Cardiac APEX Flashcards
Inotropy
Chronotrophy:
Dromotrophy
Lusitropy
Sodium-Potassium ATPase Function
Type of transport:
Whats in and out:
What med inhib?
restore resting membrane potential
Active transport:
3 Na+ out., 2 K+ in
**Digoxin= inhib Na/KATPase = positive inotropic
3 Phases of SA node action potential??
Ion movement in each?
Action potential pathway:
- Phase 4: spontaneous depolarization of Na+ influx and Ca+2 in T-type
- Phase 0 = depolarixation
- Phase 3= Repolarization K+
-SA node -Internodal tracts -AV Node
-Bundle of His Left and right bundle branches
-Purkinje fibers
SVR formula
MAP formula
PVR formula
POTASSIUM effect on RMP and TP
Hypokalemia
Hyperkalemia
Severe hyperkalemia
Clinical example??
What can you give for hyperkalemia dysrthymias?
Hypo-kalemia
*RMP become more NEGATIVE
*Decreases resting membrane potential
*Cell more resistant to depolarization
Hyper-kalemia
-RMP become more POSITIVE
-HYPERKALEMIA = decreases threshold potential
*Cell depolarize more easily
Severe hyperkalemia:
*Severe hyper-kalemia Inactivates Na+ channels (they arrest in their closed-inactive state)
K+ containing cardioplegia solution CABG -the heart in diastole
*High K+ concentration does not allow the cells to repolarize, which locks the sodium channel in their closed-inactive state
- Clinical correlation: Give IV calcium to reduce risk of dysrhythmias in pts with hyperkalemia
CALCIUM effect on RMP and TP
Hypocalcemia
Hyper-calcemia
When does cell depolarize easier with?
Clinical correlation?
Hypo-calcemia:
* TP becomes more negative
*Cell depolarizes more easily
Hyper-calemcia:
* TP becomes more positive
*Cell becomes more resistant to depolarization
- Clinical correlation: Give IV calcium to reduce risk of dysrhythmias in pts with hyperkalemia (it increases gap between RMP and TP)
- Phase 0= Depolarization
- Phase 1 = Initial repolarization
- Phase 2= Plateau Ca+2 influx
- Phase 3 = Repolarization
- Phase 4= Maintenance of transmembrane potential (K+ out/ Na+/K-ATP function)
^ Preload = ____
Decrease preload = ____
The Importance of Atrial kick and Ventricular Compliance:
Atrial kick = ____ of LVEDV/ CO
Conditions associated with reduced myocardial compliance include:
- Atrial contraction (atrial kick)/ “priming the pump” = contributes to 20-30% of the final LVEDV and, by extension, cardiac output.
- A fib = lost of Atrial kick Reduce Cardiac output
The non-compliant ventricle is stiff = more dependent on a wall-timed atrial kick
Conditions associated with reduced myocardial compliance include:
* Myocardial hypertrophy
* Fibrosis
* Aging
Factors that increase contractility?
Factors that decrease contractility?
Factors that decrease contractility?
SVR and PVR formula
What law to describe ventricular afterload??
What is the formula?
Determinants of HR
Firing rates of each???
SA Node/ Keith flack
AV Node Purkinje Fibers
Intrinsic firing rate (BPM)
SNS tone
PNS tone
*SA Node: 70-80 (faster in the denervated heart)
*AV Node Purkinje Fibers : 40-60
*Intrinsic firing rate (BPM): 15-40
SNS tone= Cardiac accelerator fibers (T1-T4)
* NE = increases HR by increasing Na+ and Ca+ conductance.
–> This increases the rate of spontaneous phase 4 depolarization.
PNS stimulation (Ach)= slows heart rate by increasing K+ conductance and hyperpolarizing the SA node.
Right vagus innervates ____
Left vagus innervates ____
- Right vagus innervates the SA node,
- Left vagus innervates AV node
Reference value for each:
Oxygen Carrying Capacity: CaO2
Oxygen Delivery: DO2
Oxygen Extraction Ratio: EO2
Oxygen Consumption (VO2)
Venous oxygen concentration:
CaO2 = (Hgb x SaO2 x 1.334) + (PaO2 x0.003)
* Reference value = 20 mL/dL
Oxygen Delivery: DO2
* How much O2 is carried in the blood and how fast it is being delivered to the tissues
* DO2 = CO x [(Hgb x SaO2 x 1.34) + (PaO2 x 0.003)] x 10
* Reference value= 1000mL/min
Oxygen Extraction Ratio: EO2
* How much O2 is extracted by the tissues
* Reference value for whole body = 25% (individual tissue beds will vary)
Oxygen Consumption (VO2)
* Tells us how many O2 is consumed by the tissues
* Reference value = 250 mL/min or 3.5 mL/kg/min
Venous oxygen concentration:
* Tells us how many O2 is carried in venous blood
* Reference value = 15mL/dL
^ temp = ___ blood viscosity
Decrease temp = ____ blood viscosity
Increased Hct = ____
Decrased Hct + ____
Reynolds number (Re) can be used to predict if flow will be laminar or turbulent.
* Re < 2000: ____
* Re >4000: _____
* Re=2000-4000: ____
Laminar flow-molecules: Parallel path
Turbulent flow—non-linear path and will create eddies
Transitional flow—laminar flow along the vessel walls with turbulent flow in the center
- Re < 2000 predicts that flow will be mostly laminar
- Re >4000 predicts that flow will be mostly turbulent
- Re=2000-4000 suggests transitional flow
Changing the radius is the best way to impact flow, because flow is directly proportional to the radius raised to the ___h power
Double radius = Flow increases ___fold
Tripling radius= flow increases ___ fold
Quadrupling radius+ Flow increases ___fold
4th power
- Double radius =Flow increases 16 fold
- Tripling radius = flow increases 81 fold
- Quadrupling radius =Flow increases 256 fold
Law of Laplace formula?
Wall stress is reduced by: (3)
- ___ Intraventricular pressure
-____ radius
-_____ Wall thickness
Wall stress is reduced by:
* Decreased intraventricular pressure
* Decreased radius
* Increased wall thickness
Wall stress= Intraventricular pressure x Radius Ventricular thickness
Ohm’s Law
Risk of Perioperative MI in the Patient with Previous MI:
General population =
MI if>6months=
MI if 3-6 months =
MI <3 months =
The highest risk of reinfarction is greatest within ____ days
General population = 0.3%
MI if>6months=6%
MI if 3-6 months = 15%
MI <3 months = 30%
30 days of an acute MI. for this reason, the ACC/AHA guidelines recommend a minimum of 4-6 weeks before considering elective surgery in a patient with a recent MI.
Risk Factors for Perioperative Cardiac Morbidity and Mortality for Non-Cardiac Surgery
- High risk surgery (see below)
- History of ischemic heart disease (unstable angina confers the greatest risk of perioperative MI)
- History of CHF
- History of cerebrovascular disease
- Diabetes mellitus
- Serum creatinine > 2 mg/dL
- Unstable angina is defined as angina at rest, new onset angina (<2 months) , increasing symptoms (intensity, frequency, duration), duration exceeds 30 min, and symptoms have become less responsive to medical therapy.
Risk Factors for Perioperative Cardiac Morbidity and Mortality for Non-Cardiac Surgery
High risk??
Intermediate risk??
Low Risk??
High (Risk > 5%)
* Emergency surgery (especially in the elderly)
* Open aortic surgery
* Peripheral vascular surgery
* Long surgical procedures with significant volume shifts and/or blood loss
Intermediate (Risk = 1-5%)
* Carotid endarterectomy
* Head and neck surgery
* Intrathoracic or intraperitoneal surgery
* Orthopedic surgery
* Prostate surgery
Low (Risk <1%)
* Endoscopic procedure
* Cataract surgery
* Superficial procedures
* Breast surgery
LV Pressure-volume loop
6 stages??
How do you calculate EF?
Stenosis = ___ Hypertrophy
Regurg = _____ Hypertrophy
Regurg is eccentric hypertrophy
What are the hemodynamic goals for Aortic stenosis
HR:
PL:
Contractility
SVR
PVR
What are the hemodynamic goals for Mitral stenosis
HR:
PL:
Contractility
SVR
PVR
Most common dysrthymia?
A fib
What are the hemodynamic goals for Aortic regurg
HR:
PL:
Contractility
SVR
PVR
What are the hemodynamic goals for Mitral regurg
HR:
PL:
Contractility
SVR
PVR
6 risk factors for perioperative cardiac mortality?
Cardiac low risk?
Cardiac high and intermediate risk???
Cardiac enzyme in suspected ischemic event?
CKMB
Trop 1
Trop T
Initial elevation?
Peak elevelation?
Return to baseline when?
How to treat intra op MI
How to increase O2 demand
How to decrease O2 demand
Causes of each? HR, BP, PAOP
Modified New york Association Functional Classification of Heart failure?
Class 1:
Class 2:
Class 3:
Class 4:
6 complications of HTN
Difference between primary and seconday HTN?
7 causes of seconday HTN?
Primary essentail = more common and no idenfiable cause (95%)
Patho of pericarditis
Patho of pericardial tamponade
Kussmaul’s sign
what 2 conditions occur with this condition?
Kussmal associated with pericarditis and pericardial tamponade
beck’s triad??
associated with? and 3 signs
Pulsus paradoxus?
Conditions associated with pulsus paradoxus?
constrictive pericarditis and pericardial tamponade
Drugs to USE for pericardial tamponade and pericardiocentesis
Drugs to avoid for pericardial tamponade and pericardiocentesis
How long should elective surgery be delayed for pt after PCI:
Angioplasty without stent:
Bare metal stent:
Drug eluting stent:
CABG:
Describe the Crawford classification system of aortic aneurysm
Descrube debakey and stanford classification of aortic aneurysm
How does preload changes, AL changes, and contractility affect the pressure volume loop??
^PL? decrease PL?
^AL? decrease AL?
^Contract? decrease contract?
What does each vessel perfuse??
LCA
LAD
Circumflex
RCA
PDA
Best view for TEE? Myocardial ischemia?
- )
2.)
Best view for diagnosing left ventricular ischemia is: Midpapillary muscle level in short-axis
Second best view: apical segment also in short-axis
At rest: coronary blood flow is: ____
% of CO: ___
Coronary blood flow formula:
Coronary perfusion pressure formula:
*At rest, myocardium consume oxygen at a rate: ______
extraction ratio of: ____
MOST IMPORTANT DETERMINANT of CO2 VESSESL DIAMETER????
- At rest: coronary blood flow is 225 mL/min (4-5% of cardiac output)
Coronary blood flow = coronary perfusion pressure/ coronary vascular resistance
- Coronary perfusion pressure = Aortic DBP- LVEDP
*At rest, myocardium consume oxygen at a rate 8-10 mL/min/100g with an extraction ratio of ~70%
LOCAL METABOLISM IS THE MOST IMPORTANT DETERMINANT of CO2 VESSESL DIAMETER*
- Hypocarbia = coronary vasoconstriction or vasodilation
- Hypocarbia = coronary vasoconstriction
Endocardial blood vessels of the myocardium
Effects of Calcium in vascular SM:
Increased Ca+2 causes ______
Reduced intracellular Ca+ 2 leads _______
increased Ca+2 causes: vasoconstriction
Reduced intracellular Ca+ 2 leads: vasodilation.
Infective endocarditits that needs antiobiotics and dont
Need antibiotic:
* Previous infective endocarditis
* Prosthetic heart valve
* Unrepaired cyanotic congenital heart disease
* Repaired congenital heart defect if repair <6 months old
* Repaired congenital heart disease with residual defects that have impaired endothelization at graft site
* Heart transplant with valvuloplasty
Dont:
* Unrepaired cardiac valve disease including mitral valve prolapse
* CABG
* Coronary stent placement
* GI endoscopic procedures without infection
* GU procedures without infection
* TEE without infection
* Dermatologic procedures without infection
