Exam 1 Flashcards
What is the most superficial layer of the pericardium?
fibrous pericardium
What is the most interior layer of the pericardium?
visceral pericardium
Pericardial fluid lies between which two layers of the pericardium?
parietal and visceral layer of serous pericardium
What happens to intracardiac pressure with acute increase in pericardial fluid?
CVP, PAD, and PAOP equalize and increase
What are causes of acute increased pericardial fluid?
1 tamponade dissection
What are causes of chronic increases in pericardial pressure
pericarditis
How does chronic increase in pericardial pressure change intrathoracic pressure.
Overtime cardiac sac stretches and pressures equalize
What do gap junctions facilitate?
conduction of the action potential from one cell to another
Why are there large amounts of mitochondria in the myocardium?
Lots of ATP is needed for the constant contraction of myocardium and high energy demands.
What structures of the myocardium allow for rapid release and reabsorption of Ca?
T-tubular system and sarcoplasmic reticulum
What is used treat hyperkalemia to raise the threshold potential and decrease arrhythmia?
Calcium
What separates the atria and ventricles?
coronary sulcus
what separates the RV and LV and descends from the coronary sulcus to the apex?
Interventricular sulci
Where do the coronary and posterior interventricular sulci meet?
Crux
What blood vessel lies in the anterior inter ventricular sulci?
LAD
What blood vessel drains the myocardium?
coronary sinus, O2 poor
Describe the anterior and posterior walls of the RA?
trabeculated anterior smooth posterior
What does the moderator band of the trabeculae carneae in the RV carry?
right branch of the AV bundle
What chamber of the heart provides 20-30% of LVEDV? “atrial kick’
LA
Does the LA receive blood from pulmonary arteries or veins?
veins
Where are clots likely to form in the LA?
atrial appendage
The majority of the LV septum is covered with…?
trabeculae carneae
Where is the tricuspid valve
between the RA and RV
Where is the mitral valve?
between the LV and LA
What is the normal area of the tricuspid valve?
7cm
Symptoms of tricuspid stenosis occur when the valve is?
< 1.5cm
Label the leaflets of the tricuspid valve.
What are the three leaflets of the tricuspid?
anterior, septal, and posterior
what is the normal area of the mitral valve?
4-6cm
what are the two leaflets of the mitral valve?
Anteromedial leaflet Posterolateral leaflet
Label the leafets of the mitral valve
When do symptoms of mitral stenosis appear?
valve area decreased by half, 2-3cm
What valve is the gateway to the body?
aortic valve
what is the normal area of the aortic valve?
2.5-3.5 cm
what are the cusps of the aortic valve?
Right coronary cusps Left coronary cusps Noncoronary cusps
what are the locations of the aortic cusps?
right is 11-3, non coronary is 3-7, left coronary is 7-11
When do symptoms of aortic disease appear?
Reduction of area by 1/3 to 1/2
What is the Keith Flack node?
the SA node
What part of the conduction system is located along the EPICARDIAL surface at the junction of the SVC and RA
SA node (Keith flack)
What are the two cell types of the SA node?
pacemaker and transitional
Which SA node cells initiate an action potential and which propagates the action potential?
pacemaker initiate transitional propagate
what is the intrinsic rate of the SA node>
60-100
What artery supplies the SA node?
PDA
Which internodal tract is called bachmans bundle?
anterior internodal
Where does the anterior internodal (bachmanns) tract transmit the signal from the SA node?
sends fibers to the LA and then travels down through the atrial septum to the AV node
Which internodal tract is called wenckebach tract?
middle internodal tract
Where does the middle internodal (wenckebach) tract transmit the signal from the SA node?
curves behind the SVC before descending to the AV node
Which internodal tract is called thorel tract?
posterior internodal tract
Where does the posterior internodal (thorel) tract transmit the signal from the SA node?
continues along the terminal crest to enter the atrial septum and then passes to the AV node
Which part of the conduction system is located beneath the ENDOCARDIUM on the right side of the atrial septum, anterior to the opening of the coronary sinus
AV node
The AV node is able to slow the action potential because theses cells make up the AV node.
vagal cells
what is the intrinsic firing rate of the AV node?
40-55
What is the other name for the AV bundle?
bundle of his
Where does the AV bundle transmit signals?
Extends from the lower end of the AV node and enters the posterior aspect of the ventricle and the Purkinje system
What is the preferential channel for conduction of the action potential from atrium to ventricles?
AV bundle
what is the intrinsic firing rate the AV bundle?
25-40
Ischemia of the anterolateral wall, posterior ventricular wall, and anterior papillary muscle would affect which purkinje fascicle?
anterior fascicle of the Left bundle branch
Ischemia to the lateral and posterior ventricular wall and the posterior papillary muscle would affect with purkinje fascicle?
posterior fascicle of the left bundle branch?
where does the right bundle branch of the purkinje system travel?
under the endocardium along the right side of the ventricular septum to the base of the anterior papillary muscle
What is the intrinsic firing rate of the purkinje system?
25-40
What is the most common PRE-EXCITATION syndrome?
WPW
What are EKG findings of WPW?
DELTA WAVE Short PR Wide QRS
Describe orthodromic AVNRT?
more common Narrow QRS
How do you treat orthodromic AVNRT?
block AV node with: Amiodarone Cardioversion Vagal maneuveur adenosine BB verapamil
Describe antidromic AVNRT?
more dangerous Wide QRS
How do you treat antidromic AVNRT?
block accessory pathway Amiodarone Cardioverison Procainamide
Where are K, Cl, and Na most abundant?
K inside Na, Cl outside
What ion is responsible for RMP?
Potassium
Is the Na/K pump active or passive?
Active, requires ATP.
What electrolytes are responsible for the ventricular action potential?
phase 0: Na phase 1: K, Cl phase 2, Ca, K phase 3: K Phase 4: Na/K ATPase
Why does hyperkalemia increase RMP?
potassium doesnt leak out of the cell, lack of gradient
What describes absolute refractory period?
Phase 0-3 lasts until membrane potential drops below -60mV
What describes relative refractory period?
middle of phase 3 to beginning of phase 4 -60mV to -90mV
What causes the SA node to have a higher resting membrane potential?
more permeable to Na
What electrolytes are responsible for the SA node action potential?
Phase 4: Na, Ca (t-type) Phase 0: Ca (l-type) Phase 3: K
What determines HR?
rate of spontaneous phase 4 depolarization
What catecholamines change phase 4 depolarization?
Epi, NE increase acetylcholine decreases
what is the volume of coronary blood flow?
225-250mL/min, 4-7% CO
Autoregulation of coronary blood flow is maintained between what values?
60-140
What happens when the MAP is outside autoregulatory range?
pressure dependent
what is myocardial oxygen extraction ratio?
70%
When does coronary filling take place?
diastole
How does increased HR affect coronary blood flow?
decreases filling time and decrease supply
What are the main branches of the left main?
LAD and Circumflex
What does the LAD supply?
1st Diagnal 1st septal perforator
What does the circumflex supply?
Sinus node artery (40-50% of the population) Left atrial circumflex artery Anterolateral marginal artery Distal circumflex artery Posterolateral marginal artery PDA (10-15% of the population)
What parts of the heart does the LAD supply?
anterior 2/3 of inter ventricular septum L bundle branches anterior LV
What vessel provides blood flow to the lateral LV?
Circumflex
What does the right main supply?
Conus artery Sinus node artery (50-60% of the population) Anterior right ventricular branches Right atrial branches Acute marginal branches AV node artery (90%) Proximal bundle branches PDA (most common) Terminal branches
What parts of the heart does the RCA supply?
SA node (80%) Right atrium Right ventricle Posterior 1/3 of the interventricular septum Inferior LV
What determines coronary artery dominance?
which blood vessel supplies the PDA
What rhythm would you expect to see with an occluded dominant artery?
CHB, ST elevation
Where does the coronary sinus drain?
RA
Rate of blood flow within a vessel is determined by what?
change in pressure within the vessel/resistance
How is Coronary perfusion pressure calculated?
AoDBP - LVEDP
What happens to blood flow to the subendocardium during systole?
decreases
What intrinsic factors affect coronary artery tone?
anatomic arrangement and perfusion pressure
what extrinsic factors affect coronary artery tone?
compressive factors, w/in myocardium, metabolic, neural and humoral
Coronary blood flow is mainly determined by what two factors?
O2 supply and demand
How do we increase O2 delivery?
increase blood flow
what is the biggest determinant of myocardial O2 supply and demand?
Heart rate
What affects myocardial O2 supply? (4)
coronary artery anatomy diastolic pressure diastolic time (HR) O2 extraction (Hgb, SaO2)
What affects O2 demands?
HR preload (wall stress) afterload contractility
What vasodilators released by the myocardium increase coronary flow 3-4x? (7)
Adenosine NO PGE H+ CO2 Bradykinin K+
How does O2 affect coronary vascular resistance??
increases resistance
How is CaO2 calculated?
(Hgb x 1.36 x SpO2) + (0.003 x PaO2)
How is DO2 calculated?
CO x [(Hgb x 1.36 x SpO2) + (0.003 x PaO2) x 10]
What is normal CaO2?
20
What is normal DO2?
1000
What are the bipolar leads of an EKG?
I, II, III (+ and - electrode)
What are the unipolar leads of an EKG?
aVR, aVL, AVF (+ electrode)
What are the 6 precordial leads?
V1-V5 (horizontal plane)
Explain the R wave progression (from negative deflection to positive deflection) of the precordial leads?
Due to placement Electrical activity is moving away from V1 and V2 (negative deflection), V3 neutral, V4-V5 positive deflection (towards electrode)
What leads monitor the interventricular septum?
V1, V2
What leads monitor the inferior wall?
II, III, aVF
What leads monitor the anterior wall?
V3, V4
What leads monitor the anterolateral wall?
What leads monitor the lateral wall?
I, aVL, aVR
Leads II, III, and aVF monitor ischemia of which coronary artery?
RCA
Leads I, aVL, V5, V6 monitor for ischemia of which coronary artery?
Circ
Leads V3, V4 monitor for ischemia of which coronary artery?
LAD
The anterior wall is fed by which coronary artery?
LAD
The inferior wall is fed by which coronary artery?
RCA
The lateral wall is fed by which coronary artery?
Circ
What leads determine axis deviation?
I, aVF
What is the axis deviation of a postitive deflection of lead I and postive in lead aVF?
Normal
What is the axis deviation of a postitive deflection of lead I and negative on lead aVF?
Left axis deviation
What is the axis deviation of a negative deflection of lead I and postive on lead aVF?
Right axis deviation
What is the axis deviation of a negative deflection of lead I and negative on lead aVF?
Extreme right axis
What helps determine axis deviation?
Negative deflection points to deviation side
How do vectors point to hypertrophied and infarcted myocardium?
point towards hypertrophied myocardium
point away from infarcted myocardium
What causes Right axis deviation?
COPD, acute bronchospasm, cor pulmonale, P. HTN, P. elmbolus
What causes Left axis deviation? (5)
chronic HTN, LBBB, AoV stenosis, AoV regurgitation, MV regurg
For left axis deviation think…
Pressure
For right axis deviation think…
Lung disease
what is the normal direction of depolarization of interventricular septum
left to right
what causes the R’ wave in RBBB?
RV has a delayed depolarization
Describe depolariation in LBBB?
RV depolarizes before the LV
downward deflection wide S wave (very small R wave)
Which BBB will have a wide QRS?
LBBB
What causes a LBBB?
MI, cardiomyopathy, myocarditis, HTN
What causes a RBBB?
congentital, PE, Pulm. HTN, Myocarditis, MI, age
Whichi BBB is more concerning and which is more benign?
LBBB more concerning
RBBB benign
What leads do you look for a BBB?
V1
QRS longer than 0.12 (3 small boxes)
whats the formula for CO?
HR x SV
What determines SV? (3)
preload, afterload, contractility
What estimates preload of the LV?
CVP
How is afterload calculated?
SVR =( (MAP-CVP)/ CO ) x 80
Contractility is independent of what?
preload and afterload
What is the formula for Cardiac output?
HR x SV
What is the formula for CI?
CO / BSA
What is the formula for MAP?
(SBP + 2DBP) / 3
What is the formula for Stroke volume?
CO x (1000x HR)
EDV-ESV
What is the formula for SVI?
SVR / BSA
What is the formula for SVR?
[(MAP-CVP) / CO] x 80
What is the formula for PVR?
[(MPAP - PCWP) / CO] x 80
What is the formula for EF?
(SV/EDV) x 100
What reflex is forced expiration against a closed glottis?
Valsalva
What are the afferent nerves of the valsava refelx?
Herings, CN 9, CN 10
What is the control center of the valsalva refelx?
vasomotor center in the medulla
What is the response of the valsalva reflex?
Inhibit SNS, stimulate PNS
decrease HR, contractility, BP
Hypotension during induction would activate which reflex?
baroreceptor
Where are mediators of the baroreceptor reflex located?
stretch receptors in the carotid sinus and aortic arch
What is the baroreceptors response to HTN and HoTN?
HTN -> decreased HR, BP
Describe the occulocardiac reflex.
5 and dime reflex): traction on the extraocular muscles (media rectus), conjunctiva, or orbital structures results in decreased BP, HR and arrythmias
What is the afferent pathway of the oculocardiac reflex?
long/short ciliar nerves of CN 3 -> CN 5 -> gasserian ganglion
What is the celiac reflex?
traction on the mesentery or the gallbladder or stimulation of the vagus nerve in other areas of the body
What are symtpoms of the celiac relfex?
bradycardia, apnea, hypotension
What is the stimulus of the brainbridge reflex
increased volume of blood in the heart leading to SNS stimulation
What are the sensors of the bainbridge reflex?
stretch receptors in RA, VC, and pulmonary veins
What are the afferent, control center, and efferent pathways of the bainbridge reflex?
Afferent: vagus
Control: medulla
Efferent: vagus
What relfex is activated when the heart is empty?
Bezold-Jarisch
What is the stimulus for the BJ reflex?
low venous return or MI
What is the afferent, control and response of the BJ reflex?
Afferent: vagus
control: medulla
Response: decrease HR, BP, coronary vasodilation
What are potential causes of a wide pulse pressure on A-line?
Aortic regurg, hypovolemia, sepsis
What are potential causes of a narrow pulse pressure on A-line
AS
tamponade
What does the location of the dicrotic notch on A-line tell you?
High: high SVR
Low: vasodilated
Where is closure of the aortic valve represented on the A-line tracing?
Dicrotic notch
What does systolic upstroke demonstrate on A-line?
ventricular ejection
What does a steep systolic upstroke tell you?
gradual upstroke?
steep: vasodilated
gradual: stenosis
What causes pulsus tardus et parvus?
conditions that decrease SV
narrow pulse pressure
elevated SVR
What valve lesion causes pulsus tardus et parvus?
aortic stenosis
What happens to arterial line waveform morphology as you move away from the aortic root?
SBP increases
DBP decreases
MAP constant
Pulse pressure widens
If the patient has three arterial lines one in the brachial artery, femoral artery and dorsalis pedis. Which waveform would have the highest peak systolic pressure?
DP
What causes the dicrotic notch on the A-line?
closure of the Aovalve
When are the coronary arteries perfused?
diastolic run-off
How does vasodilation and vasocontriction affect the time it takes to get to end-distolic pressure?
vasodilation will cause a steep decline (reach DBP sooner)
vasoconstriction will cause a gradual decline in DBP (reach DBP slower)
Which internal jugular vein has the higher risk for lacteration of the brachiocephalic vein or SVC?
left
Where should the IJ catheter lie?
above the junction of the SVC and RA
What are the postitive deflection and negative deflections of a CVP waveform?
positive: A, C, V
negative X, Y
On the CVP waveform which deflections occur during diastole and systole?
systole: C, X, Y
Diastole: A, Y
What do each of the CVP waveforms represent?
A- Atrial contraction
C- tricuspid elevation into the RA
X- downward movement of the contracting RV
V- back pressure from blood filling the RA
Y- tricuspid opens in early V. diastole
What is CVP a function of?
intravascular volume, venous tone, RV compliance
What conditions cause a high CVP?
hypervolemia, RV failure, TV stenosis or regurg, pulm stenosis, pulm HTN, PEEP, VSD, constrictive pericarditis, tamponade
what conditions lower CVP?
hypovolemia
What zone of the lung gives accurate PA pressures? Why?
Zone 3
continuous column of blood flow b/w the PAC and LV
Pa > Pv > PA
What are the zones of the lungs and describe the pressure differences between the zones?
Zone I = Dead Space : PA>Pa>Pv
Zone II = Waterfall: Pa > PA > Pv
Zone III = Pa > Pv > PA
what are contraindications for a PAC?
RBBB, TV disease, Right mass, mechanical Pulmonary valve
What BBB is a contraindication to PAC?
LBBB, causes a RBBB -> CHB
What are the waveforms of the PCWP?
A wave: atrial contraction
C wave: closure/bulge of MV d/t LV systole (isovolumetric contraction)
X descent: atrial distole
V wave: passive atrial filling
Y descent: passive atrial empyting
What are the distances for central line placement?
What causes loss of an A wave?
a fib, V pacing
What causes large A waves?
TV/MV stenosis
Diastolic dysfunction
MI
ventricular hypertrophy
AV dissociation
Junctional rhythm
PVC
CHB
What cause large V waves?
Tricuspid/Mitral regurg, acute intravascular volume increase, RV papillary muscle ischemia
Label the Waves.
When does PWP overestimate LVEDV?
MR, MS, increased intrathoracic pressure, pulm HTN, not in zone 3
When does PCWP underestimate LVEDV?
Chronic Aortic Insufficiency
RBBB
What is the assumption made with PAC regarding pressures?
CVP = PADP = PAOP = LAP = LVEDP = LVEDV
When does CVP not equal PADP
Change in RV compliance
Tricuspid valve disease
When does PADP not equal PAOP?
Pulmonary HTN
MR or AR
Lung zone I or II
Tachycardia
ARDS
RBBB
When does PAOP not equal LAP?
Juxtacardiac pressure (PEEP)
Lung zone I or II
Mediastinal fibrosis
RBBB
when does LAP not equal LVEVP?
Juxtacardiac pressure (PEEP)
Mitral valve disease
Change in LV compliance
When does LVEDP not equal LVEDV?
PEEP
v. interdependence
Change in LV comliance
What determines SvO2?
Pulmonary function (SaO2)
Cardiac function (CO = Q)
Oxygen delivery
Tissue perfusion
Oxygen consumption (VO2 = 250ml/min)
Hemoglobin concentration (Hgb)
What is the equation for SvO2?
SvO2 = SaO2 – (VO2/(Q x 1.34 x Hgb) x 10)
What decreases SvO2?
increased O2 consumption (stress, pain , thyroid storm, shivering, fever) and decreased O2 delivery
What increases SvO2?
decreased consumption: hypothermia, cyanide toxicity
increased delivery: increased PaO2, increased Hgb, increased CO
How do you treat SvO2?
With aortic stenosis you would expect to see what derangement on the arterial waveform?
Wide pulse pressure
Lower dicrotic notch
Steep slope of the systolic upstroke
narrow pulse pressure
(narrow) pulse pressure
(higher) dicrotic notch
(gradual) slope of the systolic upstroke
narrow pulse pressure
The area under the curve correlates with what:
SBP
DBP
MAP
SVR
MAP
What happens to the tracing as you move further from the ascending aorta?
Decrease in SBP
Increase in DBP
Narrowed pulse pressure
No change to MAP
(increase) in SBP
(decrease) in DBP
(wide) pulse pressure
No change to MAP
What is the A wave associated with in the CVP waveform?
Ventricular contraction
Passive atrial filling
Atrial contraction
ventricular emptying
Atrial contraction
What would cause a cannon A wave on a PAC tracing?
Mitral stenosis
Tricuspid stenosis
A-fib
Tricuspid regurgitation
Mitral regurgitation
Mitral stenosis
How many cm would you expect to insert a central line when using the RIJ?
10
15
20
25
15
A patient present with acute RV failure with a PAP of 62/25, HR 74, BP 88/40, CI 1.8. What combination of drugs would be a drug to treat this patient with?
Norepinephrine
Phenylephrine
vasopressin
Milrinone
Epinephrine
Vasopressin
Milrinone
During your preop assessment, you notice this on the ECG? The patient is scheduled for a AVR and the surgeon is asking for a PAC. What do you do?
No PAC, LBBB increases the chance of RBBB and CHB
During insertion of the PAC notice this on the ECG. What should you do?
Monitor closely as you continue to thread PAC
Withdraw PAC immediately
Ignore as it must be from the techs prepping the patient
Give lidocaine
monitor closely as you thread the PAC
