Cardiovascular - First Aid Flashcards
The truncus arteriosus gives rise to…
the ascending aorta and pulmonary trunk.
The bulbus cordis gives rise to…
outflow track of left and right atria.
The primitive atria gives rise to…
the trabeculated part of left and right atria.
The primitive ventricle gives rise to…
the trabeculated part of the left and right ventricles.
The primitive pulmnoary vein gives rise to…
the smooth part of the left atrium.
The left horn of the sinus venous gives rise to the…
coronary sinus.
The right horn of the sinus venous gives rise to…
the smooth part of the right atrium.
The right common cardinal vein and right anterior cardinal vein give rise to…
the SVC.
In the vertebrate embryo, the heart is…
the first functional organ and it beats spontaneously by week 4.
In week 4 of gestation, the primitive heart tube will…
loop to establish left-right polarity.
A defect in left-right dynein can lead to..
dextrocardia (as seen in Kartagener).
The foramen ovale closes soon after….
birth due to increased LA pressure.
A patent foramen ovale is caused by…
failure of the septum primum and septum secundum to fuse after birth; most left untreated.
Patent foramen ovale can lead to…
paradoxical emboli (venous thromboemboli that enter the systemic arterial circulation).
Ventricular Septal Defect (VSD) most commonly occurs in..
the membranous septum.
Babies with VSD are…
acyanotic at birth due to left to right shunt.
Outflow tract is formed when truncus arteriosus rotates and neural crest and endocardial cell migrations lead to…
truncal and bulbar ridges that spiral and fuse to form the aorticopulmonary septum.
Conotruncal abnormalities include:
- transposition of the great vessels 2. tetralogy of fallot 3. persistent truncus arteriosus
The aortic and pulmonary valves are derived from…
endocardial cushions of the outflow tract.
The mitral and tricuspid valves are derived from…
fused endocardial cushions of the AV canal.
Fetal erythropoesis occurs in:
- Yolk Sac (3-8 wks) 2. Liver (6 wks - birth) 3. Spleen (10-28 wks) 4. Bone marrow (18 wks to adult)
Fetal Hb (HbF)
alpha2gamma2
Adult Hb (HbA)
alpha2beta2
HbF has higher affinity for oxygen due to…
less avid binding of 2,3-BPG. This allows HbF to extract oxygen from maternal Hb across the placenta.
Highest concentration of O2 in the fetal circulation is in…
the umbilical vein. PO2 = 30 mmHg 80% saturated w/ O2
Blood entering the fetus through the umbilical vein is conducted via the…
ductus venosus into the IVC to bypass the hepatic circulation.
Most highly oxygenated blood reaching the heart via the IVC is…
diverted through the foramen ovale and pumped out the aorta to teh head and body.
Deoxygenated blood entering the RA from the SVC goes:
RA –> RV –> main PA –> PDA –> descending aorta
PDA is kept open in the fetal period due to…
high fetal pulmonary artery resistance due partly to low O2 tension.
At birth, when the infant takes their first breath…
decreased resistance in the pulmonary circulation causes increased left atrial pressure vs. right atrial pressure clossing the foramen ovale.
The ductus arteriosus closes due to…
increase in O2 and decrease in prostaglandins (from placental separation).
PDA is kept open medically with…
PGE1 and PGE2.
The umbilical vein becomes the…
ligamentum teres hepatis contained in the falciform ligament.
Umbilical arteries become…
medial umbilical ligaments
ductus arteriosus becomes…
ligamentum arteriosum
ductus venosus becomes…
ligamentum venosum
foramen ovale becomes…
fossa ovalis
allantois becomes…
urachus-median umbilical ligament; urachal cyst or sinus is a remnant
Notochord becomes…
nucleus pulposus of intervertebral disc
SA and AV nodes are supplied by…
the RCA and infarct may cause bradycardia or heart block.
The acute marginal artery supplies…
the RV.
The posterior decending artery supplies…
the posterior third of the interventricular septum and posterior walls of ventricles.
The LAD supplies…
the anterior 2/3 of the interventricular septum, anterior papillary muslce and anterior surface of the left ventricle.
The left circumflex coronary artery supplies…
the lateral and posterior walls of the LV.
Right-dominant circulation
PDA arises from RCA
Left-dominant circulation
PDA arises from LCX
Coronary artery occlusion most commonly occurs in the….
LAD.
Coronary blood flow peaks in…
early diastole.
The most posterior part of the heart is…
the LA; enlargment can cause dysphagia or hoarseness.
CO =
SV x HR
MAP (mean arterial pressure) =
CO x TPR Also, MAP = 2/3 diastolic pressure + 1/3 diastolic pressure
Pulse pressure =
systolic pressure - diastolic pressure
Pulse pressure is proportional to…
SV and inversely proportional to arterial compliance.
SV =
EDV - ESV.
During the early stages of exercise, CO is maintained by…
increased HR and increased SV.
During the late stages of exercise, CO is maintained by…
increased HR only, the SV plateaus.
Diastole is preferentially shortened with…
increased HR leading to less filling time which decreases CO.
Increased pulse pressure is seen in (5):
- hyperthyroidism 2. aortic regurgitation 3. arteriosclerosis 4. obstructive sleep apnea 5. exercise
Decreased pulse pressure is seen in (4):
- aortic stenosis 2. cardiogenic shock 3. cardiac tamponade 4. advanced heart failure
Stroke volume is increased by…
increased contractility, increased preload and decreaed afterload.
Contractility increases with:
- catecholamines 2. increased intracellular calcium 3. decreased extracellular sodium 4. digitalis
Catecholamines increase contractility by…
increasing the activity of the Ca2+ pump in the SR
Digitalis increases contractility by…
blocking the Na/K pump leading to increased intracellular sodium leading to decreased Na/Ca exchange leading to increased intracellular Ca
Contractility decreases with (5):
- beta1-blockade (decreased cAMP) 2. heart failure with systolic dysfunciton 3. acidosis 4. hypoxia/hypercapnea 5. non-dihydropyridine Calcium channel blockers
Preload is approximated by..
ventricular EDV; it depends on venous tone and circulating blood volume.
Preload can be decreased with…
VEnodilators. (nitroglycerin)
Afterload is approximated by…
MAP.
The LV compensates for increased afterload by…
thickening to decrease wall tension.
Afterload is decreased with…
Vasodilators (Hydralazine).
Both preload and afterload are decreased by…
ACE inhibitors and ARBs.
Left ventricular EF is an index of…
ventricular contractility. Normal EF is > 55%.
EF is decreased in…
systolic heart failure and normal in diastolic heart failure.
Total resistance of vessels in series
TR = R1 + R2 + R3
Total resistance of vessels in parallel
1/TR = 1/R1 + 1/R2 + 1/R3
Viscosity depends mostly on…
hematocrit.
Viscosity increases in…
-polycythemia -hyperproteinemic states -aHereditary spherocytosis
Viscosity decreases in…
anemia.
Resistance is directly proportional to…
viscosity and vessel length and inversely proportional to the radius to the 4th power.
Most of the TPR is accounted for by…
arterioles which regulate capillary flow.
Positive Inotropes
catecholamines, digoxin
Negative Inotropes
heart failure, narcotic overdose
Things that increase volume, venous tone
fluid infusion, sympathetic activity
Things that decrease volume, venous tone
acute hemorrhage, spinal anesthesia
Things that increase TPR
vasopressors
Things that decrease TPR
exercise, AV shunt
S1
mitral and tricuspid valve closure; loudest at mitral area
S2
aortic and pulmonary valve closure; loudest at left sternal border
S3
in early diastole during rapid ventricular filling phase; associated with incresed filling pressures (MR, HCR) and is more common in dilated ventricles
S4
in late diastole; high atrial pressure; associated with ventricular hypertrophy; left atrium must push against the stiff LV wall
Normal splitting
Inspiration leads to a drop in intrathoracic pressure leading to an increase in venous return to the RV. Increased RV stroke volume leads to increased RV ejection time leading to delayed closure of the pulmonary valve.
Normal splitting is also contributed to by…
decreased pulmonary impedance.
Wide splitting is seen in conditions that…
delay RV emptying (pulmonic stenosis, right bundle branch block)
Fixed splitting is seen in…
ASD which leads to a left to right shunt which leads to increased RA and RV volumes which leads to increased flow through the pulmonic valve such that regardless of breath, pulmonic closure is greatly delayed.
Paradoxical splitting is seen in conditions that…
delay LV (aortic stenosis, left bundle branch block).
In paradoxical splitting, the normal order of valve closure is…
reversed so that P2 sound occurs before delayed A2 sound. Therefore, on inspiration, P2 closes later and moves closer to A2 (paradoxical).
Aortic area murmurs
Systolic 1. aortic stenosis 2. flow murmur 3. aortic valve sclerosis
Left sternal border murmurs
Systolic 1. Hypertrophic cardiomyopathy Diastolic 1. aortic regurgitation 2. pulmonic regurgitation
Pulmonic area murmurs
Systolic 1. pulmonic stenosis 2. flow murmur
Tricuspid area murmurs
Pansystolic 1. tricuspid regurgitation 2. VSD Diastolic 1. tricuspid stenosis 2. ASD
Mitral area murmurs
Systolic 1. mitral regurgitation Diastolic 1. mitral stenosis
ASD commonly presents with…
a pulmonary flow murmur (increased flow through the pulmonic valve) and a diastolic rumble (increased flow across the tricuspid).
Blood flow across the actual ASD does…
not cause a murmur bc there is no pressure gradient.
Inspiration maneuver will…
increase the intensity of the right heart sounds.
Hand grip (increases systemic vascular resistance) which will…
increase intensity of MR, AR, and VSD murmurs decrease the intensity of AS, hypertrophic cardiomyopathy murmurs
Valsalva (standing decreases venous return) will…
decrease intensity of most murmurs increase intensity of the hypertrophic cardiomyopathy murmur
Rapid squatting (increases venous return, increases preload, increases afterload)
decreases intensity of hypertrophic cardiomyopathy murmur increases intensity of AS murmur
Mitral Regurgitation murmur
-holosystolic, high-pitched “blowing murmur” -loudest at apex, radiates toward axilla
MR murmur is enhanced by…
maneuvers that increase TPR (squatting, hand grip).
MR is often due to…
ischemic heart disease, MVP or LV dilation.
Tricuspid regurgitation murmur
-holosystolic, high-pitched “blowing murmur” -loudest at tricuspid and radiates to the right sternal border
TR murmur is enhanced by…
maneuvers that increase RA return (inspiration).
TR is commonly caused by…
RV dilation.
Rheumatic fever and endocarditis can cause either…
MR or TR.
Aortic Stenosis murmur
-crescendo-decrescendo systolic ejection murmur -loudest at base; radiates to carotids -pulsus parvus et tardus
Aortic stenosis can lead to…
Syncope, Angina and Dyspnea on exertion
Aortic stenosis is often due to…
age-related calcific aortic stenosis or bicuspid aortic valve.
VSD murmur
-holosystolic, harsh sounding murmur -loudest at tricuspid area -accentuated with hand grip maneuver due to increased afterload
Mitral valve prolapse murmur
-late systolic crescendo murmur with midsystolic click -best heard over apex and just before S2
MVP can predispose to…
infective endocarditis.
MVP can be caused by…
myxomatous degeneration, rheumatic fever or chordae.
MVP occurs earlier with…
maneuvers that decrease venous return (standing or valsalva).
Aortic regurgitation murmur
-high pitched “blowing” early diastolic decrescendo murmur -wide pulse pressure
Aortic regurgitation can present with…
boudning pulses and head bobbing.
AR is often due to…
aortic root dilation, bicuspid aortic valve, endocarditis or rheumatic fever.
Aortic regurgitation murmur is increased during…
hand grip. Vasodilators decrease the intensity of the murmur.
Mitral stenosis murmur
-follows opening snap due to abrupt halt in leaflet motion in diastole after rapid opening due to fusion of the leaflets -delayed rumbling late diastolic murmur
With mitral stenosis, a decreased interval between S2 and the opening snap correlates with…
increased severity.
MS often occurs secondary to…
rheumatic fever. Can lead to LA dilatation.
MS murmur is enhanced by…
maneuvers that increase LA return (expiration).
PDA murmur
-continuous machine-like murmur -loudest at S2 -best heart at left infraclavicular area
PDA is often due to…
congenital rubella or prematurity.
T wave inversion may indicate…
recent MI.
U wave is caused by…
hypokalemia and bradycardia.
Speed of conduction
Purkinje > atria > ventricles > AV node
Pacemaker potential
SA > AV > bundle of His/purkinje/ventricles
Torsades de pointes is…
polymorphic ventricular tachycardia characterized by shifting sinusoidal waveforms on ECG.
Torsades de pointes can progress to…
ventricular fib.
A predisposing factor for Torsades is…
long QT interval.
Torsades is caused by…
drugs, decreased K, decreased Mg.
Treatment of Torsades is with…
magnesium sulfate.
Congenital long QT is an…
inherited disorder of myocardial repolarization typically due to ion channel defects.
2 types of Congenital long QT syndrome
- Romano-Ward Syndrome 2. Jervell and Lange-Nielsen Syndrome
Romano-Ward Syndrome features
-congenital long QT -autosomal dominant -pure cardiac phenotype