Test 1 Flashcards
Aortic annulus is attracted to pulmonic annulus by
Tendon of conus
Aortic annulus also connected to AV valves by
Ventral fibrous body
What constitutes the fibrous cardiac skeleton
Four valve annuli
4 components of skeletal base of heart
Valve annuli
Aortic and pulmonary roots
Central fibrous body
Fibrous trigones
Location of coronary sinus
Between AV orifice and valve of IVC
Compare thickness of RV and LV
RV 4-5mm
LV 8-15mm
Compare upper 1/3 of septum to lower 2/3
Upper 1/3 is smooth endocardium
Lower 2/3 is trabeculae
Myocardium is ____ layers. Middle is _____
3
Middle is muscular which runs in spiral fashion
Normal size of aortic, tricuspid, and mitral valve
Aortic. 2.5-3.5 cm2
Mitral. 4-6 cm2
Tricuspid. 7 cm2
Coronary artery which typically provides flow to bundle branches
LAD
Provides flow to anterior 2/3 of IVS, bundle branches, papillary muscles of MV, anterior-lateral and apical LV
LAD
Provides flor to LA and posterior-lateral LV
Circumflex
Provides flow to SA/AV nodes
RCA
Provides flow to SA/AV nodes, RA, RV, posterior 1/3 of IVS
RCA
Dominance is determined by
Whether the circumflex of RCA provides flow to PDA
Effect of CAD of coronary vascular smooth muscle tone and anitcoagluation
Thickening of endothelium resulting in clot- vasospasm
Adversely effects autoregulatory fx of vascular endothelial cells expressing anticoagulant substances and myocardial blood flow
Define coronary perfusion pressure and its component/formula
CPP = DBP - LVEDP
Compare LV and RV perfusion in systole and diastole
RV fills throughout cycle
LV fills during diastole
Area of myocardium most affected by extravascular compression and higher LVEDP
Subendocardium
Lower heart rate minimizes compression
Key responses to CAD in coronary circulation
Collateral flow and remodeling
4 determinants of coronary blood flow
Perfusion pressure
Myocardial extravascular compression
Myocardial Metabolism
Neurohumoral control
Determinants of myocardial oxygen supply
Heart rate ** PCWP/LVEDP** DBP O2 sat Hct CAD
Components of myocardial oxygen demand
Heart rate **
PCWP/LVEDP **
SBP
CO
2 determinants of myocardial oxygen balance that both decrease supply and increase demand
Increased HR and PCWP/LVEDP
Increased SNS from what segments increase chronotropy and inotrope
T1-T4
Effect of increased PNS activation on chronotropy
SNS competes with PNS in medulla
PNS has only modest effect on inotropy 30%
Role of accessory pathways in dysrhythmia
Abnormal accessory pathways bw atria and ventricles may bypass the AV node and cause re-entrant dysrhythmias
Basic contractile unit of monocytes
Sarcomere
Effect of actin-myosin configuration on contractility based on frank starling law
If hypovolemia don’t have same wall tension and suboptimal interaction
Wall stress is typically greatest where
Subendocardium
Blood supply lowest and demand highest
normal size of aortic valve
> 2cm
2.5-3.5cm2
Normal mitral valve area
> 2cm
role of accessory pathways in dysrhythmias
Bypass AV node causing re-entrant dysrhythmias
LaPlace’s law. ______ and ______ vary directly with _________. Inversely with _____
Wall stress and MVO2 diaries directly with internal pressure.
Inversely with wall thickness
Wall stress is typically greatest in ______
Why
Subendocardium
Blood supply lowest due to LVEDP
Demand highest
Myocardial sarcomere are relatively permeable to _______ and impermeable to_____
Permeable to K+
Impermeable to Na and Ca
Phase 0 ion movment
Fast Na channels open
Then slow Ca channels
Phase 1 ion movement
K+ channels open
Phase 2 ion movement
Ca channels more open
Phase 3 ion movment
K+ channels open more
Phase 4 ion movement
RMP
SA node AP has no phase _____
1 and 2
Pint 1 on pressure volume loop
MV closes
Point 2 on pressure volume loop
AV valve opens
Point 3 on pressure volume loop
AV closes
Point 4 on pressure volume loop
MV opens
Increased preload effect on pressure volume loop
Shifts to right
Increased SV
EDPVR is directly related to
LV compliance
Effect of increased afterload on pressure volume loop
Narrow and taller
Lower SV and higher pressures
Higher EDV
ESPVR reduced
ESPVR related to
Myocardial contractility
ESPVR is heart rate sensitive index of
Contractility
Heart failure shifts LV volume loop
To right
Compensates for decreased contractility
Aortic stenosis effect on PV loop
Higher pressure for given volume
Taller
Diastolic heart failure PV loop changes
Flat frank starling curve
Ways body compensates for heart failure
Salt and water retention
Vasoconstriction
Sympathetic stimulation
CV effects of valsalva maneuver
Decreased HR, contractility, vasodilation
CV effects of baroreceptors reflex
Decreased HR, contractility, vasodilation
CV effects of Oculocardiac reflex
Bradycardia
asystole
dysrhythmia
hypotension
CV effects of celiac reflex
Bradycardia
Hypotension
Apnea
CV effects of Bainbridge reflex
Increased HR
Decreased BP
Decreased SVR
Diuretics
CV effects Cushing reflex
SNS = hypertension
CV effects Chemoreceptors reflex
Increased respiratory drive
Increased BP
Determinants of BP
Cardiac Output
- HR
- SV
SVR
CO components
HR
SV
Components of SVR
Tone X Viscosity
Effect of alpha 1 receptors
Vasoconstriction
Effect of alpha 2 receptors
Blocks output- vasodilation
Effect of beta1 receptors
Increase heart rate and contractility
Effect of beta 2 receptors
Vasodilates
Increases glyco neo genesis
Effect of Muscarinic receptors
Decrease heart rate
Activates salivary/sweat glands
Limited decreased vascular tone
Epinephrine activates which receptors
Alpha and beta
NE activates
Alpha 1, alpha 2, and beta 1 receptors
NO beta 2
Dopamine activates which receptors
Alpha 1, beta 1, and dopamine receptors
NO alpha 2 or beta 2
Only catecholamines that activates beta 2
Epi
Preganglionic release which NTS sympathetic pathway
Acetylcholine.
Postganglionic sympathetic fibers release
NE
Termination of NE due to
Reuptake, dilution by diffusion or metabolism by MAO
Dexmedetomidine receptor and hemodynamic effects
Alpha 2 agonist
Receptor for carvedilol and hemodynamic effects
Mixed alpha beta antagonist
Receptor and hemodynamic effects of NE
Nonselective alpha beta
Receptor and hemodynamic effects epi
Non selective alpha beta
More beta 1
Receptor and hemodynamics for labetalol
Mixed alpha beta antagonist
Esmolol receptor and hemodynamic effects
Beta 1 antagonist
Four mechanisms of adrenergic receptor activation
Binding
Promote NE release
Block NE reuptake
Inhibition of NE inactivation
Ex of catecholamines
Epi
NE
Isoproterenol
Dopamine
Dobutamine
Examples of non- catecholamines adrenergic agonists
Ephedrine-alpha and beta
Phenylephrine- alpha 1
Terbutaline- beta 2
Clinical uses of alpha 1 activation
Nasal decongestant
Hemostasis
Adjunct to LA
Mydriasis
Elevation of BP (neo, NE)
Adverse effects of alpha 1 activation
Hypertension
Necrosis (extravasation of IV)
Bradycardia
CV effects of beta 1 activation
Increased HR, contractility, automaticity, conduction through AV node
Renin release from JG cells
4 therapeutic applications of beta 1 activation
Initiate contraction in arrest
Increase contractility in failing heart
Increase CO in shock
Improve AV conduction when AVB present
Adverse effects of beta 1 activation
Tachycardia
Dysrhythmias
Increased MVO2 = angina
Beta 2 receptor activation
Bronchodilation
Tocolysis on uterus
Overall CV effects of PDE-3 inhibitors
Vasodilation
Increased organ perfusion
Decreased SVR
Decreased BP
Increased contractility, HR, SV, EF
Decreased preload and PCWP
Dopamine 1-5mcg/kg/min
Induces natures is
Binds with D1 receptor dilating renal and mesenteric blood vessels
Dopamine at 5-10 mcg/kg/min
Primarily beta1 with increase in contractility and HR
Dopamine at >10mcg/kg/min
Primarily alpha1
Uses of vasopressin
Potent vasoconstriction
Volume loss in DM
Bleeding esophageal varicose
Vasoplegia with CPB
Most anesthetics and surgical stimulation
Alter ANS, autonomic reflexes, vasomotor control by pons/medulla
Increased density or receptors
Up regulation
Chronic decrease in receptor stimulation
Decreased density of regulation
Down regulation
Result of chronic increase in receptor stimulation
Factors influencing hemodynamic response to induction agents
Premedication Dose Speed of administration CV disease and compensation EF Emotional state Baseline autonomic tone Home meds Influence of adjuvant drugs Age DM HTN
Variables affecting anesthesia induction drug dose selection
Weight Adjuvant anesthetics Elderly Trauma Poor heart function Timing
Hemodynamic effects of propofol
Decrease in BP ***
Decrease preload, contractility, afterload (CO, SV)
Vasodilator effect of propofol due to
Decrease in sympathetic outflow
Direct vasodilation
Hemodynamic effects of thiopental
Increase HR
Decrease CI, BP, LVEDP
Histamine release
Decrease sympathetic outflow
Decrease contractility
Hemodynamic effects of methohexital
Increase in HR
Decrease in BP, profound hypotension
Decreased sympathetic outflow
Hemodynamic effects of diazepam
Decreased BP but slow onset and easier to control
Decree in MVO2 and LVEDP
HR decrease w/ sleep
Combine with opiate = profound decrease in SVR
hemodynamic effects of midazolam
Decrease in BP (more than Valium)
Mild increase in HR (5-15%)
Hemodynamic effects of Etomidate
DRUG THAT CHANGES HEMODYNAMIC VARIABLES THE LEAST
Very useful with hypovolemic
Hemodynamic effects of Ketamine
Increase MVO2
Increase PVR and SVR
Benefits of using N2O
Hasten onset
Short duration
Decrease dosage of other volatiles
Indications for inhaled induction
Compromised airway
Children
Indwelling ETT, trach
Needle phobia
Dosage for cardiac anesthesia
Propofol
0.2-1.5mg/GI
Dosage for cardiac anesthesia
Thiopental
0.5-4mg/kg
Dosage for cardiac anesthesia
Etomidate
0.1-0.3mg/kg
Dosage for cardiac anesthesia
Fentanyl
3-25mcg/kg
Dosage for cardiac anesthesia
Sufentanil
0.5-2mcg/kg
Dosage for cardiac anesthesia
Remifentanil
0.1-0.75mcg/kg/min
Dosage for cardiac anesthesia
Cisatricurium
70-100mcg/kg
Dosage for cardiac anesthesia
Vecuronium
70-100 mcg/kg
Dosage for cardiac anesthesia
Pancuronium
70-100 mcg/kg
Dosage for cardiac anesthesia
Succinylcholine
1-2mg/kg
Effects associated with intubation after induction with etomidate
Increase HR 15%
CI 19%
SVR 4%
Effects associated with intubation after induction with propofol
Increase HR 15%
SV 9%
CI 18%
Effects associated with intubation after induction with midazolam
Increase HR 4%
SVR 5%
CI 9%
Primary mechanism responsible for the CV effects of volatile anesthetics
Reduce intracellular calcium concentration
Reduce influx through sarcolemma and release from SR
Relationship between dose of volatiles and BP
decrease in dose related fashion
Due to decreased SVR
Relationship between dose of volatiles and SVR
Decrease in dose dependent fashion
Iso most
Relationship between dose of volatiles and CI
Decreases due to vasodilation and preload reduction
HR increases and compensatory so CI sustained
Relationship between dose of volatiles and HR
Increased due to modulation of SA automaticity, modulation of baroreceptors reflex, SNS activation
Des most
Effect of N20 on MACBAR of sevo
2.2MAC
Effect of N20 on MACBAR of des
1.3 MAC
Addiction of 1.5-3mcg/kg fentanyl decreases MACBAR to
0.4MAC