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95 Cards in this Set
- Front
- Back
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What pump is responsible for the cellular action potential? |
Sodium-Potassium Pump (Na-K pump) |
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When is the cell considered "irritable?" |
during the refractory/repolarization period |
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Which node is considered the "pacemaker?" |
SA Node |
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Which node slows the impulse through the heart? |
AV Node |
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What is the pathway of electrical flow through the heart? |
SA Node AV Node Bundle of His Purkinje Fibers |
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Which node is controlled by the autonomic nervous system? |
SA Node |
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Which part of the electrical impulse is the site of bundle branch blocks and intraventricular conduction delay? |
Bundle of His |
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Where do Purkinje fibers extend from and to? |
From apex of heart to aorta |
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On an ECG, what does the P-wave represent? |
atrial depolarization (contraction) |
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On an ECG, what does the PR interval represent? |
the time between atrial and ventricular contraction |
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On an ECG, what does QRS represent? |
Right and Left ventricular contraction |
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On an ECG, what does the T-wave represent? |
ventricular repolarization |
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How does the SNS increase HR and strength of cardiac contractions? |
-direct spinal innervation to myocardium from central medulla or -act on beta-1 receptors (catecholamines) |
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How does the PNS decrease HR and put on the brake? |
-peripheral baroreceptors from vagus nerve or -cholinergic receptors |
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What is the intrinsic SA Node rate? |
100 bpm |
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What is the intrinsic ventricular rate? |
40 bpm |
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What parts of the heart are supplied by the Right Coronary Artery (RCA)? |
-Right Atrium -SA Node -Right Ventricle |
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What parts of the heart are supplied by the Left (Main) Coronary Artery (LMA)? |
2 Branches: -Left Circumflex (Cx): supplies lateral left ventricle -Left Anterior Descending (LAD): supplies left ventricle and septum |
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Which part of the heart is considered the "Hand of God?" |
left ventricle |
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Ventricular contraction is termed: |
systole |
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Ventricular relaxation is termed: |
diastole |
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In terms of cycle time, what portion of the cycle is systole? and what portion is diastole? |
1/3 systole 2/3 diastole |
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What is cardiac output? |
amount of blood pumped through the heart in 1 minute |
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What 2 determinants affect cardiac output? |
1) stroke volume 2) heart rate |
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What is stroke volume? |
mL of blood pumped by the ventricles with EACH contraction |
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What affects stroke volume? |
preload & afterload |
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What is heart rate? |
number of ventricular beats per minute |
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What affects HR? |
-SNS (epinephrine) -fever -fluid status -exercise |
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What is the cardiac reserve? |
ability of the heart to increase cardiac output (CO) when O2 demand increases |
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What is preload? |
ventricular stretch |
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What is afterload? |
the pressure the ventricle must overcome to push blood forward |
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What is Starlings Law? |
ventricular stretch |
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What percentage of blood is stored in our veins? |
70% |
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In regards to systemic autoregulation, what is the tissue's response to acidosis, hypoxia, fever, and histamines? |
Vasodilation |
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In regards to systemic autoregulation, what is the tissue's response to catecholamines, angiotensin, and hypothermia? |
vasoconstriction |
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What is systolic blood pressure? |
pressure exerted during left ventricular contraction |
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What is diastolic blood pressures? |
pressure exerted during ventricular relaxation |
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What is pulse pressure? |
difference between systolic and diastolic pressures |
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What is the Blood Pressure equation? |
BP = cardiac output x peripheral vascular resistance |
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What does PVR stand for? |
peripheral vascular resistance |
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What are some variables affecting BP? |
-blood volume -viscosity -venous return -elasticity of arteries -rate -force of contractions |
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What is Peripheral vascular resistance? |
resistance to flow |
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What are some variables affecting PVR? |
-friction of vessel walls -vasoconstriction / vasodilation -blood viscosity -hormones (ADH, aldosterone) -SNS/catecholamines |
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What does beta-1 do? |
-increase HR -increase force of contraction -Increased cardiac output |
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What does alpha-1 do? |
-increase venous return/squeeze -vasoconstriction -increase PVR |
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Factors/disease states that contribute to Coronary Artery Disease (CAD): |
-HTN -Angina/MI -Arrhythmias -CHF -Congenital defects |
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Types of diagnostic evaluations for CAD: |
-ECG -Exercise stress test -CXR -Cardiac Catheterization -Doppler Studies -Echocardiogram -Blood tests |
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Why are diagnostic tests performed for CAD? |
to determine which vessels are affected |
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What does cardiac catheterization assess? |
plaque in the arteries |
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What kind of blood tests evaluate CAD? |
-troponin -CK-MB -myoglobin |
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What is arteriosclerosis? |
normal degenerative process in arteries -decreased wall elasticity -thickened, narrowed, inflexible walls |
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What is atherosclerosis? |
"lump or gruel" -formation of atheromas (lipid filled plaques) that cause narrowing |
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What are plaques usually made of? |
cholesterol/lipid core with cellular debris, fibrin, plt, thrombi |
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What type of heart disease ensues if blood supply cannot keep up with oxygen demand? |
ischemic heart disease |
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Which cholesterol is harmful when high? |
LDL |
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Which lipid is related to glucose metabolism? |
triglycerides |
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What are some non-modifiable risk factors for CAD? |
-age (>40) -gender (men>women) -genetics |
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What are some modifiable/controllable risk factors for CAD? |
-cholesterol levels -lifestyle/obesity -smoking -diabetes -HTN |
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Treatment for general CAD: |
-STOP SMOKING -lower cholesterol -control HTN -surgery |
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What is angina pectoris? |
chest pain oxygen demand exceeds supply (especially with activity)
-causes ischemia in heart tissue |
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3 types of angina: |
1) stable 2) variant 3) unstable |
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Causes of angina: |
-athero/arteriosclerosis -coronary vasospasms -myocardial hypertrophy -anemias -tachyarrhythmias -respiratory diseases -HTN |
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What is an MI? |
coronary ischemia that leads to tissue damage/necrosis |
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3 causes of MI: |
1) Thrombus 2) Vasospasm 3) Embolus |
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What factor contributes to the extent of the damage during an MI? |
the length of time the hypoxia occurs
Time Is Muscle! |
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Signs & Symptoms for MI: |
-sudden substernal pain (may radiate to left jaw/arm/shoulder) -"crushing" feeling -no relief with rest or NTG
-may effect cardiac output -tachycardia/hypotension may develop |
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Sequence/pathophysiology of an MI: |
ischemia ; inflammation ; necrosis ; scarring ; decrease cardiac output ; CHF |
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MI diagnostic tests: |
-ECG -STEMI or NonSTEMI -Labs: CK-MB, Troponin, electrolytes, CBC |
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What is the mortality rate within first year of MI? |
30-40% |
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What is the #1 complication with MIs? |
Arrhythmias |
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Other complications after an MI: |
-Cardiogenic Shock -CHF -Ventricular aneurysm -Thromboembolism |
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Treatment for MIs: |
"MONA" (morphine, oxygen, NTG, aspirin)
-antiarrhythmatics -vasodilators -Beta blockers -thrombolytics |
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Interventions post-MI: |
-pacemaker -angioplasty -CABG (Bypass) |
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What do arrhythmias do? |
reduce pumping efficiency -decreases cardiac output |
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What can cause an arrhythmia? |
-damage to conduction system -electrolyte imbalance -fever -hypoxia -stress -drug toxicity |
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Normal sinus rhythm rate: |
60-100 bpm |
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sinus bradycardia rate: |
Less than 60 bpm |
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sinus tachycardia rate: |
Greater than 100 bpm |
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Which wave is affected in sinus node abnormalities / Atrial conduction delays? |
P-wave |
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3 types of sinus node abnormalities / atrial conduction delays: |
1) premature atrial contractions 2) Atrial flutter 3) Atrial fibrillation |
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Why is there a risk for clots in A. Fib? |
stasis of blood in atria |
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What happens during an AV Block? |
P-R interval delays |
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3 types of AV Blocks: |
1) First degree 2) Second degree 3) Third degree |
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What is First Degree AV Block? |
a FIXED, prolonged P-R interval |
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What are the 2 types of Second Degree AV Block? |
-Mobitz Type I: "Wenchebach" -Mobitz Type II: Irregular sporadic P's (very close to 3rd degree AV Block) |
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What is Third Degree AV Block? |
COMPLETE heart block -no communication between atria & ventricles -no coordination between P-wave and QRS
*needs IMMEDIATE pacing |
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What happens during Bundle Branch Block/IVCD (interventricular conduction delay)? |
interference with conduction in one of the bundle branches -no change in cardiac output, but QRS is widened
(ventricles don't contract together) |
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What happens during Ventricular Tachycardia? |
Ventricular rate: 100-150 -no atrial coordination -beating on empty; no stroke volume |
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Is VT shockable? |
YES! If pulseless |
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What happens during Ventricular fibrillation? |
quivering of ventricles no coordination -ALWAYS pulseless |
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Is V. Fib shockable? |
YES! |
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Do Premature Ventricular Contractions (PVCs) affect cardiac output? |
no, but can lead to ischemia or V. Fib |
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What is cardiac arrest? |
asystole -no contractions |
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Is a flatlike ECG shockable? |
No |
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What can cause Cardiac Arrest? |
-drug toxicity -acidosis -myocardial ischemia -hypoxia -excessive vagal stimulation |
