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what does the p wave on the ekg represent?
- atrial depolarization
- first positive wave in a normal cardiac cycle
- a positive p wave before a QRS complex means the impulse came from teh sa node
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what does the q wave on the ekg represent?
first negative wave after a p wave in a normal cardiac cycle
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what does the r wave on the ekg represent?
second positive wave in a normal cardiac cycle
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what does the t wave on the ekg represent?
ventricle depolarization
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f waves
indicate atrial flutter
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cardiac preload
- preload is stretch
- volume of blood received by the heart
- amount of volume being returned to the right side of the heart from systemic circulation
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cardiac afterload
- pressure or resistance the heart has to overcome to eject blood
- Afterload is squeeze
- The amount of resistance the left side of the heart has to overcome in order to eject blood
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pt teaching with a pacemaker
- notify MD if pulse is 5 beats over or under set rate
- take the radial pulse
- report dizzines, irregular heartbeats, palpitations
- avoid magnetic fields, high voltage, antitheft devices and large running motors
- may set off metal detectors
- use grounded appliances
- resume normal activity within 6 weeks
- don't lift anything over 10 lb or play sports before 6 weeks
- keep scheduled appointments
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What is ventricular fibrillation
- when the ventricle quivers and is unable to initiate a contraction
- causes: hyperkalemia, hypomagnesemia, electrocution, CAD, MI
- signs and symptoms: immediate loss of conciousness, no heart sounds, no peripheral pulses, no blood pressure, respiratory arrest, cyanosis, pupil dilation
- immediate defibrillation required
- meds given: epinephrine, vasopressin, amiodarone, magnesium
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premature ventricular contraction (pvc)
- ventricles fire prematurely
- causes: caffeine, alcohol, anxiety, hypokalemia, cardiomyopathy, ischemia, MI
- signs and symptoms: skipped beat/palpitations, fatigue, dizziness
- can lead to more sever dysrhythmias
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eventricular tachycardia
- 3 or more PVCs in a row
- ventricles rather than the SA node become the pacemaker
- causes: myocardial irritability, MI, and cardiomyopathy are most common; respiratory acidosis, hypokalemia, digoxin toxicity, cardiac catheters, pacing wires
- signs and symptoms: sudden onset of rapid heart rate, dyspnea, palpitations, light-headedness, angina
- can progress to ventral fibrillation
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Sinus tachycardia
- heart rate greater than 100 bpm
- causes: physical activity, hemorrhage, shock, medications (epinephrine, atropine, nitrates), dehydration, fever, MI, electrolyte imbalance, fear, hypoxia and anxiety
- signs and symptoms: angina, dyspnea. may be asymptomatic
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where is the sinus (sa) node located
right atrium
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premature atrial contraction
- atria fire an impulse before the sa node
- causes: hypoxia, cigarette smoking, myocardial ischemia, enlarged atria in valvular disorders, medications (digoxin), electrolyte imbalance, afib, heart failure
- signs and symptoms: palpitations otherwise asymptomatic
- therapeutic measures: beta blockers to slow heart rate
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ST segment
- time from completion of a contraction to recovery of myocardial muscle for the next impulse
- examined if a pt complains of chest pain
- appears inverted or depressed if a pt has ischemia
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atrial fibrillation
- rapid and chaotic atrial rate (350 - 600 bpm)
- increased stroke risk; blood pools in atria and thrombus may form
- causes: cigarette smoking, rheumatic or ischemic heart diseases, heart failure, hypertension, pericarditits, pulmonary embolism, postoperative coronary artery bypass surgery
- signs and symptoms: faint radial pulse (decreased stroke volume), may lead to left heart failure
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digoxin side effects
- fatigue
- nausea
- vomiting
- anorexia
- headache
- bradycardia
- cardiac arrhythmias
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Bumex
- potassium wasting diuretic
- side effects: hypokalemia, hypochloremia, hypomagnesmia, hyponatremia, dehydration, hypotension
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left sided heart failure
- blood backs up and congests pulmonary circulation causing edema in the pulmonary system
- left sided heart failure is all about the lungs
- hypertension is the major cause; increases arterial pressure and makes the left ventricle work harder
- valvular problems, cardiomyopathy, heart muscle infection are also causes
- signs and symptoms: pulmonary edema, shortness of breath, cyanosis, alveolar edema
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right sided heart failure
- blood builds up in the systems blood vessels
- major cause is left sided heart failure
- signs and symptoms: distended jugular veins, edema in peripheral tissues, abdominal organ hypertrophy, anorexia, nause, abdominal pain
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cor pulmonale
the right ventricle hypertrophies or fails because of increased pulmonary pressures
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pulmonary edema (acute heart failure)
- occurs when the left ventricle fails
- signs and symptoms: pinky, frothy sputum; increased heart rate and blood pressure (may drop); decreased PaO2 and increasing PaCO2
- therapeutic measures: goal is to reduce workload on left ventricle; fowlers position (easier lung expansion); oxygen given, morphine to decrease preload; IV meds
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care for patient with chronic heart failure
- O2 therapy; 2 - 6 L/min via nasal cannula (max 2L/min for COPD pts)
- balance rest and activity
- place in fowlers position
- monitor weight daily; report gains of 2 - 3 lb over 1 - 2 days
- prevent constipation
- teach to conserve energy when perfoming ADLs
- low sodium diet; spices, herbs and lemon juice replace salt
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exertional dyspnea
shortness of breath that increases with activity
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orthopnea
- dyspnea that increases when lying down
- 2 or more pillow usually used for sleeping
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paroxysmal nocturnal dyspnea (PND)
- sudden shortness of breath that occurs after lying flat for a time
- excess fluid accumulation in the lungs
- relieved by sitting upright for a short time; reduces amount of fluid returning to the heart
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dyspnea
- common symptom of left sided heart failure
- pulmonary congestion impairs gas exchange between the alveoli and capillaries
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continuous ECG monitoring
lead II usually provides a good view
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