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139 Cards in this Set

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What does the right main coronary artery supply?
right side of heart + anterior left ventricle
What does the posterior descending artery (which branches off the right main coronary artery) supply?
posterior right side
What does the left anterior descending artery supply?
anterior surface of the left side of the heart
What does the left circumflex artery supply?
the lateral portion of the left side of the heart and a portion of the left posterior
3 physiologic characteristics of the cardiac conduction cells are
1. Automaticity: the ability to initiate an electrical impulse
2. Excitability: the ability to respond to an electrical impulse
3. Conductivity: the ability to transmit an electrical impulse from one cell to another
The 4 main landmarks of the cardiac conduction system are:
1. SA node
2. AV node or AV junction
3. Bundle of HIS
4. Purkinje fibers
The SA Node (primary pacemaker of the heart)
* fires 60 - 100 impulses per minute
* located in the right atrium
* impulse causes contraction of the atria
* conducts impulses along the internodal pathway
The AV node
* located in the right atrium near the tricuspid valve
* transmits impulse after slight delay (for filling) to the ventricles
* has its own intrinsic beat of 40 - 60 impulses per minute
The Bundle of HIS
* located in the septum separating the ventricles, bifurcating into a left bundle branch and a right bundle branch
* impulse transmitted to the Purkinje fibers
The Purkinje fibers
* the point at which the myocardial cells are stimulated into ventricular contraction
* the ventricles also have an intrinsic beat of 30 - 40 impulses per minute
What does it mean that cardiac cells are polarized in the resting state?
Means that the cell is negatively charged inside and positively charged outside
What is depolarization?
* when an impulse is initiated, the cell membrane permeability changes and Na enters cell

* the end result is that the cell becomes + charged
* muscle contraction follows as the cells transmit the impulse to one another
What is repolarization?
* repolarization is the return of the cell to its resting state
* corresponds to the relaxation of the cardiac muscle
* after the rapid influx of Na into the cell during depolarization, the permeability of the cell membrane to Ca is changed
* The increase in intracellular Ca is slower
What is the refractory period?
prolonged period during which the heart cannot be stimulated (protecting the heart from sustained contraction or tetany, which would result in cardiac death)
What is the ABSOLUTE refractory period
The heart cannot be stimulated to contract regardless of strength of stimulus
* corresponds to depolarization and early part of repolarization periods
What is the RELATIVE refractory period?
*The heart can be stimulated to contract during this period if the stimulus is strong enough.
* corresponds to the late part of repolarization
What are the 2 major components to the cardiac cycle?
1. systole
2. diastole
Describe systole
When the rising pressure in the L and R ventricles leads to the forceful ejection of blood from the ventricles
Describe diastole
A filling period when the ventricles relax, the valves open
Describe cardiac output
* formula
* ave adult cardiac output
* the amount of blood pumped by the ventricle in a given period
* CO = Stroke volume * Heart rate
* average adult cardiac output is 5L per minute
Describe stroke volume
* ave stroke volume
* ave heart rate
* The amount of blood ejected per heartbeat
* The average resting stroke volume is about 70 mL
* The average heart rate is 60 - 80 bpm
What effects the heart rate?
1) autonomic nervous system (parasympathetic and sympathetic nervous system responses)
2) increase in circulating catecholamines
3) excess thyroid hormone
4) CNS/baroreceptors which responds to changes in blood pressure
5) certain medications
6) acidotic / alkalotic state
What are catecholamines?
*hormones released by the adrenal glands in situations of stress or low blood sugar
*catecholamines have the effect of increasing heart rate, blood pressure and blood sugar levels as well as activating a "fight or flight" response
* epinephrine and norepinephrine are examples
What is the effect of thyroid hormone
Increases cardiac output
Increases heart rate
Increases ventilation rate
Increases effect of catecholamines
How do beta-blockers effect heart rate?
Beta blockers block the beta adrenergic impulses and lower heart rate and decrease cardiac output
* When the beta adrenergic receptors are stimulated, heart rate increases, the force of contraction increases and conduction is enhanced
What is a chronotropic effect?
the term chronotropic effect has to do with how a stimulus effects the heart rate (eg beta adrenergics have a + chronotropic effect, digoxin has a - chronotropic effect)
What is an inotropic effect?
describes how a stimulus effects the force of a muscle contraction
What is a dromotropic effect?
*Describes how a stimulus effects the velocity of the impulse through the AV node
* This can work both ways, if the velocity is too fast, the muscle cannot respond quickly enough (refractory period)
Three major variables that determine stroke volume
1. Contractility
2. Preload
3. Afterload
What is Contractility?
* Contractility is the degree of force with which the the heart is able to contract.
* Increased contractility results in increased stroke volume
What effects the heart's contractility?
* Contractility is depressed by hypoxemia, acidosis (lactic acid means that the metabolism is anaerobic), and certain meds (beta adrenergic blocking meds such as atenolol
* Contractility is enhanced by circulating catecholamines, sympathetic neuronal activity and certain meds (dopamine, dobutamine, digoxin)
What is Preload?
the degree of stretch of the cardiac muscle fibers at the end of diastole (think rubber band)
What is Starlings Law
As the volume of blood returning to the heart increases, muscle fiber stretch increases, resulting in stronger contraction and greater stroke volume
What is Afterload?
The force (resistance) at which the ventricle pumps against; When the afterload increases, the stroke volume decreases
What effects afterload?
Hypertension increases afterload; ACE inhibitors or other meds that decrease blood pressure, decrease afterload; peripheral vasodilation decreases afterload
What is the ejection fraction?
* the percentage of the end diastolic volume that is ejected with each stroke
* ejection fraction = (stroke volume / end diastolic volume) * 100
* Normally, about 42 - 50% or more of the end-diastolic volume is ejected by the normal heart
* can be used as a measure of contractility: the ejection fraction decreases if contractility is depressed
Cardiac Assessment (PQRST - R)
P What PROVOKED this pain or discomfort
Q What is the QUALITY of the pain
R Where does it radiate to?
S What is the strength (0-10) fo thepain
T TIME How long have you had this pain
R What RELIEVED your pain in the past
Changes in the aging heart--adequate cardiac output in normal circumstances but limited ability to respond to stress
1. Decreased elasticity and widening of the aorta (decr. contractility)
2. Thickening and rigidity of the cardiac valves (increased ejection time)
3. Increased connective tissue in the AV and SA nodes (delayed conduction)
Warning signs of MI / heart disease in women
1. upper back pain, fatigue
2. prodromal period of 2 weeks with shortness of breath, sleep changes and fatigue
Anatomical differences in women
1) smaller heart and vessel size mean more chance for occlusion, more difficulty with cardiac catherization and angioplasty
2) protective effect of estrogen on premenopausal women (estrogen regulates vasomotor tone and response to vascular injury)
4 Non-modifiable risk factors for heart disease
1. + family history for premature coronary artery disease
2. increasing age
3. gender (men and postmenopausal women)
4. race (higher incidence in african americans than in caucasians)
8 modifiable risks of heart disease
1. hypertension
2. hyperlipidemia
3. smoking
4. elevated glucose level
5. obesity
6. physical activity level
7. use of oral contraceptives
8. type A personality
6 Typical signs/symptoms of people with cardiac disorders
1. chest pain or discomfort
2. shortness of breath or dyspnea
3. edema or weight gain
4. palpitations
5. fatigue
6. dizziness, syncope, loss of consciousness
4 important points to remember about assessing cardiac symptoms
1. women often have atypical symptoms
2. little correlation between the severity of the symptom and the gravity of the cause
3. poor correlation between the location of the pain and the source
4. patient may have more than one clinical condition occurring simultaneously
What is the character/location of pain of ANGINA?
1) substernal or retrosternal pain
2) may radiate to inside of arm, neck or jaw
What is the duration of pain/discomfort with ANGINA?
5 - 15 minutes
What are the common precipitating events to ANGINA?
4 Es:
1. exercise
2. exposure to cold
3. excitement
4. eating
What are the relieving measures for ANGINA?
1. Rest
2. Nitroglycerin
3. Oxygen
What is the character and location of pain/discomfort with Myocardial Infarction?
1) substernal pain that spreads throughout the whole chest
2) pain in shoulders/hands may be present
3) nausea, dizziness, diaphoresis, feeling of doom
What is the duration of pain/discomfort with MYOCARDIAL INFARCTION
GREATER THAN 15 MINUTES
What is a common precipitating event for MI?
occurs spontaneously, but may follow unstable ANGINA
What are relieving measures for MYOCARDIAL INFARCTION?
1) morphine sulfate
2) successful reperfusion of blocked coronary artery
What is the duration of pain/discomfort for PERICARDITIS (inflammation of the pericardium)
Intermittant
What is the character/location of pain and discomfort in PERICARDITIS?
1) Sharp substernal pain
2) Pain to left sternum
3) Pain may be referred to epigastrum, neck, arms & back
What is the typical duration of pain/discomfort for PERICARDITIS?
intermittant pain
What is the precipitating event/s for PERICARDITIS?
1) aggravated by movement
2) pain increases with inspiration, coughing, swallowing or rotation of the trunk
What are the relieving measures for PERICARDITIS?
1) sitting upright
2) analgesia
3) anti-inflammatory medication
What is the character and location for PLEURITIC PAIN (arises from the inferior portion of the pleura)?
1) sharp substernal pain
2) pain to left of sternum
3) may be referred to the costal margins or upper abdomen--pt may be able to localize pain
What is the typical duration for PLEURITIC PAIN?
30+ minutes
What are precipitating factors for PLEURITIC PAIN?
occurs spontaneously, but pain may increase with inspiration
What relieves PLEURITIC PAIN?
1)rest, time
2) treatment of underlying cause (broncho dilators)
What is the character/location of GI-esophageal pain?
1) substernal pain; maybe projected around chest and shoulders
2) reflux--hiatal hernia; ingestion
What is the typical duration of GI-esophageal pain?
5 - 60 min.
What are the precipitating factors for GI esophageal pain?
recumbancy, cold liquids, exercise
What are relieving measures for GI-Esophageal pain?
food, antacid, nitroglycerin relieves spasms
What is the character and location of pain for ANXIETY ATTACKS?
pain all over the chest; hyperventilating, numbness, tingling
What are the precipating factors for ANXIETY ATTACKS>?
stress, emotional stress, tachypnea
What is the typical duration for an ANXIETY ATTACK?
2 - 3 min
What are the relieving measures for ANXIETY ATTACKS?
removal of stimulus, relaxation
Cardiac Physical Assessment always includes:
1) evaluation of effectiveness of heart as a pump (reduced pulse pressure, cardiac enlargement, murmurs or gallop rhythms)
2)filling volumes and pressures (est by jugular vein distention, lung congestion, peripheral edema)
3) cardiac output (hr, pulse pressure, color skin, urine output)
4) compensatory mechanisms (ie. increasing hr)
Why do cardiac patients have to avoid straining?
Val Salva triggers a vagal response causing the heart to slow down which may cause syncope in some patients
What are cardiac patients on anticoagulants screened for?
bloody stools and urine
What is pulse pressure
the difference between the systolic and diastolic pressures (normally 30 - 40 mm/hg)
What increases pulse pressure?
Things that increase systolic pressure or decrease diatolic pressure
1. conditions that elevate the stroke volume (anxiety, exercise, bradycardia)
2. conditions that decrease vascular resistance (fever)
3. conditions that reduce artery distension (atherosclerosis, aging, hypertension)
What conditions decrease pulse pressure
Things that decrease systole or increase diastole are:
1. reduced stroke volume
2. reduced ejection velocity (shock, HF, hypovolemia, mitral regurgitation)
3. obstruction to blood flow during systole (mitral or atrial stenosis)
What (8) skin conditions might one observe on a cardiac physical assessment?
1. pallor
2. peripheral cyanosis
3. central cyanosis
4. xanthelasma (the little yellow cholesterol pimples)
5. reduced skin turgor (dehydration)
6. cool extremities (with cardiogenic shock) and diaphoresis
7. ecchymosis (from those receiving anticoagulant therapy)
8. scars and tissue surrounding implanted devices
What is an arrhythmia/dysrhythmia??
Uncoordinated atrial/ventricular contractions
What is fibrillation?
rapid and irregular or out of phase contractions in which control of the heart rhthym is taken away from the SA node by rapid activity in other heart rhythms (like a squirming bag of worms)
What is heart block
damage to the av node interferes with the ventricles ability to receive impulses
What are mumurs?
Abnormal heart sounds which may indicate valve problems:
1. imcompetant valve: backflow
2. stenotic valve: opening is narrowed
What is orthostatic (or postural) hypotension?
When BP drops significantly after the patient assumes an upright posture (usually accompanied by syncopy, dizziness, light headedness)
What are the 3 most common causes of orthostatic hypotension in cardiac patients
1. reduced volume of fluid in the circulatory system (intravascular volume depletion or dehydration)
2. Inadequate vasoconstrictor mechanisms
3. insufficient autonomic effect on vascular constriction
How to assess for postural changes
1. start lying down for 10 min before first bp and hr
2. wait for 1-3 min after each postural change
3. sitting, then standing
What normal postural responses should you see?
1. heart rate increase of 5 - 20 bpm (to offset reduced stroke volume)
2. an unchanged or slightly decreased (of up to 10mm)systolic pressure
3. a slightly increased pressure of 5 mm in diastolic pressure
6 Lung Assessment findings exhibited by cardiac pts
1. tachypnea
2. Cheyne Stokes (fast shallow w apnea)
3. Hemoptysis (pink frothy sputum)
4. dry cough (pulmonary congestion)
5. crackles (heart failure or atelectasis)
6. wheezes (compression sm airways/pulmonary edema)
5 reasons to do Laboratory Tests on cardiac patients
1. diagnose acute MI
2. Assess degree of inflammation
3. Screen for coronary artery disease risk factors
4. determine baseline values and monitor med response
5. Indentify other abnormalities that may effect treatment
5 steps to heart auscultation
1. patient in supine position
2. start in the apical area
3. progress up the left sternal border to the pulmonic and aortic areas
4. S1 evaluated for intensity and splitting
5. S2 evaluated for intensity and splitting
5 things to document about extra heart sounds
1. location
2. timing
3. intensity (1=very faint 6= so loud you don't need stethoscope)
4. Pitch (high, medium, low)
5. Quality of sound (blowing, harsh, musical)
Describe extra heart sound: snaps and clicks
* Usually heard in diastole in the Left Sternal border
* sounds like a high pitched pressure sound then an opening snap of mitral valve
* most often associated with stenosis of the mitral valve from rheumatic heart disease
What differences in heart sounds would you expect to hear in the elderly?
1. 90% of elderly have an S4 sound
2. 60% have a slight systolic ejection murmur (S2 splitting) resulting from sclertoic changes in aortic leaflets
What are the 3 roles of nurses in interpreting heart sounds?
Depends on level of expertise
1. recognizing a sound that is not normal
2. recognizing patterns and reporting to physician
3. differentiate among dysrhythmias and respond accordingly
What is pericarditis?
An inflammation of the pericardium that hinders the production of serous fluid causing sternum pain and creaking noise
What is a complication of pericarditis
*Over time, the adhesions formed s/t pericarditis cause inflammation and a great deal of inflammatory fluid in the cavity.
* This fluid compresses the heart "cardiac tamponade" (heart plug) and must be drained
How to auscultate a friction rub sound
Friction rub (most often from pericarditis) is heard best in the lower left sternal border when the patient is sitting up/leaning forward
* it is a harsh grating sound during both systole and diastole
Describe normal postural blood pressure and heart rate changes
1. slight decrease in systolic pressure (10 mm)
2. slight increase in diastolic pressure (5 mm)
3. heart rate increase (5-20 bpm)
Name the 3 most common causes of orthostatic hypotension in cardiac patients
1. reduced volume of fluid in the circulatory system
2. inadequate vasoconstriction
3. insufficient autonomic effects on vascular constriction
What part of the heart does heart percussion identify
left border of the heart
Describe s1
1. Closure of the mitral and tricuspid valves
2. The time between s1 and s2= systole
3. best heard at the apex of the heart
Describe s2
1. Closure of the aortic and pulmonic valves (pulmonic may lag slightly and you may hear a 2nd s2 accentuated at inspiration b/c more blood is ejected at inspiration)
3. Best heard at the base of the heart
What are gallop sounds
A third sound heard that makes the heart beat almost sound like a gallop (s3 and s4)
Describe s3
* rapid ventricular filling
* normal finding in young children & elderly
* in adults: indicates heart failure--ventricles fail to eject all of the blood during systole
* best heard with patient lying on left side
Describe s4
* heard during atrial contraction
* enlarged or hypertrophied heart resistant to filling
What might indicate a left ventricular enlargement
apical pulse below 5th ics
What is a thrill?
a purring senstation that indicates abnormal turbulent blood flow
What is the hepatojugular reflex--
*liver engorgement occurs b/c decr venous return
* pt lies supine, 30-60s note rise of jugular venous distention (inability for the right side of the heart to accom. incr. volume)
Why do you assess bladder distention in a cardiac assessment?
to rule out a mechanical reason (distended bladder) for low urine output
6 observations of extremities in cardiac physical assessment
1. decreased cap refill time (hypotension/hf)
2. quality and equality of pulse
3. discomfort, pain, parasthesia
4. decr temp and color of extremities
5. peripheral edema
6. wounds, hair distribution
What do BUN and creatinine levels in a cardiac patient indicate
1.High BUN, High Creatinine = decreased renal perfusion s/t cardiac output
2. High BUN, Normal Creatinine=fluid volume deficit (diuretic therapy or dehydration)
Why do you have to monitor glucose so closely in diabetic cardiac patients?
1. incr phys stress incr epinephrine secretion which increases glucose levels
2. monitor glycosylated hemoglobin aka Hemoglobin A1c(normal 4-6%) which reflects blood glucose levels over 2-3 months (important for cvd prevention)
What information does cardiac enzyme analysis provide?
*enzymes are released when there is cell damage
*certain specific myocardial isoenzymes move into blood at various times in relation to the timing of the MI
What information does troponin provide?
* Gold statndard for MI diagnosis--isomers I & T are specific to cardiac muscle
* troponin is a protein that regulates the contractile process
* Increases 2-4 hours after MI
* Peaks 12 hours after MI
* Returns to normal 4-10 days after MI
What information does myoglobin provide?
* heme protein that transports o2 found in cardiac & skeletal muscle
* starts to increase 2-4 hours after MI (can't diagnose MI but can rule out)
* Peaks 12 hours after MI
* Returns to normal 24 hours after MI
5 effects of the sympathetic nervous system?
*inc rate of SA node pacing
*inc rate of conduction
*inc force of contraction
*inc irritability of foci
* constricts arteries (inc bp and blood flow)
What are 5 effects of the parasympathetic nervous system?
* decr rate of SA node pacing
* decr rate of conduction
* decr force of contraction
* decr irritability of atrial and junctional foci
* dilates arteries (decr bp and blood flow)
How does the sympathetic nervous system work?
release of norepinephrine (adrenaline like) that activates adrenergic receptors (B1) which produces cardiac excitatory effects
How does the parasympathetic nervous system work?
secretes acetylCHOLine which activates CHOLINergic receptors to produce cardiac inhibitory effects (note vagus nerve is the main pathway-vasovagal stimulation = inhibitory)
**note GI tract is stimulated by the parasympathetic innervation
How does epinephrine work?
Norepinephrine's "brother" epinephrine is secreted into the blood stream by the adrenal glands for a more potent stimulatory effect
What are vagal maneuvers
an induced parasympathetic response may be used to: 1) therapeutically depress an irritable focus in the atria or AV junction (supraventricular tachycardia converts to sinus rhythm)
2)to slow AV node conduction to make AV node more refractory to depolarization
3) induced gagging & carotid sinus massage
What do the small and big boxes on a EKG strip represent?
sm box = 0.04 seconds,
big box= 0.2 seconds
How do you calculate HR on an EKG?
Count how many R waves in 6 seconds and multiply by 10
What does a depressed ST segment indicate?
ST segment should be flat and horizontal, most importantly, even with the base line== myocardial ischemia
What does an elevated ST segment indicate?
ST segment should be flat and horizontal, most importantly, even with the base line== evidence of an evolving MI
What tests measure the intrinsic pathway for coagulation?
*Partial thromboplastin time (PTT) and activated ptt (aPTT)measure the effects of HEPARIN (intrinsic pathway)
What PTT values should be observed in heparin therapy
Patients receiving heparin should have their values @ 1.5 - 2.5 times their baseline values (ref range 25-38s)
What tests measure the extrinsic pathway for coagulation?
Prothrombin Time (PT) and the International Normalized Ratio (INR) measure the extrinsic pathway and are used to measure the effects of coumadin
What INR would you expect in patients wih heart valve replacement
2.5-3.5
What is the difference between creatine kinase (CK) and CK MB?
Creatinine Kinase is released in all muscle damage, CKMB is exclusively found in muscle tissue
Name 2 major sources of cholesterol
1. diet
2. liver (where cholesterol is synthesized)
What is Fluoroscopy and what is it used for?
1. "Xray" of hear with cardiac and vascular pulsations
2. Used for positioning intravenous pacing electrodes and for guiding cardiac catheterization
What is Chest xray used for
Used to: 1) determine the size, position, location and contour of heart, 2) reveals calcifications and 3) confvirms placement of catheters, pacemakers, & catheters
What are the normal levels of cholesterol, triglycertides, LDL and HDL?
Total Cholesterol: < 200
Triglycerides: 40 -150 mg/Dl
HDL: 35 - 85 women (35-65 men)--the goal would be 60 or more
LDL: less than 130 (the goal would be 100 or less)
What are low density lipoproteins?
primary transporters of cholesterol and triglycerides to the cells
What are high density lipoproteins
primary transporters of cholesterol and triglycerides away from the cells
What is the purpose of measuring cholesterol, triglycerides and lipoproteins?
To evaluate a person's risk for developing atheroslerotic disease
What is the significance of calcium in the blood labs for cardiac evaluation?
* hypo/hyper calcemia cause dysrhythmias
* calcium is necessary for clotting and neuromusc activity
What is the significance of potassium in the blood labs for cardiac evaluation?
* hypokalemia causes cardiac irritability and predisposes pt. to digitalis toxicity
* hyperkalemia = myocardial deptression and ventricular irritability
* many diuretics cause K depletion
8 Factors that contribute to cholesterol levels
1.age
2.gender
3.diet
4.exercise
5. genetics
6.menopause
7.tobacco use
8.stress
What is the significance of magnesium in the blood labs for cardiac evaluation?
hypo mag lengthens QRS and predisposes patient to life threatening dysrhythmias
What is sinus arrhythmia?
when the pulse (heart) rate increases during inhalation and slows during exhalation