chapter 49

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chapter 49
2012-11-27 21:30:00
chapter 49

chapter 49
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  1. atria
    the two upper chambers of the heart
  2. atrioventricular AV node
    the part of the cardiac condution system between the atria and the ventricle
  3. bundle of his
    specialized muscle fibers that conduct electrical impulses from the AV node to the ventricular myocardium
  4. cardioversion
    the use of electroshock to convert an abnormal cardiac rhythm to a normal one
  5. defibrillator
    a machine that delivers an electroshock to the heart through electrodes placed on the chest wall
  6. ectopic
    originating outside of the normal tissue
  7. infarction
    an area of tissue that has died from lack of blood supply
  8. ischemia
    decreased blood flow to a body part or organ , caused by constriction or blockage of the supplying artery
  9. myocardial
    pertaining to the heart muscle
  10. sinoatrial SA node
    the pacemaker of the heart , it is located in the right atrium
  11. ventricles
    the two lower chambers of the heart
  12. the heart goes through two phases
    systole and diastole
  13. during systole both the _____ and the _____ contract and empty blood
    atria and the ventricles
  14. during diastole the ______ phase of the heart the chambers refills with blood
    the relaxation
  15. SA node
    initiates each heart beat ( pacemaker of the heart)
  16. normal sinus rhythm NSR
    refers to a regular heart rate that falls within average range 60 to 80 beats per minute
  17. sinus bradycarida
    heart rate less than 60 beats/min
  18. tachycardia
    a heart rate greater than 100 beats per minute
  19. arrhythmia
    irregular cardiac rhythm
  20. conduction system
    • av
    • sa
    • bundle of his
    • purkinj fibers
  21. polarization
    resting state of myocaridal wall

    no electrical activity in the heart

    flat line on ECG
  22. depolarization
    contraction phase

    stimulates the myocardium
  23. repolarization
    resting state after depolarization
  24. p wave
    first deflection from baseline atrial depolarization
  25. PR segment
    return to baseline after atrial contraction
  26. PR interval
    time from the beginning of atrial contraction to the beginning of ventricular contraction
  27. QRS complex
    contraction of both ventricles
  28. ST segment
    time between the end of ventricular contraction and the beginning of ventricular recovery
  29. T wave
    repolarization of the ventricles
  30. QT interval
    between the beginning of the QRS complex through the T wave
  31. U wave
    occasionally seen as a small waveform after the T wave
  32. ends with pril
    ACE inhibitors vasodilation reduce workload of the heart
  33. MVP
    mitral valve prolase
  34. another name for right-sides heart failure
    cor pulmonale
  35. left sided heart failure causes
    lung congestion
  36. drugs that end with lol
    beta blockers  reduce the heart rate and cardiac output open blood vessels

    tenormin , lopressor , ziac , inderal
  37. calcium channel blockers
    norvasc , lotrel , cardizem , procardia , vascor

    interrupt the movement of calcium into the heart , cause vasodilation
  38. angiotensin II receptor blockers
    cozzar , atacand , diovan

    block the action of chemicals that cause vasoconstriction
  39. horizontal lines on the ECG paper
    determination of the intensity of the electrical activity strength of the heart beat
  40. one small 1-mm square passes the stylus every
    0.04 seconds
  41. 5-mm square passes the stylus every
    0.2 seconds
  42. 5 large squares
    1 second
  43. large squares represent
    0.2 seconds
  44. ECG paper travels pass the stylus at
    25 mm per second
  45. standard leads are called
    bipolar leads

    lead I : records tracings of right arm and left arm

    lead II : records tracings of right arm left leg and is the lead recorded on a cardiac monitor or the rhythm strip at the bottom of the 12-lead ECG

    lead III records tracings between left arm and left leg 
  46. frontal leads includes
    leads I , II , III , aVR , aVL , and aVF
  47. horizontal plane leads include
    six precordial or chest leads
  48. augmented leads
    unipolar leads a single positive electode that uses the right leg for grounding

    • aVR
    • aVL
    • aVF
  49. aVR records
    the electrical activity of the atria from the right shoulder P wave and QRS complexes are deflected below the baseline
  50. aVL records
    lateral wall of the left ventricle from the left shoulder
  51. aVF records
    inferior surface of the left ventricle from the left leg
  52. precordial lead V1
    V1 fourth intercostal space left of the sternum
  53. V2 precordial lead
    fourth intercostal space just to the left of the sternum
  54. V3 precordial lead
    midway between V2 and V4
  55. V4 precordial lead
    fifth intercostal space left midclavicular line
  56. V5 precordial lead
    horizontal to V4 in the left anterior axillary line
  57. V6 precordial lead
    horizontal to V4 in the left midaxillary line
  58. standardization
    10 mm square
  59. usual speed of an ECG recording is
    25 mm/sec
  60. artifacts
    erractic movement of stylus on ECG paper from outside interference

    • wandering baseline
    • somatic tremor
    • alternating current interference
    • interrupted baseline
  61. wandering baseline
    stylus gradually shifts away from center of paper caused by patient movement or poor electrode attachment
  62. alternating current AC interference
    • uniform small spikes
    • nearby equipment or wiring  
  63. somatic tremor
    muscle movement

    jagged peaks irregular height and spacing with a shifting baseline

    discomfort , apprehension , movement , talking , uncontrollable body tremors
  64. interrupted baseline
    electrical connection interrupted

    stylus moves up and down or straight line across the top or the bottom of the paper

    dislodges electrode

    broken lead wires

    detached leads
  65. normal ECG appearance
    each beat of the heart shows a P wave followed by a QRS complex
  66. calculate heart rate
    count the number of P waves in a 6- second strip ( 30 large squares ) multiply by 10
  67. ventricle contraction rate
    count the number of complete QRS complexes in 6 seconds and multiply that by 10 contractions in 1 minute
  68. if the patient's heart is in a regular rhythm each cardiac cycles occurs within the same time frmae and each cardiac cycles occurs exactly the same length of time apart
    normal sinus rhythm
  69. sinus arrhythmias
    heartbeat is altered
  70. premature atrial contraction PAC
    atria contract before they should abnormally P wave or and extra P
  71. atrial flutter
    extremely rapid atrial rate up to 300 beats / min
  72. premature ventricular contraction PVC
    ventricles contract before the should QRS complex appears befor P wave
  73. ventricular tachycardia

    101 to 250 beats/min
  74. ventricular fibriliation

    life-threatening arrhythmia heart muscle quivering uncontrollably unable to pump blood

    no pulse
  75. asystole
    no heartbeat

    flatline on ECG
  76. digitalis
    causes scooping of ST segment in V5 and V6
  77. potassium
    can cause life-threatening arrhythmias
  78. myocardial infraction
    causes specific ECG changes based on the phases

    the three most common changes: elevated ST segments , inverted upside-down T waves and abnormal pathological Q waves
  79. cardiac event monitor
    worn up to 30 days to catch events that are difficult to record in 24-hour holter monitor period
  80. holter monitor period
    • 24 hour
    •  portable system for recording the cardiac activitiy