cardiology Flashcards
Truncus arteriosus GIVES RISE TO
Ascending aorta and pulmonary trunk
Bulbus cordis GIVES RISE TO
Smooth parts (outflow tract) of left and right ventricles
Endocardial cushion GIVES RISE TO
Atrial septum, membranous interventricular septum; AV and semilunar valves
Primitive atrium GIVES RISE TO
Trabeculated part of left and right atria
Primitive ventricle GIVES RISE TO
Trabeculated part of left and right ventricles
Primitive pulmonary vein GIVES RISE TO
Smooth part of left atrium
Left horn of sinus venosus GIVES RISE TO
Coronary sinus
Right horn of sinus venosus GIVES RISE TO
Smooth part of right atrium (sinus venarum)
Right common cardinal vein and right anterior cardinal vein GIVES RISE TO
Superior vena cava (SVC)
First functional organ in vertebrate embryos
heart
Primary heart tube loops to establish _____
left-right polarity
Cardiac looping begins in week ____ of gestation.
week 4
Defect in left-right dynein (involved in L/R asymmetry) can lead to ____
dextrocardia
dextrocardia seen in____
Kartagener syndrome (primary ciliary dyskinesia)
Septum secundum and septum primum fuse to form the___
atrial septum
Patent foramen ovale is caused by ____
failure of septum primum and septum secundum
to fuse after birth
Patent foramen ovale can lead to
paradoxical emboli
abnormalities associated with failure of neural crest cells to migrate:
-Transposition of great vessels.
-Tetralogy of Fallot.
-Persistent truncus arteriosus.
Aortic/pulmonary valve derived from ___
endocardial cushions of outflow tract
Mitral/tricuspid valve derived from ___
fused endocardial cushions of the AV canal.
3 important fetal circulation shunts:
1 Ductus venosus
2 Foramen ovale
3 Ductus arteriosus
Blood entering fetus through the___
umbilical vein
Blood entering fetus through the umbilical vein is conducted via the _____
ductus venosus
Blood entering fetus through the umbilical vein is conducted via the ductus venosus into the ____
IVC
Blood entering fetus through the umbilical vein is conducted via the ductus venosus into the IVC, bypassing ____
hepatic circulation
Most of the highly oxygenated blood reaching the heart via the ____
IVC
Most of the highly oxygenated blood reaching the heart via the IVC is directed through the __
foramen ovale
Most of the highly oxygenated blood reaching the heart via the IVC is directed through the foramen ovale and pumped into the ___
aorta
Most of the highly oxygenated blood reaching the heart via the IVC is directed through the foramen ovale and pumped into the aorta to supply the ____
head and body
Deoxygenated blood from the SVC passes through the RA -> RV ->____ -> ___ -> ___
main pulmonary artery
patent ductus arteriosus
descending aorta
At birth, infant takes a breath; ___ resistance
in pulmonary vasculature, causing ___ left atrial pressure vs right atrial pressure, causing ____ to close
↓
↑
foramen ovale
At birth, infant takes a breath… __ O2 (from respiration) and ___ prostaglandins (from placental separation) leads to closure of ____
ductus arteriosus
Indomethacin helps ___
close PDA
remnant of ductus arteriosus)
ligamentum arteriosum
Prostaglandins E1 and E2
kEEp PDA open
SA and AV nodes are usually supplied by ___
Right coronary artery (RCA)
RCA supplies ___
SA and AV nodes
Right-dominant circulation %
85%
Right-dominant circulation (85%) = PDA arises from __
RCA.
Left-dominant circulation ___
(8%)
Left-dominant circulation (8%) = PDA arises from ___
Left circumflex coronary artery (LCX)
Codominant circulation (7%) = PDA arises from both ____ and ___
LCX and RCA
Coronary artery occlusion most commonly occurs in the ___
Left anterior descending
artery (LAD)
Coronary blood flow peaks in __
early diastole
most posterior part of the heart
left
atrium
left
atrium enlargement can cause ___ (due to compression of the ___) or ___ (due to compression of the____, a branch of the ___).
dysphagia
esophagus
hoarseness
left recurrent laryngeal nerve
vagus
Pericardium consists of 3 layers (from outer to inner):
1) Fibrous pericardium 2) Parietal layer of serous pericardium 3) Visceral layer of serous pericardium
Pericardial cavity lies between __ and
__ layers.
parietal
visceral
stroke volume (SV) × heart rate (HR)
CO
Fick principle:
CO = rate of O2 consumption/
arterial O2 content − venous O2 content
Mean arterial pressure (MAP) =
CO × total peripheral resistance (TPR)
2 ⁄3 diastolic pressure + 1⁄3 systolic pressure =
MAP
Pulse pressure =
systolic pressure – diastolic pressure
Pulse pressure is proportional to ___ and inversely proportional to ___
SV
arterial compliance
proportional to SV, inversely proportional to arterial compliance.
Pulse pressure
SV =
= (EDV) − (ESV)
During the early stages of exercise, CO is maintained by ___
↑ HR
and
↑ SV
During the late stages of exercise, CO is maintained by ___
↑ HR only (SV plateaus)
Diastole is preferentially shortened with ___ causing ___ filling time leading to ___ (eg, ventricular tachycardia).
↑ HR
less
↓CO
Inc. in pulse pressure is seen in ___
hyperthyroidism
aortic regurgitation
Dec. pulse pressure is seen in ___
aortic stenosis
cardiogenic shock
cardiac tamponade
HF
↑ SV with: “SV CAP”
↑ Contractility (eg, anxiety, exercise)
↑ Preload (eg, early pregnancy)
↓ Afterload
Contractility (and SV) ↑ with:
Catecholamines
increased intracellular Ca2+
↓ extracellular Na+
Catecholamines (inhibition of
___ ) →__ Ca2+ entry into__→Ca2+ induced ___ release)
phospholamban
increase
sarcoplasmic reticulum
Ca2+
Contractility (and SV) ↓ with:
- β1-blockade ( dec. cAMP)
- HF with systolic dysfunction
- Acidosis
- Hypoxia/hypercapnia
- Non-dihydropyridine Ca2+ channel blockers
↑ MyoCARDial O2 demand is ↑ by:
__ Contractility
__ Afterload (proportional to ___) heart Rate
__ Diameter of ventricle (__ wall tension)
↑ Contractility
↓ Afterload
arterial pressure
↑ Diameter of ventricle
↑ wall tension
Preload approximated by ___
ventricular EDV
VEnodilators (eg, ___) …. __ preload
nitroglycerin
↓ preload
Afterload approximated by ___
MAP
LV compensates forafterload by ___ in order to __ wall tension
thickening (hypertrophy)
↓
VAsodilators (eg, ___) …. ___ Afterload (Arterial).
hydrAlAzine
↓
ACE inhibitors and ARBs both ____ preload and afterload.
↓
Chronic hypertension (__MAP) leads to ___.
increases
LV hypertrophy.
Left ventricular EF is an index of ____
ventricular contractility
normal EF is ___
≥ 55%
EF ___ in systolic HF.
EF ___ in diastolic HF.
↓
normal
Force of contraction is proportional to ___
preload
increase contractility with ___
- catecholamines
- positive inotropes (eg, digoxin)
decrease contractility with ___
- loss of myocardium (eg, MI)
- β-blockers (acutely)
- non-dihydropyridine Ca2+ channel blockers
- dilated cardiomyopathy
ΔP =
Q × R
a change in pressure in a vessel is equal to flow times resistance
this is similar to Ohm’s law where a change in voltage is equal to current times resistance: ΔV = IR
Volumetric flow rate (Q) =
flow velocity (v) × cross-sectional area (A)
Resistance
(driving pressure ΔP) / (flow Q) = 8η (viscosity) x length / (πr4)
Total resistance of vessels in series:
RT = R1 + R2 + R3 . . .
Total resistance of vessels in parallel:
1/RT = 1/R1 + 1/R2 + 1/R3
Viscosity depends mostly on ____
hematocrit
Viscosity increases in ____ states (eg,
_____ ) and _____
hyperproteinemic states (eg, multiple myeloma)
polycythemia
Viscosity decreases in ____
anemia
Removal of organs in parallel arrangement (eg, ____) = ___TPR and ___CO.
nephrectomy
↓ TPR
increase CO
Pressure gradient drives flow from __ pressure to ___ pressure.
high
low
____ account for most of TPR.
Arterioles
___ provide most of blood storage capacity.
Veins
Inotropy curve Effects
Changes in contractility → altered CO for a given RA pressure (preload) or EDV.
⊕ Intropy
Catecholamines
digoxin
⊝ Intropy
Uncompensated HF
narcotic overdose
Venous return curve Effects
Changes in circulating volume or venous tone → altered RA pressure for a given CO.
Mean systemic pressure (x-intercept) changes with volume/venous tone.
⊕ volume, venous tone
Fluid infusion, sympathetic activity
⊝ volume, venous tone
Acute hemorrhage
spinal anesthesia
Total peripheral resistance curve Effects
At a given mean systemic pressure (x-intercept) and RA pressure, changes in TPR → altered CO.
⊕ TPR
Vasopressors
⊝ TPR
Exercise
AV shunt
exercise: __ inotropy and ___ TPR to maximize ___
↑
↓
CO
HF: ___ inotropy → fluid retention to __ preload to maintain ___
↓
↑
CO
fetal erythropoiesis WK 3-10
yolk sac
fetal erythropoiesis WK 6-birth
liver
fetal erythropoiesis WK 15-30
spleen
fetal erythropoiesis WK 22-adult
bone marrow
fetal hemoglobin
A2Y2
adult hemoglobin
A2B2
truncal and bulbar ridges spiral and fuse to form
aorticopulmonary septum
___ separates the ascending aorta and pulmonary trunk
aorticopulmonary septum
aorticopulmonary septum formed from ___
cardiac neural crest
notocord postanatal called ___
nucleus pulposus
foramen ovale postnatal called ____
fossa ovalis
period between mitral valve closing and aortic valve opening;
Isovolumetric contraction
period between aortic valve opening and closing
Systolic ejection
period between aortic valve closing and mitral valve opening
Isovolumetric relaxation
period just after mitral valve opening
Rapid filling
period just before mitral valve closing
Reduced filling
period of highest O2 consumption
Isovolumetric contraction
4 phases of cardiac cycle :
- Isovolumetric contraction
- Systolic ejection
- Isovolumetric relaxation
- Rapid filling
- Reduced filling
mitral and tricuspid valve closure. heart sound?
S1
S1 loudest at _____
mitral area
S2 Loudest at ____
left upper sternal border.
aortic and pulmonary valve closure. heart sound?
S2
in early diastole during rapid ventricular
filling phase. heart sound?
S3
heart sound associated withfilling pressures (eg, mitral regurgitation, HF) and more common in dilated ventricles (but can be normal in children and young adults).
S3
late diastole (“atrial kick”). heart sound?
S4
heart sound best heard at apex with patient in left lateral decubitus position.
S4
heart sound associated with ventricular noncompliance (eg, hypertrophy). Left atrium must push against stiff LV wall. Consider abnormal, regardless of patient age.
S4
[JVP] a wave—
atrial contraction
Absent in atrial fibrillation (AF). [JVP]
a wave
c wave— [JVP]
RV contraction (closed tricuspid valve bulging into atrium).
x descent— [JVP]
atrial relaxation and downward
displacement of closed tricuspid valve during ventricular contraction.
Absent in tricuspid regurgitation. [JVP]
x descent
Prominent in tricuspid insufficiency and right HF. [JVP]
x descent
v wave— [JVP]
right atrial pressure due to filling (“villing”) against closed tricuspid valve.
y descent— [JVP]
RA emptying into RV
Prominent in constrictive pericarditis [JVP]
y descent
absent in cardiac tamponade. [JVP]
y descent
Continuous machine-like murmur. Loudest at S2. Often due to congenital rubella or prematurity.
Patent ductus arteriosus
Best heard at left infraclavicular area.
Patent ductus arteriosus
Holosystolic, harsh-sounding murmur. Loudest at tricuspid area.
Ventricular septal defect
continuous heart murmur
Patent ductus arteriosus
Diastolic heart murmurs:
Aortic regurgitation
Mitral stenosis
Systolic Heart murmurs:
Aortic stenosis
Mitral/tricuspid regurgitation
Mitral valve prolapse
Ventricular septal defect
Crescendo-decrescendo systolic ejection murmur
Aortic stenosis
murmur Loudest at heart base; radiates to carotids.
Aortic stenosis
murmur with “Pulsus parvus et tardus”—pulses are weak with a delayed peak.
Aortic stenosis
murmur Can lead to Syncope, Angina, and Dyspnea on exertion (SAD).
Aortic stenosis
Murmur most commonly due to age- related calcification in older patients (> 60 years old) or in younger patients with early-onset calcification of bicuspid aortic valve.
Aortic stenosis
Holosystolic, high-pitched “blowing murmur.”
Mitral/tricuspid regurgitation
murmur loudest at apex and radiates toward axilla.
Mitral regurgitation
murmur is often due to ischemic heart disease (post-MI), MVP, LV dilatation.
Mitral regurgitation
murmur loudest at tricuspid area and radiates to right sternal border
tricuspid regurgitation
murmur commonly caused by RV dilatation.
tricuspid regurgitation
Rheumatic fever and infective endocarditis can cause what murmurs?
Mitral regurgitation
tricuspid regurgitation
Late systolic crescendo murmur with midsystolic click (MC; due to sudden tensing of chordae tendineae).
Mitral valve prolapse
Murmur most frequent valvular lesion.
Mitral valve prolapse
Murmur loudest just before S2. Usually benign.
Mitral valve prolapse
Murmur best heard over apex.
Mitral valve prolapse
murmur can predispose to infective endocarditis.
Mitral valve prolapse
murmur can be caused by myxomatous degeneration (1° or 2° to connective tissue disease such as Marfan or Ehlers-Danlos syndrome), rheumatic fever, chordae rupture.
Mitral valve prolapse
High-pitched “blowing” early diastolic decrescendo murmur. Long diastolic murmur, hyperdynamic pulse, and head bobbing when severe and chronic. Wide pulse pressure.
Aortic regurgitation
murmur often due to aortic root dilation, bicuspid aortic valve, endocarditis, rheumatic fever. Progresses to left HF.
Aortic regurgitation
murmur follows opening snap (OS; due to abrupt halt in leaflet motion in diastole, after rapid opening due to fusion at leaflet tips).
Mitral stenosis
murmur with delayed rumbling late diastolic murmur (interval between S2 and OS correlates withseverity). LA»_space; LV pressure during diastole.
Mitral stenosis
murmur often occurs 2° to rheumatic fever. Chronic MS can result in LA dilatation.
Mitral stenosis
rapid upstroke and depolarization—voltage-gated Na+ channels open.
Myocardial action potential Phase 0
initial repolarization—inactivation of voltage-gated Na+ channels. Voltage-gated K+ channels begin to open.
Myocardial action potential Phase 1
plateau—Ca2+ influx through voltage-gated Ca2+ channels balances K+ efflux. Ca2+ influx triggers Ca2+ release from sarcoplasmic reticulum and myocyte contraction.
Myocardial action potential Phase 2
rapid repolarization—massive K+ efflux due to opening of voltage-gated slow K+ channels and closure of voltage-gated Ca2+ channels.
Myocardial action potential Phase 3
resting potential—high K+ permeability through K+ channels.
Myocardial action potential Phase 4
In contrast to skeletal muscle …Cardiac muscle: (3 differences)
- 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.
Occurs in the SA and AV nodes only
Pacemaker action potential
upstroke—opening of voltage-gated Ca2+ channels. Fast voltage-gated Na+ channels are permanently inactivated because of the less negative resting potential of these cells. Results in a slow conduction velocity that is used by the AV node to prolong transmission from the atria to ventricles.
Phase 0
what 2 phases are absent in Pacemaker action potential
Phases 1 and 2
inactivation of the Ca2+ channels andactivation of K+ channelsK+ efflux.
Phase 3
slow spontaneous diastolic depolarization due to If (“funny current”). If channels responsible for a slow, mixed Na+/K+ inward current; different from Ina in phase 0 of ventricular action potential. Accounts for automaticity of SA and AV nodes.
Phase 4
The slope of phase 4 in the SA node determines
HR
ACh/adenosine ___ the rate of diastolic depolarization and ___HR
↓
↓
catecholamines ___ depolarization and ___ HR
↑
↑
Conduction pathway
SA node → atria→ AV node→bundle of His→right and left bundle branches→Purkinje fibers→ventricles
SA > AV > bundle of His/ Purkinje/ventricles.
Pacemaker rates
Purkinje > atria > ventricles > AV node.
Speed of conduction
Long QT interval predisposes to ____
torsades de pointes.
Polymorphic ventricular tachycardia, characterized by shifting sinusoidal waveforms on ECG; can progress to ventricular fibrillation (VF)
torsades de pointes.
Torsades de pointes caused by
drugs,
↓ K+
↓ Mg2+
congenital abnormalities
Torsades de pointes tx
magnesium sulfate
Drug-induced long QT (ABCDE):
AntiArrhythmics (class IA, III)
AntiBiotics (eg, macrolides)
Anti“C”ychotics (eg, haloperidol)
AntiDepressants (eg, TCAs)
AntiEmetics (eg,ondansetron)
Inherited disorder of myocardial repolarization, typically due to ion channel defects
Congenital long QT syndrome
in Congenital long QT syndrome there is ↑ risk of ____ due to torsades de pointes.
sudden cardiac death (SCD)
Congenital long QT syndrome 2 types:
Romano-Ward syndrome
Jervell and Lange-Nielsen syndrome
Congenital long QT syndrome type that is “autosomal dominant, pure cardiac phenotype (no deafness).”
Romano-Ward syndrome
Congenital long QT syndrome type that is “autosomal recessive, sensorineural deafness.”
Jervell and Lange-Nielsen syndrome
Brugada syndrome genetically ___
Autosomal dominant disorder
Brugada syndrome most common in ___
Asian males
ECG pattern of pseudo-right bundle branch block and ST elevations in V1-V3.risk of ventricular tachyarrhythmias and SCD
Brugada syndrome
Prevent SCD with ____
implantable cardioverter-defibrillator (ICD).
Most common type of ventricular pre- excitation syndrome.
Wolff-Parkinson-White syndrome
Wolff-Parkinson-White syndrome ECG findings:
- characteristic delta wave
- widened QRS complex
- shortened PR interval
Abnormal fast accessory conduction pathway from atria to ventricle (bundle of Kent) bypasses the rate-slowing
AV nodeventricles begin to partially depolarize earlier
Wolff-Parkinson-White syndrome
Wolff-Parkinson-White syndrome- May result in reentry circuit… leading to ___
supraventricular tachycardia.
