NUR 213 Care of Patient with Dysrhythmias study guide

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NUR 213 Care of Patient with Dysrhythmias
study guide

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Care of Patients with Dysrhythmias – Chapter 34

- Cardiac dysrhythmias are abnormal rhythms of the hearts’ electrical
system that can affect its ability to effectively pump oxygenated blood
throughout the body
- When the heart does not work effectively as a pump, perfusion to
vital organs and peripheral tissues can be impaired, resulting in
organ dysfunction or failure
- Potential Causes:
* CAD
* Electrolyte imbalances
* Impaired oxygenation
* Drug toxicity
- Most often in older adults (but can happen at ANY age)

Review of Cardiac Electrophysiology
Automaticity
❖ Generate electrical impulse
❖ NORMALLY, only SA node cells can generate an electrical
impulse, BUT under certain circumstances any cardiac cell may
produce electrical impulses independently and create
dysrhythmias
❖ Disturbances = Increased or decreased pacing function
Excitability
❖ Respond to electrical impulse and depolarize
Conductivity
❖ Transmit electrical impulse
❖ Excitable cells depolarize in rapid succession from cell to cell
until all cells have depolarized
❖ Wave of depolarization causes the deflection of the ECG
waveforms, which is the P wave and QRS wave
Contractility
❖ Shorten fiber length in response to electrical impulse, causing
sufficient pressure to push blood forward thought the heart
❖ “Mechanical activity of the heart”
Depolarization
❖ Occurs when the normally negatively charged cells within
the heart muscle develop a positive charge
Repolarization
❖ Return to resting state
❖ Cardiac cells that were depolarized (positive) return to negative
charge
SA node (sinoatrial)
❖ Heart’s primary pacemaker
❖ Generate electrical impulses 60-100 bpm
❖ Richly supplied by the SNS and PNS, which  decrease the 
rate of discharge of the SA node


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