clubbing of fingers and polycythemia?
Eisenmenger Syndrome
In persistent truncus arteriosus, most patients have accompanying
VSD
D-transposition of great vessels is due to what? What is the life expectancy of infants
failure of aorticopulmonary septum to spiral. Most infants die within the first few months of life.
Tricuspid atresia is
Absence of tricuspid valve and hypoplastic RV
What is the Tetralogy of Fallot
1 Pulmonary infundibular stenosis 2 RVH 3 Overriding aorta 4 VSD
TAPVR Total anomalous pulmonary venous return is associated with
ASD and sometimes PDA to allow for right->left shunting to maintain cardiac output.
Ebstein anomaly is seen if the mother has bipolar disease and ingested
Lithium exposure in utero
A pt with a microdeletion of chromosome 7 would likely have what disease?
Supravalvular aortic stenosis, pt has Williams
Mother has fever, infection, swollen lymph nodes and rash that travels down the body during pregnancy - child is at risk for?
Mother has rubella - PDA, Pulm a stenosis, septal defects
Tall man with abnormally long arms are prone to which heart disorders?
MVP, Aortic regurgitation, thoracic aortic aneurysm
What is a hypertensive urgency? What BP?
severe inc in BP - ≥ 180/ ≥120 mmHg
Define HTN?
Persistent systolic BP ≥ 130mmHg and/ord diastolic BP ≥ 80 mmHg
The renal a in fibromuscular dysplasia has what kind of appearence?
“string of beads” appearence
What type of HTN can cause microangiopathic hemolytic anemia?
HTN emergency
What happens to renal a in HTN that shows up on PAS stain?
renal artery hyalinosis
VSD is seen in which 2 syndromes?
Fetal alcohol syndrome, Down’s syndrome
Partial deletion of chr 7 will lead to what CV issue?
Supravalvular aortic stenosis.
What thymus disorder is seen with truncus arteriosus, and tetrology of fallot? What chromosome?
DeGeorge syndrome - thymic aplasia; 22q11
what type of arterioslerosis is seen in med sized arteries?
Monckeberg
what are xanthomas?
plaques or nodules composed of lipid laden histiocytes in skin
hypercholesterolemia can manifest what eye pathology earlier than the general population?
Corneal arcus?
Pipestem appearence of an a. on an CXR is a sign of what?
Monckeberg - medial calcific sclerosis
onion skinning of an artery is a proliferation of what cell type/which arteries?
smooth musc cells of small arteries and arterioles
Essential hypertension or DB lead to what pathology of arteries?
small arteries and arterioles - hyaline arteriolosclerosis
Why is there no obstruction of blood flow with Monckeberg arteriolosclerosis?
Affects tunica media, not intima, so lumen diam not affected
Most common locations of atherosclerosis in order?
Ab aorta > Coronaries > Popliteal a > carotid a
Syphilis associated with what type of cardiac pathology? Which stage of syphilis?
Thoracic aortic aneurysm, tertiary syphilis
Which sexual genetic disorder could potentially lead to thoracic aortic aneurysm?
Turner’s (45, XO) bc of association with bicuspid aortic aneurysm
Cystic medial degeneration associated with which cardiac pathology?
Thoracic aortic aneurysm
Tobacco, cocaine, and triptans are associated with triggering which cardiac pathology?
Prinzmetal angina
Mediastinal widening on CXR is a sign of ? (as a consequence of syphillis)
aortic dissection
What is Coronary steal syndrome?
Giving vasodilators in a patient with coronary stenosis will cause the dilation of normal vessels and reduces the flow to area distal to the stenosis. This is the principal behind cardiac stress test.
ECG signs of transmural vs subdendocardial MI?
transmural - ST elevation (STEMI), Q waves subendocardial - NSTEMI = ST depressions
Diseases associated with sudden cardiac death
CAD, cardiomyopathy, heriditary ion channelopathies (long QT syndrome, Brugada syndrome)
wavy fibers appear how soon after an MI?
4-24 hrs
Biggest complication 1-3d post MI?
Postinfarction fibrinous pericarditis
If one sees macrophages and mariginal granulation tissue, how many days post MI?
3-14d
Major complications 3-14 days post MI?
free wall rupture –> tamponade papillary muscle rupture –> mitral regurge, IV septum rupture LV pseudoaneurysm
What changes are seen in heart tissue in the first 4 hours post MI?
none
First cardiac biomarker to rise post MI?
myoglobin
Most specific cardiac biomarker post MI?
Cardiac troponin I
Which cardiac biomarker is useful to determine if there was a re-infaction?
CK-MB, normally falls after 48hrs, so if high after that, sign of re-infarction
Most common cause of death post MI?
Arrythmia
V1 - V2 leads MI = which area of heart? artery?
anterior, over the septum - LAD
V3- V4 leads MI = which area of heart? artery?
anterior side to the apex - distal LAD
V5 - V6 leads MI = which area of heart? artery?
anterior side to lateral heart - LAD or L circumflex
Leads I, aVL = which area of heart? artery?
lateral side - L circumflex
Leads II, III, avF = area of heart? artery?
inferior heart - R circumflex
What is Dressler syndrome?
Autoimmune, leads to fibrinous pericarditis
When would a postinfarction fibrinous pericarditis occur post MI?
1-3 d post MI
Which two complications of an MI can occur up to 14 days post MI?
Ventric free wall rupture, ventricular pseudoaneurysm formation (contained free wall rupture)
Which complication can appear 2 weeks to months post MI?
True ventricular aneurysm
When is the greatest risk for septal rupture post MI?
3-14 days post MI
