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126 Cards in this Set
- Front
- Back
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The heart lies behind the _____ and is bordered by what ribs?
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Behind the sternum, bordered by 2 and 6th ribs
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75% of blood from the left ventricle is drained by the _______. The remainder is drained by:
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75% coronary sinus, 25% from anterior cardiac and Thebesian veins
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Foramen Ovale is patent in what % of patients?
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20-30
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Formula for calculating EF
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(EDV-ESV)/EDV
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What is a "normal" stroke volume?
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70 ml (60-70% EF or 100-120 ml EDV)
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What causes the S1 sound?
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Closure of the AV valves
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What causes S2 sound?
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Closure of the pulmonic and aortic valves
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What causes S3 sound?
This can be normal in_______. |
Fluid overload ("slosh-ing-in")/mitral regurgitation
Can be normal in children and young adults |
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S4 is caused by
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"A stiff wall"- ventricular hypertrophy
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What are signs and symptoms of pericarditis? How is it treated?
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Chest pain, dyspnea, pericardial friction rub, ST-T wave changes (in up to 90% of patients); enlargement of heart shadow on CXR; treated with antibiotics and antiinflammatories
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Normal intrapericardial pressure is ______. Therefore, if cardiac tamponade occurs, your _____ decreases and your _______ increases
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0-2 (subatmospheric); tamponade causes decreased diastolic filling and increased SVR (d/t venous congestion)
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Pulsus paradoxus is a fall of ______% during _______
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ABP drops by >10% during inspiration
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Beck's Triad: what is it, and what condition does it relate to?
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Cardiac tamponade:
3Ds: Jugular venous DISTENTION DISTANT heart sounds DECREASED blood pressure (hypotension) |
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Equalization of pressures on PAC is diagnostic of:
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Cardiac tamponade
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The right ventricle is drained by:
The LV is drained by: Deep muscle of RA and RV is drained by: |
Anterior cardiac veins
Coronary sinus Thebesian veins |
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The branching of the LCA may make it more prone to occlusion because of whose law?
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Pouseille's law: branching creates turbulent flow
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Formula for coronary perfusion pressure:
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CPP= Aortic Diastolic BP - LVEDP
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What are the normal determinants of myocardial oxygen supply?
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1. HR (increased HR = decreased time for filling during diastole)
2. DBP-LVEDP 3. Arterial oxygen content (bound to hemoglobin!!!) 4. Diameter of coronary artery |
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What are the normal determinants of myocardial oxygen demand?
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1. HR
2.Wall tension 3. Myocardial contractility |
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Name 3 factors that will decrease myocardial oxygen delivery:
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1. Anemia
2. Decreased 2-3 DPG 3. Hypoxia |
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Name 5 factors that will decrease coronary blood flow:
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1. Tachycardia
2. Increased pre-load 3. Diastolic hypotension 4. Hypocapnia 5. Coronary spasms |
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Name 3 factors that increase myocardial oxygen demand:
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1. Tachycardia
2. Increased wall tension A. Increased pre-load B. Increased afterload 3. Increased contractility |
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What 2 factors both increase myocardial oxygen demand and decrease coronary blood flow?
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Increased HR
Increased preload |
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What happens during Phase 0 of the ventricular action potential?
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Rapid flow of Na ions into the cell through fast Na channels; membrane becomes les permeable to K ios; results in steep upstroke of graph; depolarization
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What happens during Phase 1 of the ventricular action potential?
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Cl enters and K ions leave the cell causing slight downward deflection of graph
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What happens during Phase 2 of the ventricular action potential?
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Plateau caused by activation of the slow Ca channels allowing Ca into cell,
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What happens during Phase 3 of the ventricular action potential?
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Large downward deflection of graph caused by movement of K out of the cell (repolarization); Ca channels are inactivated
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What happens during Phase 4 of the ventricular action potential?
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Resting membrane potential; concentration gradients are re-established
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Sympathetic nerves acting on the heart release _______. This causes ______(increased or decreased) inotropy, dromotropy, excitability, and chronotropy.
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Nerve endings release Norepinephrine causing inceased inotropy, chronotropy and dromotropy
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How does sympathetic stimulation of the heart bring about its effects?
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Decreases the resting membrane potential by making nodal cells more permeable to Na and Ca ions; makes ventricular calcum channels more permeable (causing inceased force of contraction)
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Where do the branches of the parasympathetic nervous system innervate the heart? How does it bring about its effects?
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Primarily innervates the SA and AV node; some innervation atria; Parasympathetic nerves release Ach, causing increased permeability to K ions, resulting in hyperpolarization (decreased excitability)
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A wave- what is happening in the heart?
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Atrial contraction (follows P wave on EKG); is responsible for atrial kick during ventricular diastole; peak of A wave represents maximal filling of LV and is RVEDP; should be measured at end expiration
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What are the lateral leads?
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I, AVL, V5, V6
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C wave- what is happening in the heart?
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Closure of AV valves during early systole; corresponds to S1 (closure of AV valves during systole) and represents the backpressure against the AV valves causing them to bow back into the atrium; occurs just following the QRS on EKG
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What are the inferior leads?
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II, III, AVF
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V wave:what is happening in the heart?
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V stands for Venous filling; represents atria passively filling with blood from vena cava during late systole; follows T-wave on EKG; coresponds with S2 (sound made by closure of the Semilunar valves)/
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What are the anterior leads?
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V3, V4
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X descent: what is happening in the heart?
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Atrial pressure declines during ventricular contraction; occurs mid-systole
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What are the septal leads?
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V1, V2
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Y descent: what is happening in the heart?
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Tricuspid valve opens and blood flows out of R. atrium into RV
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Which are the systolic events recorded on the CVP waveform and which are diastolic events?
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C,X, V occur during systole; A &Y occur during diastole
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Inferior MI: what CA is responsible?
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RCA
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What causes the dicrotic notch on A-line tracing?
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Transient increase in aortic pressure caused by closure of the Aortic valve
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What are possible S/S of RCA occlusion?
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SB, Sinus arrest, 1st and second degree heart block, PVCs
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Name 3 factors that inluence preload
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1. Filling time (inversely proportional to HR)
2. Filling pressure (atrial pressure) 3. Ventricular compliance |
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RCA infarction would cause ischemia in what portion of the heart?
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Inferior- seen in leads II, III, AVF
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A shift to the left on the Frank-Starling curve implies:
A shift to the right means: |
Left shift - improved ventricular function
Right shift: tendency towards cardiac failure |
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Posterior infarctions are caused by occlusion of what artery
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Most likely RCA
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Increased afterload causes increased ________ and ________.
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Systolic ventricular pressure and increased compression of subendocardial blood vessels
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An average adult's max cardiac outpuut is acheived at a HR of _____.
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120
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What parts of the heart does the LAD feed?
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Anterior Septum, Anterior wall LV, Bundle Branches
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Baroreceptors located in the ______ and _______ sense changes in ______ and cause and inversely proportional change in _____.
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Baroreceptors in cartid sinus and aortic arch are stretch receptors that dectect changes in blood pressure and cause inverse changes in HR (increased BP causes decrease in HR by increased PNS activity, decreased BP causes increase in SNS stimulation and causes increased HR)
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What parts of the heart does the L Circumflex Artery feed?
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Part of the LBBB, L. lateral wall, and the SA node in a minority of people (L. dominant)
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Describe the Bainbridge reflex
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Stretch receptors in the atria sense increased venous return (increased stretch) and send signals via CN X to the Vasomotor center in the Medulla causing decreased efferent CNX (Vagal) stimulation and SNS stimulation and increasing HR 10-15%
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What clinical symptoms would you expect with a LAD occlusion?
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BBB
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_______ is released by the heart in response to atrial stretch. It decreases blood volume by______
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Atrial Natiuretic Peptide (or Factor) causes increased Na (and indirectly water) excretion, and thereby reduces blood volume
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What clinical symptoms would you expect with occlusion of the RCA?
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Sick Sinus Syndrome, AV block, bradycardia
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The Renin-Angiotensin-Aldosterone system is stimulated by ______. It causes _______ and ________.
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Decreased blood flow to the kidneys. Causes vasoconstriction and Na and H20 retention
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In a junctional rhythm, the rate is set by
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The AV node
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ADH is released from the posterior pituitary in response to _____. What does it do? What receptors does it work on?
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Baroreceptor and osmoreceptor (Hypothalamus) stimulation, Angiotensin II release. It causes increased H20 reabsorption and increasing peripheral vascular resistance. It works on Vasopressin receptors (V1-V3).
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Intrinsic rate of AV Node
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40-60 bpm
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What does the RCA supply?
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-SA node (50-60% of people)
-Anterior RV -RA -AV node in 90% of people |
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A patient suffering from an occlusion of the RCA would be prone to _________
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Bradyarrhythmias (heart block)
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The LAD provides blood flow to:
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-Anterior 2/3 of interventricular septum
-Right and Left bundle branches -Anterior and posterior Papillary muscles of Mitral Valve -Anterolateral wall of LV -Apical wall of LV -Collateral flow to anterior RV |
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The Circumflex artery supplies blood to:
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-SA node in 40-50% of people
-Left Atrial wall -Posterolateral LV -Anterolateral papillary muscle of MV -AV node in 10% of people |
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What does dominance mean in terms of coronary circulation?
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Dominance is determined by which artery (RCA or Cx) feeds the posterior descending artery. If it is RCA, as in 50% of population, it is said to be "right dominant"
Cx is dominant in 10-15% of the population, and the remainder (35-40% of the population) is mixed |
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What does the PDA feed?
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The interventricular septum and inferior wall
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The heart requires most (65%) of its O2 demand during _______ to overcome _______. What drug can help decrease this?
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Systole; to overcome afterload; Milronone decreases afterload and therefore decreases myocardial O2 consumption
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What are the two most important leads in determining ischemia? (i.e. if you could only look at two leads, what would they be?)
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II, V5
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What is responsible for Phase 0 in nodal cells? In ventricular cells?
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Phase 0 (depolarization) is caused by calcium leak channels in nodal tissue (which results in automaticity). In ventricular cells, Phase 0 is caused by rapid Na influx.
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What is the resting membrane potential in ventricular cells? In nodal cells? In neurons?
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In neurons and skeletal muscle, the resting membrane potential voltage is about -70. In Ventricular cells, it is -90. In nodal cells it is -55-60
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What is the intrinsic rate of the SA node? The AV node? The Purkinje system?
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SA node 60-100
AV node 40-60 Purkinje (ventricular) 20-40 |
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Parasympathetic and Sympathetic stimulation affects what phase of the cardiac action potential?
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Phase 4- Sympathetic stimulation causes increased conductance of Potassium and more rapid repolarization, shortening the refractory period. PSNS stimulation causes decreased permeability to K ions and lengthens Phase 4, slowing the HR.
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What is the normal PR interval?
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0.12-0.2
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What leads will show a right bundle branch block?
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Remember WilliaM MarroW- A right bundle branch block will have an M shape in V1 and a W shape in V6
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Inverted T waves indicate ______.
ST elevation indicates _________. |
Inverted T waves indicates ischemia
ST elevation indicates infarction |
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What is concentric hypertrophy? What causes it?
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Muscle size increases but chamber diameter remains the same- caused by increased afterload (Hypertension, Aortic stenosis, coarcation of the Aorta)
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What law applies to the effect ventricular hypertrophy?
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Law of LaPlace: To compensate for increased left ventricular pressure, the wall thickens to reduce wall stress (T (wall stress) = Pressure x (radius/ thickness))
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What is the formula for CO? What factors determine stroke volume?
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CO= SV x HR
Stroke volume is effected by preload, afterload, and contractility |
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What is the average adult cardiac output?
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5 lpm
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Cardiac output equations are derived from whose law? What is the equation for determining CO according to this law?
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Ohm's Law:
CO = ((MAP-CVP)/SVR) x 80 |
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Name 6 causes of decreased Cardiac output
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1. Cardiac disease
2. Decreased pre-load 3. Increased afterload 4. Drugs 5. Dysrhythmias 6. Poor contractility |
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The oculocardiac reflex: afferent limb, efferent limb, and effects
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Afferent V to Efferent X; causes bradycardia, decreased SVR/BP, arryhthmias
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Traction or pressure on peritoneal structures (such as with placement of retractors) may cause _______ by means of the ________ reflex.
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May cause bradycardia, apnea, and hypotension due to stimulation of the celiac reflex
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What is the equation for MAP?
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MAP=(DBP +(SBP-DBP)/3)
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What is SVO2? In times of low CO, what happens to SVO2?
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SVO2 is a meausure of oxygen extraction by the tissues. In times of low cardiac output, SVO2 will be decreased as the body extracts more oxygen; normal SVO2 is .6-.75 and varies proportionately with Cardiac output and arterial oxygen content of blood (SpO2 and Hgb)
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What is a normal stroke volume?
CO? CVP: |
SV; 50-100 ml
CO: 4-8 lpm CVP: 0-6 |
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What is a normal PAP?
What is a normal PCWP? What is a normal SVR? What is a normal MAP? |
PAP: 25/10
PCWP: 8-12 SVR: 900-1300 MAP: 70-110 |
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What will cause an upward shift of the Frank-Starling curve? A downward shift?
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Up shift: Increased contractility, decreased afterload
Down shift: decreased contractility, increased afterload |
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What will cause a left shift on the Frank-Starling curve? A right shift?
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Left shift: decreased preload
Right shift: increased pre-load |
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What is the formula for EF?
How do you calculate it based on a normal pressure volume loop? |
(EDV-ESV)/EDV
Bottom Right point- Upper Left point /bottom right point |
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Eccentric hypertrophy: what is it and what is it caused by?
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Chamber dilates but does not gain muscle mass; caused by volume overload (mitral or aortic regurgitation)
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What ion is responsible for establishing the resting membrane potential in ventricular cells?
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Potassium
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When hypocalcemia is present, the plateau phase of the ventricular action potential is _______. This results in a ________ HR.
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Plateau phase is longer in hypocalcemia, causing decreased HR
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Explain sinus arrhythmia and its relationship to the Bainbridge reflex
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During inspiration, intrathoracic pressure decreases, causing increased venous return and stretching of the RA. This stretching stimulates the Bainbridge reflex and thereby increases HR
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The QT interval represents which phase of the ventricular action potential?
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Phase 2 (plateau)- the time between depolarization and repolarization
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What effect would alterations in calcium have on the QT interval?
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Hypocalcemia would result in a prolonged QT and hypercalcemia would result in a short QT
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The number one complication from AAA
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MI
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What are the presenting symptoms for AAA?
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Pulsatile mass; ruptured = hypotension and back pain
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What lines and fluids do you need prior to induction for AAA repair?
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Neo and Nitroglycerin both in line; large bore IV and ALine before induction
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In AAA repair, what will happen to your patient's blood pressure above and below the cross clamp?
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Hypertension above cross-clamp, hypotension below
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Juxtarenal and suprarenal aortic cross clamp is more likely to result in _________.
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ARF
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Infrarenal aortic cross clamp results in a _____% reduction in renal blood flow
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38%
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What are potential ischemic complications for abdominal aneurysm repair?
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renal failure, hepatic ischemia and coagulopathy, bowel infarction, and paraplegia
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Cardiovascular effects of aortic cross clamping are affected primarily by ________
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Level of cross clamp application
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The Artery of Adamkiewics takes off at the ______ level and supplies the ______ spinal cord.
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T8-L2 level; supplies anterior 2/3 spinal cord
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Injury to the Artery of Adamkiewics leads to Anterior Spinal Artery Syndrome. What are the tracts affected and what are the symptoms?
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Corticospinal tract disruption leads to para/quadraplegia (depending on level of injury) and disruption of the spinothalamic tracts results in loss of pain/temperature sensation at and below the injury, while touch, proprioception and vibration are preserved (carried in posterior column medial lemniscus tracts)
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What are three medications that might be used for renal protection before aortic cross clamp?
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Mannitol, Lasix, fenoldapam
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A spinal cord injury presenting as loss of movement, pain, and temperature with preserved touch, vibration and propriocention is caused by_______.
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Disruption of blood flow through the anterior spinal artery (Artery of Adamkiewics)
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Ischemic injury can be expected if aortic cross clamp time exceeds _____ minutes without protective measures.
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34 minutes
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What is the equation for spinal cord perfusion pressure?
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MAP-ICP
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What measures might be taken to protect the spinal cord if aortic cross clamp above the level of the Artery of Adamkiewics is planned?
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Lumbar drain, SSEP and MEP monitoring
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The most common placement of the aortic cross clamp is ________
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Infrarenal
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The law explaining why large aneurysms are more likely to rupture
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Law of LaPlace- Tension= pressure x radius; so at a constant blood pressure, an increased radius causes increased wall tension (and propensity toward rupture)
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_______ and S/P MI are at increased peri-operative risk. Highest risk continues for _____ after MI.
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CHF and <1 month post MI is greatest risk; risk continues for 6 months post MI
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The largest risk factor for intraop CV complication is ______. What are 2 others?
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Largest risk: emergency surgery and operative site (vascular surgery, intrathoracic, intraperitoneal, and aortic surgeries highest risk)
Other risks: sugery > 3 hours, tachycardia and labile hemodynamics |
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How long does it take collateral vascularization to occur?
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Begins in 24-48 hours following subacute occlusion and may reach normal flows in approx 1 month
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Intraoperative reinfaction carries a ______% mortality. This is best prevented by:
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50% mortality; prevent with close hemodynamic monitoring and aggressive treatment
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Does hx of PTCA/CABG inrease perioperative risk?
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No; revascularized so no increased risk
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Angina is caused by intracardiac release of _________.
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Adenosine caused by breakdown and of ATP during periods of ischemia and accumulation of adensosine as a byproduct
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What effects does adenosine have on the heart?
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Decreased conduction through AV node and decreased contractility by means of decreasing cAMP and resulting in hyperpolarizaton due to outward K ion movement.
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What percent of MI's occur without angina? What is a risk factor for this?
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10-15% are "silent"; risk factors include diabetetic neuropathy
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What is the difference between stable and unstable angina?
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Stable angina occurs with exertion and is relieved by rest/NTG; Unstable angina is new onset (<2 months), increased in severity, frequency (>3 x day), or duration, occurs at rest, or is unpredictable (no precipitating factors)
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What is the difference between primary fibribolysis and secondary fibrinolysis?
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Primary- normal break down of clots
Secondary- break down of clots d/t medications, medical disorder, etc. |
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What is cardiac pre-conditioning? What channels are opened and what do they do? What closes these channels?
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Protective, adaptive cardiac response to periods of subacute ischemia which protects against further damage should ischemia worsen; ischemia causes increased adenosine and potassium which opens channels that release NO (Morphine also opens these channels). Hyperglycemia closes these channels- correllates DIRECTLY with size of infarct
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What is a benefit of volatiles in CAD?
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Cardiac pre-conditioning
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