ITE Cardiology Flashcards
During Thoracic aortic aneurysm stenting, as a cardiac stent-graft begins to open, the ejection force of the heart can push the stent-graft and cause it to migrate distally. This is known as ________, and can be prevented by ___(3)___
the “windsock effect”
- Induced-hypotension (systolic 70-80 mmHg)
- Transient cardiac asystole (adenosine)
- Rapid ventricular pacing ( > 180 bpm will stop L ventricular ejection)
Adenosine should be cautiously used in pts with ____, because adenosine can cause _____.
asthma / upper respiratory disease
bronchoconstriction
______ is the preferred treatment for complete heart block.
____ mode > ____ mode if the pt is still undergoing a procedure with electrocautery present
Pacing
VOO > VVI
- VOO will pace the ventricles without sensing electrical interference
- Asynchronous pacing
Third degree heart block, or complete heart block, is an interruption in conduction of ______
the impulses from the atria to the ventricles
- SA node still continues to generate impulse
Pacemaker code meaning
I-IV
I: Chamber(s) paced
II: Chamber(s) sensed
III: Response to sensing
IV: Rate response
mneumonic: “PSR” (Pacer) - pace, sense, response
Pacemaker setting VOO
- Single chamber mode
Pacing in Ventricle, Sensing OFF, Response to sensing OFF - VOO will pace the ventricles without sensing electrical interference, and regardless of heart's intrinsic activity - Asynchronous pacing
Pacemaker setting VVI
- Single chamber mode
Pacing in ventricle,
Sensing in ventricle,
Response to sensing is to Inhibit
- Senses heart’s intrinsic activity and inhibiting pacing when unnecessary
Pacemaker setting AOO
- Single chamber mode
Pacing in Atria, Sensing OFF, Response to sensing OFF - will pace the atria without sensing electrical interference, and regardless of heart's intrinsic activity - Asynchronous pacing
Pacemaker setting AAI
- Single chamber mode
Pacing in Atria,
Sensing Atria,
Response to sensing is inhibit
- pacemaker will adapt to what the intrinsic atrial rate is doing
- pace when needed, and inhibit when not needed
Pacemaker setting DDD
- Dualchamber mode
- tracking mode
Pacing in Atrium + Ventricle,
Sensing Atrium + Ventricle,
Response to sensing is Inhibit or Trigger
- (Intrinsic P-wave and QRS can inhibit pacing)
- (Intrinsic P-wave or atrial pace can Trigger an AV delay)
- Pacemaker can truly adapt to what the heart is doing
- Pacemaker will mimic normal conduction as closely as possible
Pacemaker setting VDD
- Dualchamber mode
- tracking mode
Pacing in Ventricle,
Sensing Atrium + Ventricle,
Response to sensing is Inhibit or Trigger an AV delay, maintaining AV synchrony
- (Intrinsic QRS can inhibit ventricular pacing)
- (Intrinsic P-wave can Trigger an AV delay)
- No pacing in the atrium, but an intrinsic P-wave can trigger an AV delay, resulting in P-wave tracking and possibly maintaining AV synchrony
Pacemaker setting DDI
- Dualchamber mode
- nontracking mode
Pacing in Atrium + Ventricle,
Sensing Atrium + Ventricle,
Response to sensing is to Pace or Inhibit
- Like having an AAI and VVI pacemaker working together at same time, but independent of eachother
- Great for atrial tachyarrhythmias (not afib), and P wave tracking is great for AV synchrony
Pacemaker setting DOO
- Dualchamber mode
- nontracking mode
Pacing in Atrium + Ventricle,
Sensing is OFF
Response to sensing is OFF
- AV sequential pacing at lower rate limit regardless of hearts own intrinsic activity
- Useful when magnet is placed over pacemaker or during surgery
Lusitropy is defined as ______, and results in LV pressure (increase/decrease) and coronary perfusion pressure (Increase/decrease)
Myocardial relaxation.
decrease
Increase
(Positive/Negative) lusitropy occurs with diastolic dysfunction
Negative
*Lusitropy is defined as Myocardial relaxation.
Inodilator therapy results in an increase in (lusitropy/inotropy)
both
- ie. milrinone
*inotropy: anything that affects the strength of muscle contraction of the heart (can be positive/negative)
Positive lusitropy results in a (rightward/leftward) shift of the diastolic filling phase on the myocardia pressure-volume loop. Resulting in (increase/decrease) CPP, LVEDV, SV
rightward
Increased
The main goal of medical treatment in pts with aortic insufficiency (aka aortic regurgitation) is to ___ (3).
- Decrease afterload
- (allows for forward flow) - Augment contractility
- (more forward flow) - Avoid bradycardia
- (less time for regurgitation)
*Fast, Full (preload), Forward
The use of metoprolol and phenylephrine in pts with aortic insufficiency is (good/bad).
bad
- Metoprolol: increase time in diastole, allowing more time for regurgitant flow
- Phenylephrine: increases afterload, when you should really decrease it.
Following carotid endarterectomy, (hypertension/hypotension) is a more common predictor of adverse events
hypertension
- peak 2 hr post op
- stroke/death
Neurological dysfunction following carotid endarterectomy (CEA), is mostly d/t ____, and is prevented by ____
Thromboembolism
peri-procedure antiplatelet therapy
(On/Off)-pump coronary artery bypass is associated with greater incidence of hemodynamic instability during distal graft anastomosis
OFF
- d/t positioning of the heart (verticalization)
or
- ischemia related to ligation of a coronary artery
*no mortality difference
If a pt suffers refractory hemodynamic instability during Off-pump coronary artery bypass, you will need to ____
convert to full CPB
(Full median sternotomy / Minimally invasive direct CAB) usually requires a double lumen tube for lung isolation
Minimally invasive direct CAB
- performed thru smaller thoracotomy incision and require lung isolation
- DL tube allows for proper visualization w/in mediastinum
Benefits of Off-pump coronary artery bypass (5)
- decreased incidence of low cardiac output syndrome
- shorter length of ventilation
- Shorter hospital stay, cost, infection
- less stroke
- less blood transfusions
Major disadvantage of Off-pump coronary artery bypass
higher incidence of repeat revascularization
Essential hypertension
- explain stages of cardiac output
Initial stages: increase in cardiac output
->
Cardiac output normalizes
(systemic venous resistance increases)
How does Essential hypertension affect the body’s sympathetic tone?
Increase
- contributes to increased BP
- labile response to sympathetic agonists and vasodilators
According to the AHA, pts should be administered supplemental O2 if the RA is < __%
94%
Initial dose of aspirin during suspected MI: __ mg
162-325 mg PO
Nitroglycerin is contraindicated when pt has evidence of (right/left) sided MI
Right
- pts are very sensitive to decreases in cardiac preload
The addition of _____ to priming solutions used in CPB will improve urine output.
Mannitol
- direct diuretic action
(True/False) b/l carotid endarterectomy (CEA) may be associated with loss of normal ventilatory responses to acute hypoxemia
True
- carotid body denervation may occur
- Carotid SINUS is located in the _________, and is responsible for maintaining BP through the ________ reflex.
adventitia of the carotid bulb of the internal carotid artery
baroreceptor
The carotid BODIES are located at the ________, and are responsible for respiratory stimulation through the ________ reflex.
bifurcation of the common carotid artery
chemoreceptor
Chemosensitive cells are located in the ______, and respond to changes in ______ by stimulating respiratory centers, increasing ventilatory drive
carotid bodies
pH status and blood oxygen tension
- (makes sense, both carotid bodies and chemosensitive cells stimulate respiratory/ventilatory response)
Type III protamine reaction
Tx?
Catastrophic Pulmonary HTN
RV failure mediated by heparin-protamine complexes and thromboxane A2
Tx: Inhaled NO, IV heparin, milrinone
- NOT mediated by histamine, and diphenhydramine not useful
Type I protamine reaction
Tx?
rapid infusion of protamine -> decrease in SVR -> direct histamine or NO release
- Myocardial depression not seen
- Inc PVR not seen
Tx: volume
Type II protamine reaction
IgE mediated anaphylaxis/anaphylactoid rxn
- hypotension
- rash
- vasodilation
- bronchoconstriction
Hyperthyroidism increases __ adrenoceptor density on the surface of cardiac myocytes
B1 and B2
- positive inotropic, chronotropic, and dromotropic effects
- hyperadrenergic state
*dromotropic = affects electrical impulse conduction
Chronic CHF causes B adrenoreceptors to (increase/decrease) on cardiac myocytes
Decrease
- prolonged activation of SNS -> downregulartion -> decrease contractile ability to respond to sympathetic stimulation
The main goal of CPB is to _______. The CPB circuit will drain deoxygenated blood from the R side of the heart, oxygenate the blood and return blood distal to where the surgeon is working on the aorta.
allow a surgeon to operate on a quiet, non beating heart while oxygenation and circulation are supported
Main components of full Cardiopulmonary bypass circuit (7)
- Venous limb
- Cardiotomy filter and venous reservoir
- Pump
- Oxygenator
- Heat exchanger
- Arterial limb
- Cardioplegia delivery system
Main goal of treating mitral regurgitation
- increasing HR
- Reduce systolic time - Reduce afterload
- Maintain NSR and normovolemia
- in early stages of MR: compensatory mech can reduce afterload, and increase LV compliance
- in severe stages: reduced EF, increased LV pressures/regurgitant vol
What blood produce is approved for AT III deficiency?
Fresh frozen plasma
- has AT III present (2-3 units)
- Correction of Antithrombin levels allows heparin to exert its full antithrombotic effect
ACT goal for CPB
400 - 480
most frequent side effects of amiodarone
bradycardia hypotension AV node block Prolong QT Hyperthyroid storm
Bivalruding is a ______ that exerts its clinical action by binding thrombin at 2 specific sites: ____ and _____
short acting direct thrombin inhibitor
- half-life 25 min
- can go stagnant in CPB circuit
fibrinogen recognition site
active catalytic site
_________ is the gold standard anticoagulant used during CPB
unfractionated heparin
- reversed with protamine
What is HIT?
Formation of IgG antibodies to heparin-platelet factor 4 complex that forms on the surface of platelets –> hyperaggregability of platelets
FDA approved alternatives to heparin
Hiruden and Argatroban
- bind active site of thrombin irreversibly
However, bivalrudin can be used in place of heparin for CPB
What is the best way to monitor oxygenation status in a pt with an LVAD?
Cerebral oximeter
- LVADS eject blood in a non-pulsatile manner
- Cerebral oximeters do not rely on pulsatile flow and can detect rapid changes in oxygenation
Stroke
- Fibrinolysis should be performed within ____ of arrival and ____ of symptom onset
- CT should be done within ____ of arrival
60 min
3 hours
25 min
At any given time __% of the patients blood is extracorporeal when CPB is being utilized and cause hypothermia
20-35%
- need heat exchanger and oxygenator
Two types of arterial pumps that draws blood from the venous reservoir and propels it into the oxygenator
- Roller pump
2. Centrifugal pump
During CPB, ______ pumps occludes a portion of the tubing and rolling the point of the occlusive contact along the length of the tubing itself –> forces blood forward in front of the point of occlusion while drawing blood in behind the occlusion point
Roller pumps
During CPB, ______ pumps are non-occlusive pumps and use spinning fins or channels on the inside of a cone to force blood forward
centrifugal pumps
- less traumatic than roller pumps
- less likely to generate air emboli
Intraaortic baloon pumps (IABPs) increase cardiac output by ___%. Balloon inflates during the beginning of diastole, and deflates right when ventricle is about to eject blood (end of diastole)
25%
- useful in cardiogenic shock
- Increase CO, MAP, EG, coronary blood flow
Intraaortic balloon pumps will cause the (systolic/diastolic pressure) to be higher in an assisted beat
diastolic pressure
- greatly augmented d/t inflation of the balloon
On EKG, Lead II is used to detect ______ ischemia and cardiac arrhythmias
R coronary artery
- Inferior leads
On EKG, Lead V3, V4 is used to detect ______ ischemia
L anterior descending (LAD) coronary artery
- Anterior leads
*LAD artery supplies apex of LV and anterior 2/3 of interventricular septum
On EKG, Lead II, III, aVF is used to detect ______ ischemia
R coronary artery:
- R atrium
- R ventricle
- Inferior aspect of L ventricle
- SA and AV node
On EKG, Lead I, aVL, V5, V6 is used to detect ______ ischemia
L Circumflex coronary artery or diagonal
- Lateral leads (supplies lateral wall of L ventricle)
On EKG, Lead V1, V2 is used to detect ______ ischemia
LAD
- Septal leads
Contraindications to intraaortic balloon pump (3)
- Mod-severe AI
- Aortic disease (dissection)
- Severe peripheral vascular disease
indications to intraaortic balloon pump (5)
- cardiogenic shock
- failure to wean form CPB
- severe MR
- augmentation during PCI
- bridge to transplant or VAD placement
The gas typically used during inflation of the IABP is typically ____
helium
- inert gas with laminar flow, which passes readily into and out of balloon
The IABP helium balloon should remain inflated during which part of the cardiac cycle?
Early diastole to late diastole
______ is the most common method to determine cardiac output. Ice cold injectate is inserted into CVP port of PA catheter and travels towards thermistor.
Thermodilution
In thermodilution, any technical error resulting in LESS of a temp change during CO measurement results in (overestimation/underestimation) of CO
Overestimation
- Assume blood is warming up faster than it actually is if programmed for ice cold water
In thermodilution, a R-to-L intracardiac shunt results in (overestimation/underestimation) of CO
False overestimation
- shunt will divert injectate away from thermistor
ACC/AHA guidelines state that pts undergoing PCI for stable ischemic heart disease should receive what medications and for how long after Bare Metal Stents and Drug Eluting Stents?
BMS: dual antiplatelet therapy for at least 1 mo after
DES: dual antiplatelet therapy for at least 6 mo after (or 3 mo in pts at high risk of severe bleeding)
Metoprolol is contraindicated in acute heart failure d/t ____
its negative inotropic effects
- B1 adrenergic receptor antagonist
- improves diastolic LV filling time
Diuretics improve symptoms of CHF by ______
reducing cardiac filling pressures along same frank-starling ventricular function curve
Administering muscle relaxants in a pt with an anterior mediastinal mass poses significant risk for airway collapse d/t _____
paralysis of skeletal muscles that were previously maintaining airway patency
Why doesn’t central venous pressure decrease with aortic cross-clamping?
With the increase in catecholamine levels, there is increased venoconstriction distal to the clamp driving central venous pressure higher
“Holliday heart syndrome” aka alcohol-induced cardiomyopathy (systolic HF) shows a ______ shift in the Frank-Starling curve
Downward shift
- poor contractile fxn
(Graph is SV vs LVEDP)
Epinephrine, a positive inotropic agent, will shift in the Frank-Starling curve _____
upward
Mitral stenosis murmur
low pitched mid diastolic rumble
- best heard at maximum impulse during exhalation
Mitral stenosis is most commonly d/t _____
a sequela of rheumatic fever
Diastolic murmurs
mitral stenosis
and
aortic regurgitation
Systolic murmurs
MR. Ass
Mitral regurgitation
Aortic stenosis
During CPB, optimal hemodynamic goals include:
- Pump blood flow:
- Arterial blood pressure of:
- Oxygen Sat in the venous cannula of:
- Pump blood flow: 1.6 - 3 L/min/m2
- Arterial blood pressure of:50-90 mmHg
- Oxygen Sat in the venous cannula of: > 65%
If a pt with a ventricular assist device suffers cardiac arrest, chest compressions should be started if MAPs are < ____mmHg
50 mmHg, bc the VAD is not providing adequate forward flow
Common reversible causes of cardiac arrest
5 H’s
Hypovolemia Hypoxia Hydrogen ions (acidosis) Hypo/hyperkalemia Hypothermia
5 T's Toxins Tamonpade Tension pneumo Thrombosis-heart Thrombosis-lung
Function of ventricular assists devices are based on what 3 main principles?
- Preload (hypovolemia)
- Rotational speed (RPM) (setting)
- Afterload (SVR/PVR)
- extremely sensitive to changes to all.
In pts with an ongoing intracranial hemorrhage, target SPB should be?
< 140 mmHg to minimize ongoing bleeding w/o compromising blood flow
In pts with an ongoing ischemic stroke, target SPB should be?
140-150 mmHg
- U shaped association, above and blow = worse outcomes
What is the “inverse-steal” or “robin-hood phenomenon?”
Opposite of cerebral steal
Preferential shunting:
- INTERVENTIONS that cause normal cerebral vasculature to preferentially vasoconstrict, while impaired areas of the brain will vasodilate.
- Take advantage with hyperventilation (hypocapnea)
What is “intracerebral steal phenomenon”?
When an intervention causes the normal cerebral vasculature to dilate in the setting of a focal obstructive lesion.
- vasculature around and downstream the lesion will maximally dilate in effort to preserve flow.
- steals blood from impaired areas of brain and worsening ischemia
What is a Maze procedure? (3)
- incision made into both atria
- endothelium of pulmonary veins is isolated from the atrial myocardium
- L atrial appendage ligation
- CPB is required
The LV is perfused during ______ and the RV is perfused during ____
diastole only
throughout the coronary cycle
In CPB, the _____ acts as a substitute for the pts lungs, while the _____ acts as a substitute for the pts heart
Oxygenator
Arterial pump
ACC/AHA guidelines for heart failure staging
- Stage A
- Stage B
- Stage C
- Stage D
- Stage A: High risk for HF
- Stage B: Asymptomatic HF
- Stage C: Symptomatic HF
- Stage D: Refractory ESHF
NYHA classification for heart failure
- Class I
- Class II
- Class III
- Class IV
- Class I: Physical activity not limited by HF
- Class II: Physical activity somewhat not limited by HF
- Class III: Exercise is limited by dyspnea during modest exertion
- Class IV: Dyspnea at rest or with minimal exertion
What is the primary MOA of epinephrine that is desired in cardiac arrest?
Alpha-1 agonism
- contraction of vascular sm -> vasoconstriction -> inc BP -> restore coronary perfusion
Why is alpha 2 agonism undesirable in cardiac arrest?
Sympatholytic effect
- reduce central and peripheral sympathetic outflow -> hypotension and bradycardia
Why is beta 1 agonism undesirable in cardiac arrest?
Inc cardiac contractility and inotropy ->
increase myocardial oxygen demand
Why is beta 2 agonism undesirable in cardiac arrest?
systemic vasodilation -> hypotension ->
decrease myocardial perfusion
An increase in systemic blood pressure results in a decrease in systemic vascular resistance through __________
carotid sinus baroreceptors
- located at bifurcation of INTERNAL and EXTERNAL carotids
- elevated BP -> causes stretching of arterial wall -> baroreceptors expand ->
increase parasympathetic output
Which is more sensitive, carotid baroreceptors or aortic arch baroreceptors?
Carotid baroreceptors
The carotid chemoreceptors and carotid baroreceptors are both innervated by ____
the sinus nerve of hering
- branch of glossopharyngeal n. (IX CN)
Biventricular pacing can be used for cardiac resynchronization in pts with NYHA class ___ or
Heart failure symptoms with an EF of ___,
and QRS of ___
to prevent sudden cardiac death.
- Class III: Exercise is limited by dyspnea during modest exertion
or - Class IV: Dyspnea at rest or with minimal exertion
EF: < 35%
QRS > 120 ms
Placing a magnet over an ICD will ______
suspect arrhythmia detection but will leave intrinsic pacemaker function intact
(True/False) LVADs are just as good as cardiac transplantation
true - at one year
- and complications are typically not life-threatening
Status 1 (most urgent) need for cardiac transplant (3)
- VA ECMO < 7 days
- Non-dischargeable BiVAD
- Mechanical Cardiac Support Device (MCSD) with ongoing life threatening ventricular arrythmia
- Will die without transplant
Status 2 pts (second most urgent) need for cardiac transplant (4)
- RVAD, Total artificial heart, or VAD in pts with single ventricle physiology
- Non-dischargeable implanted LVAD (complicated)
- Mechanical Cardiac Support Device (MCSD) < 14 days
- Intermitted Vtach or V fib
- Unable to be discharged from hospital w/ current lvl of circulatory support they require
Most common indication for retrograde cardioplegia is ____
aortic valve insufficiency
The cardioplegia solution is _________
a cold, potassium rich solution that decreases myocardial oxygen consumption by 97%
- anterograde flow stops at coronary restriction and doesn’t cover all of the myocardium, and risk ischemia
- retrograde flow can cover the other side
Minimally invasive mitral valve repair would require one- lung ventilation of (Right/Left) lung
Left lung ventilation
- R lung is deflated via either bronchial blocker or DL ET
In 85%of pts, the atrioventricular nodal branch of the coronary arterial system is supplied by the _____, which is represented in the EKG leads ______
RCA (R dominant coronary circulation)
II, III, aVF
- inferior leads
On EKG, Lead aVR is used to detect ______ ischemia
R ventricular outflow tract
What three drugs are utilized when considering antifibrinolytic therapies for CPB?
- Aminocaproic acid (ACA)
- Tranexamic acid (TXA)
- Protease inhibitor aprotinin
- used to inhibit activation of plasminogen to plasmin
Are antifibrinolytic therapies for CPB associated with improved mortality?
No.
- It decreases bleeding and blood product transfusions
(MEPs/SSEPs) are the best for detecting spinal cord ischemia in aortic surgery
MEPs
Spinal cord perfusion equation
SCPP = MAP - ICP
*by using spinal drain to remove CSF and lowering ICP, spinal cord perfusion increases
In aortic stenosis, why do pts benefit from higher SVR and low HR?
Slow HR allows for longer diastolic filling times ->
adequate filling/perfusion in thickened LV
Higher SVR (counter intuitive), but stenotic aortic valve provides much greater resistance to LV outflow than any physiologic SVR that can be generated. - Inc in SVR -> only increases coronary perfusion
In aortic insufficiency and mitral regurgitation, why do pts benefit from lower SVR and higher HR?
Low SVR and Higher HR: less time in diastole -> promote forward flow out of LV outflow tract instead of back through regurgitant LV
In mitral stenosis, why do pts benefit from lower HR and lower PVR (pulmonary vascular resistance)?
Slow HR allows for longer diastolic filling times ->
(support RV and ensure adequate LV preload)
Most pts with clinically sig MS, have pulmonary HTN. Need Low PVR (support RV and ensure adequate LV preload)
Pt has QT prolongation, what is the treatment?
IV magnesium
What is considered prolonged QT?
440-470 ms
Cardiac resynchronization therapy (CRT) is indicated if ALL of the following are present: (5)
- Sinus rhythm
- EF < 35%
- NYHA class II-IV
- QRS > 150
- LBBB
Aortic valve closure occurs ____ wave on CVP, and ____ wave on ECG
just before the v-wave
just after the T-wave
Mitral valve closure occurs ____ on CVP, and ____ on ECG
after the a-wave
during the QRS complex
Mitral valve opening ____ on CVP, and ____ on ECG
occurs after the v wave
after the T-wave
Aortic valve opening occurs ____ wave on CVP, and just after the ____ wave on ECG
after the c-wave
QRS complex
An S4 sound is heard during _____, and is caused by the ____. It is generally seen with diastolic dysfunction and LVH
atrial contraction
vibration of the ventricular wall during this phase
Second most common EKG change
Prolonged QRS complex
Why does hyperkalemia result in prolonged PR intervals and widened QRS complexes?
Potassium is critical in maintaining precise cardiac myocyte resting potential
Hyperkalemia will depress conduction of electrical signals btwn myocytes
- *but initially accelerates repolarization - peaked t waves
