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34 Cards in this Set
- Front
- Back
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what 4 properties make up action potential of heart
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automaticity, excitability, conductivity, contractility
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automaticity
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ability to make electric pulse spontaneously
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excitability
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ability to respond to electrical impulse
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conductivity
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ability to transmit electrical impulse to another cardiac cell
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contractility
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ability to contract after receiving a stimulus
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depolarization
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working, inside cell is positive
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repolarization
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resting, cell turns to normal negative state
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action potetnional
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5 phase cycle, describes changes in intracardiac voltage
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absolute refractory period
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no stimuli can generate another action potential, stability, phase 0-3
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relative refractory period
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strong stimulus can generate another action potential, unstable, can have lethal dysrhythmias, phase 3-4
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P wave
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atrial depolarization, normal round and upright (SA node)
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PR interval |
tracking the atrial impulse to the AV node, beginning of P wave to beginning of QRS complex |
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QRS complex |
ventricle depolarization |
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ST segment |
end of ventricle depolarization, beginning of ventricle repolarization |
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T wave |
ventricle repolarization |
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causes of dysrythmias |
enhanced automaticity, reentry, escape beats, conduction disturbance |
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enhanced automaticity |
cells fire automatically from ectopic site |
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causes of enhanced automaticity |
hypoxia, acidosis, electrolyte imbalance |
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reentry |
sluggish impulse or blocked pathway, impulse may travel backwards |
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causes of reentry |
ischemia, electrolyte imbalances |
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escape beats |
dominate pacemaker fails to initiate depolarization, impulse is generated from another site, AV or ventricles |
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A-fib |
firing all throughout atria, irregular rhythm, erotic, fast |
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pt with A-fib can feel when |
go into and out of A-fib |
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A-fib symptoms |
often asymptomatic, uneven pulse, racing or bounding heart, fluttering heart |
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causes of A-fib |
HTN, CAD, MI, HF, abnormal functioning of heart valves |
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A-fib risk factors |
male, caucasian, >60 yrs, obesity, lung disease (COPD), stimulants |
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Dx A-fib |
ECG 24 hr monitor, echo, stress heat |
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A-fib Tx |
beta blockers, antirhythmics, cardioversion, med management, ablation, maze, pacemaker |
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causes of A-fib |
cardiac surgery, trauma, MI, heart defect, syphilis, electrolyte imbalances |
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cardiac dysrhythmias types (4) |
sinus rhythmias, atrial rhythmias, junctional rhythmias, ventricular rhythmias |
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sinus rhythmias originate in and can be |
SA node - normal, tachy, brady |
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atrial rhythmias originate in and can be |
impulses originate in atrial ectopic sites - flutter, fibrilation |
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junctional rhythmias originate in |
impulse originates in AV node |
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ventricular rhythmias originate and can be |
impulse originates in ventricles - tachycardia, fibrilation |
