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108 Cards in this Set
- Front
- Back
What are two types of cardiac cells
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Electrical (pacemaker) and Mechanical (myocytes)
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Spontaneous generation of action potentials in pacemaker cells is called
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Automaticity
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Action potential in pacemaker cells are associated with opening of what ion channel
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Slow calcium
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What are 4 cardiac cell characteristics
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Conductivity, Contractility, Automaticity, Excitability
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What is Absolute Refractory Period (ARP)
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Cardiac cells can not conduct an electrical impulse (falls from beginning of QRS to midway of T wave)
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What is Relative Refractory Period (RRP)
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Cardiac cells have repolarized to threshold and can be depolarized in stimulus strong enough (falls from midway of T wave to end of T wave)
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What is the basis of automaticity
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Pacemaker cells are leaky to sodium at rest
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How does NE and E from the SNS effect depolarization
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They open the Na+/Ca++ channels leading to faster depolarization
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How does acetylcholine from the PNS effect depolarization
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Ach binds to muscarinic receptors which opens K+ channels slowing deplorization
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The cardiac control center is located in what part of the brain
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Medulla
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Where are the baroreceptors located
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Aorta and internal carotid arteries
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What nerve conducts PNS activity
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Vagus
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What is the mechanism of most abnormal electrical impulse formation
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Reentry
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Name the 4 layers of a vessel from the inside out
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Endothelium, Intima, Media, Aventitia
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What extrinsic mechanism is involved in blood flow control
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NE from the ANS causes vasoconstriction
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What intrinsic mechanisms control blood flow
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Autoregulation by brain, heart and kidney (monitor pressure and perfusion). Kidneys die at pressure greater than 80mmHg. Also have myogenic and metabolic hypothesis that adapt to pressure changes.
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Vascular smooth muscle is very dependent on what extracellular mineral
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Calcium
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What situations may lead to thrombus development in the veins
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Inactivity, IV catheter (if long term requirement-use subclavian)
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Give an example of a heart condition that may lead to thrombus development
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A-fib
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Name some causes of blood vessel obstruction
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Thrombus, emoblus, vasospasm, inflammation, mechanical compression
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What causes the pain of a migraine headache
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Dilation of cerebral vessels after a vasospasm leads to pounding headache
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What is Monckeberg Sclerosis
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Calcification in sclerotic area
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What causes Arteriolar sclerosis
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HTN - ususally seen in small vessels of eyes
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List some modifiable risk factors for atherosclerosis
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Smoking, HTN, glucose intolerance (dibetics have higher levels of fatty acids)
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List some non-modifiable risk factors for atherosclerosis
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Genetics, ethnicity and gender
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What is the impact of thromboangitits obliterans
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Inflammation that leads to decreased blood flow mainly seen in men
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What triggers Raynold Syndrome
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Cold or vibration or stress. Hands and fingers turn blue to white to red. Cause is unknown and mainly see in women
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What is the difference between a true and false aneurysm
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True-all three layers of vessel involved. False - one of the layers not effected (usually see in trauma or poor insertion of a tube)
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What is the difference between a saccular and fusiform aneurysm
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Saccular-weakness on one side of vessel. Fusiform-weakness on both side of vessel (Berry aneurysm)
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What causes an aneurysm
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Atherosclerosis and/or congenital weakness
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What should you document in an acute arterial occlussion
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Check and document upper and lower pulses and neurovascular (motor and sensory) function
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What are some characteristics of acute arterial insufficiency
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Pain, Pallor, Pulseless, Paralysis, Paresis, Poikilothermy
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What are some signs of chronic arterial insufficiency
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Intermittent claudication, atrophy of hair and skin, nails thicken
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Name some causes of valvular incompetency
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Obesity -vericose veins, Pregnancy (pressure on IVC plus progestins) cause leg swelling - should lay on left side also elevate legs
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What veins are commonly affected in chronic venous incompetency
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Deep veins (Femoral veins). Venous pressure over time equals arteriole pressure leading to stasis of blood. Skin turns black due to iron deposits
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Describe the process leading to venous insufficiency
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Ostruction of venous drainage leads to increased hydrostatic pressure causing edema and stasis
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Describe the formation of PE
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Venous stasis leads to thrombus formation, thrombus dislodges and occludes part of pulmonary circulation (hypoxic vasoconstriction, pulmonary edema and atelectasis) causing symtpoms (tachypnea, chest pain, dyspnea)
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How are the lymphatics involved in blood volume control
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They return 25-50% of blood proteins which maintain appropriate hydrostatic pressure. Without the proteins ascites and edema develop
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What conditions promote lymphedema
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Removal of lymph nodes (example radical mastectomy) arms swell up and alter blood flow breaking down the skin tissue in area
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What is the difference between primary and secondary lymphedema
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Primary is congenital (born without lymphatics or blocked thoracic duct). Secondary involves surgery
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What are some risk factors for HTN
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Age, Race, Sodium intake, Obesity
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When should you think secondary causes of HTN
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If person is under 20 or over 60
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Name some potential causes of primary HTN
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Excessive SNS, excessive RAS and insulin, too little naturietic peptide, insufficient dilators or excessive constrictors
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List different forms of shock that can cause hypotension
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Cardiogenic-pump failure, Anaphylactic-histamine dilation, Septic shock - endotoxins cause vasodilation, Distributive
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What four factors determine cardiac oxygen consumption
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Heart rate, contractility, afterload, wall tension
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What causes stable angina and how is it treated
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Increased workload due to stenotic vessel causes pain. Relieved by rest and NTG
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What causes Prinzmetal (Variant) angina and how is it treated
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Vasospasm of vessel unrelated to exertion or stress. Relieve via CCB and Long acting NTG
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What happens in unstable angina
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Plague rupture leads to partial occlussion of vessel. Clot dissolved before damage can occur
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What happens in an MI
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Plague rupture leads to complete occlussion of vessel causing myocardial cell death
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Describe the pathogenesis of acute coronary syndrome
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Plague ruptures exposing tissue thromboplastin which causes platelet aggregation and clotting cascade leading to thrombus development and eventually ischemia
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What are typical EKG signs of ischemia
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T wave peaking, flattening, inversion; ST segment elevation or depression; Large Q-waves
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What is the difference between a transmurial infarct and a non-Qwave infarct
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Transmurial - the entire thickness of the ventricular wall is effected. Non-Qwave - effects inner third to half on the ventricular wall
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What factors effect cardiac output
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HR, Preload, Afterload, Contractility
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What nerves does the baroreceptors use to feedback to the CNS info. about HR
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Cranial nerves IX and X
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What 3 things are needed for proper contracility of the heart
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Contracile proteins, ATP and free Ca++ ions in cytoplasm
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How might afterload be increased
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Aortic stenosis, systemic HTN
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Describe the compensatory responses to decreased Cardiac Output
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Immediate=increased SNS activity via baroreceptors, Followed by Renin system and Later by LV hypertrophy
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Define heart failure
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Inability to effectively pump the blood delivered to the heart
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What is the difference in systolic dysfunction and diastolic dysfunction in HF
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Systolic - (2/3 of people) - poor EF (<40%) often seen with MI. Diastolic (1/3 people) normal EF but poor relaxation often seen with old age
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What causes left sided heart failure
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Increased afterload (HTN, aortic stenosis); Impaired contractility (MI, ischemia, mitral regurg, aortic regurg);Obstruction of LV filling (mitral stenosis, tamponade); Impaired relaxation (LV hypertrophy, HOCM, Restrictive cardiomyopathy)
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What are the backward and forward effects of left heart failure
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Backward - Pulmonary congestion (dyspnea, orthopnea, cough, crackles, cyanosis) and Forward - poor cardiac output (fatigue, oliguria, confusion, restlessness, increased HR, faint pulses)
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What are the causes of right heart failure
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Left heart failure, lung disease, pulmonary HTN, PE, Pulmonic valve stenosis, RV infarct.
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What are the backward and forward effects of right heart failure
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Backward-Enlarged liver and spleen, ascites, anorexia, edema, JVD and Forward (fatigue, restlessness, oliguria, increased HR, confusion)
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What happens during ventricular remodeling in an MI
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LV thickens, wall stress increases aneurysm potential, healthy tissue becomes overworked and damaged
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What happens during ventricular remodeling of CHF
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Angiotensin II activates growth pathways to increase ventricular size to accommodate increased volumes--leads to further complications
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What are the common valve disorders
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Mitral stenosis, Mitral regurg., Aortic stenosis, Aortic regurg.
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What are the signs and symptoms of mitral stenosis
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Increased left atrium pressure and decrease LV filling leading to pulmonary congestion and low CO.
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What arrhythmia is common with mitral stenosis
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A-fib. May need to anticoagulate to prevent clot formation
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What is the etiology of mitral stenosis
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Rheumatic fever (type III hypersensitivity reaction), SLE, RA, Migrane med (Methysergide) - last three are rare
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How do you treat mitral stenosis
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Commissurotomy (break apart leaflets), Balloon valvotomy (breaks up calcium), Valve replacement
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What is the Abx prophylaxis for mitral stenosis
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Dental procedures: Amoxicillin. Nondental: Amp and Gent
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What are symptoms of mitral regurgitation
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Systolic murmur at apex and radiating to left axilla(Holosystolic in left decubitus position), prominent S3.
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What is the difference in etiology between mitral regurg. and mitral prolapse
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Mitral regurg. (abnormal leaflet or papillary muscle). MVP-leaflets balloon for unknown reason
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What are the treatments for mitral regurg (MVP)
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Asymptomatic MVP without regurg (EKG every 3-5 years), MVP with regurg (Abx prophylaxis for dental work), if have palpitations use BB
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What are the signs and symptoms of aortic stenosis
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Crescendo-decrescendo murmur radiating to neck, Prominent S4, Syncope-Dyspnea-Angina (classic triad), faint pulses, fatigue and pulmonary congestion as LV fails
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What is the etiology of aortic stenosis
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Calcium deposits on leaflets in older patients (if valve only has 2 leaflets calcium builds up more quickly), Younger patients usually see rheumatic fever as cause
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What is the treatment for aortic stenosis
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Surgery
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What are the signs and symptoms of aortic regurg.
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Diastolic murmur (thickened aortic root pulls leaflets apart), bounding pulse and wide pulse pressure (systolic minus diastolic), Austin Flint murmur (regurgent aorta flow plus mitral flow), palpitations, volume overload overstretches LV leading to failure and dyspnea,
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What causes aortic regurg.
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Abnormal leaflet or papillary muscle
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What is the treatment for aortic regurg.
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Left ventricle accomodates over the years to the extra volume until it can no longer stretch which requires valve replacement
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What is the prognosis of acute aortic regurg.
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Immediate surgery to avoid heart failure from the sudden overload on the LV which can't accommodate. Usually result of trauma
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What are the different types of prosthetic valves
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Mechanical-good longevity and need to anticoagulate (INR 2-3), Bioprosthetic (pig, human)-anticoag not needed, lower complication but higher failure rate
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Describe some functions of the pericardium
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Mesothelial cell secrete fluid (15-25cc), stabilizes, prevents overfilling, barrier to cancers from lungs (cancer results from secondary metastasis)
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What are out patient causes of pericardial disease
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Viral (Influenza, Coxsackievirus A & B, Varicella, AIDS, Epstein Bar) triggers inflammatory response leading to fluid accumulation
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What are some in patient causes of pericardial disease
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Trauma, Uremia (develop friction rub-need dialysis), MI (cell death triggers inflammatory response - Dressler syndrome post MI (autoimmune), Meds (Hydralazine, Procainamide), Other infections (C.difficile, diptheria, fungal), Rheumatoid, Radiation
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Describe the pathogenesis of pericardial disease
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Inflammation causes leakage of transudate then proteins start to leak out followed by white cells that give off an exudate
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How many cc's of fluid is needed before pericardial effusion shows on X-ray
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250cc (ECHO is best to evaluate)
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What factors determine if a pericardial effusion is silent of symptomatic
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Rate, Volume, Compliance
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What are the effects of cardiac tamponade
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Increased JVD, increased ventricle diastolic pressure, decreased CO and muffled heart sound
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What is constrictive pericarditis
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Recurrent pericarditis leads to fibrous, calcification of pericardial layers
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Describe the infectious endocarditis process
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A thrombus develops over injured endcardium leading to vegetations that attrack bacteria. The body tries to wall off the bacteria with fibrin which allows further proliferation of bacteria, eventually chips break off (seeding) and enter blood stream (fever)
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What is the primary infectious agent (endocarditis) in non intraveneous drug users
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Strep viridins, Staph aureus, Enterococci (usually aortic or bicuspid valve)
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What is the primary infectious agent (endocarditis) in intravenous drug users
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Staph. Aureus (tricuspid normally effected)
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What bacteria cause infectious endocarditis from surgery to replace a valve
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S. epidermidis, S. aureus, Gram negative organisms and fungi
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What bacteria cause infectious endocarditis from transient bactermia
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S. viridins, S. epidermidis, S. aureus
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True of False. An athlete should stop exercising when they have a virus
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True. Exercising can cause extra heart strain making it more susceptible to the virus damage
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What is the mechanism of myocarditis
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Virus (Coxsackie B) secretes toxins that change myocardium surface cells and the T-helper cell immune response attacks
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List some etiologies of myocarditis
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Viruses, Bacteria, Spirochetes (lyme disease-Borrelia burgdorferi), Antineoplastics(doxyrubison), Alcohol (cellular death), Peripartum (Twins or use of tocalytics to stop labor), CT disorders
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What is cardiomyopathy
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Structural abnormality of the myocardium causing HF symptoms
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What are the three categories of cardiomyopathy
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Dilated, Hypertrophic, Restrictive
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What are the characteristics of dilated cardiomyopathy
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Dilation of heart chambers that inhibits contractile forces and causes incompetent valve closure.
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How would you treat dilated cardiomyopathy
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ACEI, Positive inotropes (Frank-Starling mechanism eventually fails), BB
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What causes dilated cardiomyopathy
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Generally unknown but suspect viral and alcohol toxicity
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What causes hypertrophic cardiomyopathy
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Asymmetric hypertrophy of ventricular septum (muscle fibers are in disarray causing diastolic stiffness) that pushes into the LV causing poor ejection and poor coronary perfusion leading to arrythmias
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What portion of the population is hypertophic cardiomyopathy most common
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Athletes. Seems to be an autosomal dominance inheritence.
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How would you treat hypertrophic cardiomyopathy
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CCB not a positive inotrope
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What causes restrictive cardiomyopathy
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Endomyocardium Radiation or Metastatic tumor, Infiltration of myocardium by amyloid, sarcoid, scleroderma
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What are the characteristics of restrictive cardiomyopathy
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Abnormally rigid ventricles that impair diastolic filling but have normal systolic function
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