Cardiac Dysrhythmias

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Cardiac Dysrhythmias
2011-10-09 17:00:59

definition and Description of different Cardiac dysrhythmias
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  1. cardiac rhythm
    • pattern (or pace) of the heartbeat produces a rhythmic
    • pattern which greatly influences the heart's ability to pump blood effectively
  2. dysrhythmias
    originating in the atria
    • sinus bradycardia, sinus tachycardia, premature atrial contractions,
    • supraventricular tachycardia, and atrial fibrillation
  3. sinus
    • dysrhythmia
    • that proceeds normally through the conduction pathway but at a slower than usual
    • rate (<60 beats/minute). The danger is the slow rate may be insufficient to
    • maintain cardiac output. Tx is atropine sulfate (a cholinergic blocking agent)
  4. sinus
    • faster
    • than normal heart rate that proceeds normally through conduction system (100 -
    • 150 beats/min.) It occurs in pt's with healthy hearts as a physiologic response
    • to strenuous exercise, anxiety and fear, pain, fever, hyperthyroidism,
    • hemorrhage, shock, or hypoxemia
  5. premature
    atrial contractions
    • - early electrical impulse initiated by neural tissue. Is
    • identified by an irregularity in the underlying rhythm. The P wave may differ
    • slightly because it is initiated somewhere in the atria other than the SA node.
    • Causes: caffeine, nicotine or other sympathetic nervous system stimulants
  6. ectopic
    • one
    • that initiates an electrical impulse independently of the SA node, can lead to
    • more serious dysrhythmias such as supraventricular tachycardia
  7. supraventricular
    • heart rate has a consistent rhythm, but beats at a dangerously
    • high rate (>150 beats/min). Diastole is shortened, cardiac output drops
    • dangerously low and heart failure can occur. SIGNS/SYMPTOMS: tachycardia,
    • angina, hypotension, syncope, and reduced renal output. TX: Digitalis,
    • Adrenergics, and calcium channel blockers (all used to slow HR)
  8. atrial
    • a single atrial impulse outside the SA node causes the atria
    • to contract at an exceedingly rapid rate (200 - 400/min). See a characteristic
    • sawtooth pattern
  9. atrial
    • several areas in the right atrium initiate impulses
    • resulting in disorganized, rapid activity. The atria quiver rather than
    • contract. TX: chemical cardioversion drugs, antidysrhythmics, heparin,
    • coumadin, Maze procedure
  10. Maze
    • the surgeon makes a new conduction pathway (used when pt's
    • fail to respond to cardioversion)
  11. heart
    • dysrhythmia
    • originating in the AV node, is a interference with transmission of impulses.
    • Are three types (first, second, third
  12. first
    and second degree heart block
    • the
    • impulse is delayed
  13. 3rd
    degree heart block
    • also called complete heart block, the atrial impulse never
    • gets through and the ventricular rate is slow (30-40 beats/min).
    • TX: pacemaker insertion
  14. ventricular
    • premature ventricular contractions, ventricular
    • tachycardias, and ventricular fibrillation
  15. premature
    ventricular contractions
    • a ventricular contraction that occurs early and
    • independently in the cardiac cycle before the SA node initiates an electrical
    • impulse. SYMPTOMS: flutter, pallor, nervousness
    • * PVC's are precursors of lethal dysrhythmias
  16. ventricular
    • caused by a single, irritable focus in the ventricle that
    • initiates and then continues the same repetitive pattern. The ventricles beat
    • very fast (150-250) and cardiac output is decreased. May lose consciousness and
    • become pulseless, often requires defibrillation and may progress to ventricular
    • fibrillation
  17. ventricular
    • rhythm of a dying heart. PVC's or ventricular tachycardia
    • can precipitate it. The ventricles do not contract effectively and there is no
    • cardiac output. CPR and immediate defibrillation necessary
  18. AICD automatic
    implanted cardiac defibrillator
    • internal electrical device used for recurrent serious
    • tachydysrhythmias
  19. pacemakers
    • provides an electrical stimulus to the heart muscle to treat an ineffective
    • bradydysrhythmia(slow abnormal rhythm)
  20. two
    modes that pacemakers function in
    demand(synchronous) or fixed-rate(asynchronous)
  21. demand
    mode pacemakers(synchronous)
    • self-activate
    • when the pt's pulse falls below a certain level
  22. fixed-rate
    • produce an electrical stimulus at a preset rate (usually
    • 72-80beats/min) despite the pt's natural rhythm