cardiology Flashcards
what is the most posterior part of the heart?
LA
what is the most anterior part of the heart?
RV
where does the pericardial cavity lie?
in between the layers of serous pericardium (visceral and parietal)
name layers of pericardium from outer to inner
fibrous
parietal (serous)
visceral (serous)
what parts of the heart does the LAD and its branches supply?
ant 2/3 of IV septum
anterolateral papillary muscle
anterior surface of LV
what is the most commonly occluded artery?
LAD
what parts of the heart does the PDA supply?
AV node (depending on dominance)
post 1/3 of IV septum
post 2/3 walls of ventricles
posteromedial papillary muscle
what artery supplies blood to the RV?
right (acute) marginal artery
what parts of the heart does teh RCA supply?
SA node
infarct of what artery may cause nodal dysfunction s/a bradycardia or heart block?
RCA
describe where the PDA arises from based on dominance and which is most common
right dominance (85%) - PDA arises from RCA
left dominance (8%) - PDA arises from LCX
codominant (7%) arieses from both
when does coronary blood flow peak (what part of heart cycle)
early diastole
stroke volume is affected by what parameters?
SV CAP
SV is affected by Contractility, Afterload, and Preload
inc contractility (anxiety, exercise) + inc preload (early pregnancy) inc SV
dec afterload inc SV
contractility (and thus SV) inc with
inc intracellular Ca (digitalis)
dec extracellular Na (dec activity of Na/Ca exchanger)
catecholamine stimulation with B1 receptor
phospholambin phosphorylation
contractility (and thus SV) dec with
B1 blockade (dec cAMP)
HF with systolic dysfunction
acidosis
hypoxia/hypercapnia (dec PO2, inc PCO2)
non-dihydropyridine Ca channel blockers
what happens to SV in heart failure?
dec
how is preload determined? what does it depend on?
estimated by ventricular EDV; depends on venous tone and circulating blood volume
what could decrease preload?
venous vasodilators such as nitroglycerin\
ACEis and ARBs
how does the LV compensate for increased afterload?
thickening (hypertrophy) to dec wall tension
what decreases afterload?
arterial vasodilators such as hydralazine
ACEiS and ARBs
what is used to approximate afterload?
MAP
chronic hypertension has what effect on LV?
chronic HTN > inc MAP > LV hypertrophy
what is Laplace’s law?
wall tension = pressure x radius
wall stress = pressure x radius / 2 x wall thickness
myocardial O2 demand is increased by:
CARD - increased:
Contractility
Afterload (proportional to arterial pressure)
Rate of heart
Diameter of ventricle (inc wall tension)
SV =
SV = EDV - ESV
EF =
EF = SV/EDV
CO =
CO = HR x SV
fick principle: CO = rate of O2 consumption / (arterial O2 content - venous O2 content)
PP =
PP = SBP - DBP
MAP =
MAP = CO x TPR
MAP (at resting HR) > 2/3 DBP + 1/3 SBP = DBP + 1/3 PP
EF is a measure of what? what happens to EF in heart failure?
EF is a measure of ventricular contractility
dec in systolic HF, normal in diastolic HF
what is CO maintained by?
in early stages of exercise, inc HR and inc SV
in later stages, inc HR only (SV plataeus)
what shortens diastole? what affect does shorter diastole have on CO?
inc HR (vetricular tachycardia) > dec diastolic filling time > dec SV > dec CO
PP relationship to SV and arterial compliance
PP is proportional to SV and inversely proportional to arterial compliance
PP is increased with
hyperthyroid
aortic regurg
aortic stiffening (isolated systolic HTN in elderly)
obstructive sleep apnea (inc sympathetic tone)
anemia
exercise (transient)
PP is decreased with
aortic stenosis
cardiogenic shock
cardaic tamponade
advanced HF
PP is decreased with
aortic stenosis
cardiogenic shock
cardaic tamponade
advanced HF
starling law says what
the heart’s ability to vary contractility based on blood volume;
the force of systolic contraction is directly proportional to diastolic length of cardiac muscle fiber (preload/how much blood fills ventricles during diastole)
short length of muscle fibers = low contractile force
contractility is increased by
catecholamines
positive inotropes such as digoxin, sympathetic NS
contractility is decreased by
loss of myocardium (MI)
B blockers (acutely)
non-dihydropyridine Ca channel blockers
dilated cardiomyopathy
the heart pumps ___ blood with ___ through ___ to the tissues
and recieves ___ blood with ___ through the ___
the heart pumps oxygenated blood with nutreitns through arteries
and recieves deoxygenated blood with waste products through veins
SV, EDV, ESV, etc occur in the ___ chamber
LV
the force of contraction depends on
the number of myosin heads that bind to actin > depends on the length of the overlapping section > depends on overall length of sarcomere > depends on how much blood fills ventricles during diastole
the bulbus cordis gives rise to…
smooth parts (outflow tract) or left and right ventricles
the endocardial cushion gives rise to…
atrial septum, membranous IV septum, AV and semilunar valves
the left horn of sinus venosus gives rise to…
coronary sinus
the posterior, subcardinal, and supracardinal veins gives rise to…
IVC
the primitive atrium gives rise to…
trabeculated part of left and right atria
the primitive pulmonary vein gives rise to…
smooth part of left atrium
the primitive ventricle gives rise to…
trabeculated part of left and right ventricles
the right common vardinal vein and right anterior cardinal vein gives rise to…
SVC
the right horn of sinus venosus gives rise to…
smooth part of right atrium (sinus venarum)
the truncus arteriosus gives rise to…
ascending aorta and pulmonary trunk
what is special about the heart in embryonic development?
first functional organ in vertebrate embryos
when does the heart start beating
beats spontaneously by week 4 of development
when does heart looping to establish left right polarity begin? a defect in this can cause what?
week 4 of gestation
Defect in left right Dynein > Dextrocardia (Kartagener syndrome; 1deg ciliary Dyskinesia)
separation of atrial chambers steps
septum primum grows toward endocardial cushions, narrowing foramen primum
foramen secundum forms in septum primum, foramen primum disappears
septum secondum develops as foramen secunum maintains right to left shunt
septum secondum expands and covers most of foramen secunum; remaining foramen secondum = foramen ovale. remaining septum primum = valve of foramen ovale
septum secondum and septum primum fuse > atrial septum
foramen ovale closes right after birth bc inc LA pressure and dec RA pressure
separation of ventricular chambers steps
muscular IV septum forms, opening called IV foramen
aorticopulmonary septum rotates + fuses with muscular IV septum > membranous IV septum, closing IV foramen
growth of endocardial cusions separates atria from ventricles and contributions to both atrial septation and membranous IV septum
where do neural crest and endocardial cells migrate to?
ascending aorta + pulmonary trunk
truncal and bulbar ridges that spiral and fuse to form aorticopulmonary septum
conotruncal abnormalities associated with failure of neural crest cells to migrate include:
transposition of great vessels
tetralogy of fallot
persistent truncus arteriosus
post natal derivative of allantois / urachus
median umbilical ligament
post natal derivative of ductus arteriosus
ligamentum arteriosum
post natal derivative of ductus venosus
ligamentum venosum
post natal derivative of foramen ovale
fossa ovalis
post natal derivative of notochord
nucleus pulposus
post natal derivative of umbilical arteries
medial umbilical ligaments
post natal derivative of umbilical vein
ligamentum teres hepatis (round ligament)
describe the pathway of fetal circulation
umbilical vein > ductus venosus > IVC
(oxygenated) IVC > foramen ovale > aorta > fetal head + body
(deoxygenated) IVC > SVC > RA > RV > Pulm A > ductus arteriosus > descending aorta (this shunt is due to high fetal pulmonary artery resistance, partly due to low O2 tension)
heart derives from (germ layer)
mesoderm
what effect do inotropes have on cardiac/vascular function
changes in contractility > altered SV > altered CO/VR and RA pressure (RAP)
When is viscosity increased
Hyperproteinemic states (eg multiple myeloma), polycythemia
When is viscosity decreased
Anemia
Viscosity mostly depends on
Hematocrit
Compliance =
Change in volume / change in pressure
Change in pressure =
Q (volumetric flow rate) x R (resistance)
What part of cardiac/vascular function curves shows the operating point of the heart?
The operating point of the heart (venous return and CO are equal) is at the intersection of the curves
The circulatory system is a ____ system
Closed
Capillaries have the ___ total cross sectional area and the ____ flow velocity
Capillaries have the highest cross sectional area and the lowest flow velocity
What BV accounts for most of TPR?
Arterioles
inotropy effect
Changes in contractility
> changes in SV > CO/VR > RAP
+ inotropes
Catecholamines, digoxin, exercise
- inotropes
HF with reduced EF, narcotic overdose, sympathetic inhibition
Effect of changing venous return
Changes in circulating volume
> changes in RAP > SV > CO
+ venous return
Fluid infusion, sympathetic activity
- venous return
Acute hemorrhage, spinal anesthesia
TPR changes effect
Changes in TPR
> changes in CO > changes in RAP unpredictable
+ TPR
Vasopressors
- TPR
Exercise, AV shunt
What are the phases of the left ventricle in normal cardiac function
Systole -
Isovolumetric contraction - period bw mitral closure and aortic opening
Systolic ejection - period bw aortic opening and closing
Diastole -
Isovolumetric relaxation - period bw aortic closing and mitral opening
Rapid filling - period right after mitral opening
Reduced filling - period just before mitral closing
What phase of the cardiac cycle is the period of highest oxygen consumption?
Isolvolumetric contraction
S1 is what? and where is it best heard?
S1 = mitral and tricuspid closure
Best heart mitral area
S2 is what? and where is it best heard?
S2 = aortic and pulmonic closure
Best heard left upper sternal border
S3 is heard when? What is it associated with?
S3 = early diastole during rapid ventricular filling. Associated with inc filling pressures (mitral regurgitation, HF) and common in dilated ventricles but can be normal in kids, young adults, and pregnant women
S4 is heard when? What is it associated with? how is it best heard?
S4 = late diastole “atrial kick” - high atrial pressure associated with ventricular noncompliance (eg hypertrophy); left atrium must push against stiff LV wall. Abnormal in any age.
best heart at apex with pt in left lateral decubitus position
Waves of jugular venous pulse JVP (right atrial pressure curve)
A wave - atrial contraction
C wave - RV contraction (closed tricuspid bulging into atrium)
X descent - downward displacement of closed tricuspid during rapid ventricular ejection phase.
V wave - inc right atrial pressure due to filling (“villing”) against closed tricuspid valve
Y descent - RA emptying into RV.
When is the a wave of right atrial pressure curve (JVP) absent?
Atrial fibrillation
When is the x descent of right atrial pressure curve (JVP) reduced or absent? Why?
In tricuspid regurgitation and HF because pressure gradients are reduced
When is the y descent of right atrial pressure curve (JVP) prominent?
Constructive pericarditis
pathologic changes in aortic stenosis
dec LV pressure
dec SV
inc ESV
ventricular hypertrophy > dec compliance > inc EDP for given EDV
pathologic changes in mitral regurgitation
inc EDV
inc SV
dec ESV (due to dec resistance and inc regurg into LA during sys)
no true isovolumetric phase
pathologic changes in aortic regurgitation
inc EDV
inc SV
inc PP
no true isovolumetric phase
pathologic changes in mitral stenosis
inc LAP
dec ESV
dec SV
dec EDV (due to impaired ventricular filling)
what is wide splitting and when is it seen
delayed pulmonic sound, esp on inspiration.
conditions that delay RV emptying s/a pulmonic stenosis, right bundle branch block
what is fixed splitting and when is it seen
ASD > left to right shunt > inc RA and RV vol > inc pulmonic valve flow
greatly delayed pulmonic closure, regardless of breath
what is paradoxal splitting and when is it heard
normal order of valve closure is reversed so P2 soumd occurs before delayed A2 sound so on inspiration P2 closes later and moves closer to A2, usually heard on expiration
conditions that delay aortic closure s/a aortic stenosis, left bundle branch block
what murmurs can be heard at the aortic area
All systolic
aortic stenosis
flow/physiologic murmur
aortic sclerosis
what murmurs can be heard at the left sternal border (erbs)
diastolic:
aortic regurgitation
pulmonic regurgitation
systolic:
hypertrophic cardiomyopathy
what murmurs can be heard at the pulmonic area
systolic ejection murmurs:
pulmonic stenosis
atrial septal defect
flow murmur
what murmurs can be heard at the tricuspid area
holosystolic murmurs:
tricuspid regurgitation
ventricular septal defect
distolic murmurs:
tricuspid stenosis
what murmurs can be heard at the mitral area/apex
holosystolic: mitral regurg
systolic: mitral prolapase
diastolic: mitral stenosis
what effect does the manuver of inspiration have
inc venous return to RA
inc intensity of R heart sounds
what effect does the manuver of hand grip have
inc afterload
inc intensity of MR, AR, and VSD mumurs
delays click/murmur of MVP
what effect do the manuvers of valsalva and standing up have
dec preload
dec intensity of most murmurs, inc AS
inc intensity of hypertrophic cardiomyopathy murur
earlier click for MVP
what effect does the manuver of rapid squatting have
inc venous return
inc preload
inc afterload
inc intensity of MR, AR, and VSD murmurs
dec intensity hypertrophic cardiomyopathy murmur
later click MVP
