anti-arrhythmic Flashcards
arrhythmias may occur from
- heart disease
- stress
- electrolyte imbalance
abnormal number of electrical impulses can generate-
cardiac arrhythmias
-from SA node or other sites
Antiarrythmics generally _____ myocardial excitability or the ability of the myocardium to respond to an electrical stimulus
depress.
- Pulse rate decreases
- Arrhythmias is corrected (what we want)
- Better control of rhythm
A brief period of time following the stimulation of a nerve during which the nerve will not respond to a second stimulus.
refractory period
by lengthening the refractory period,
the number of impulses or beats per minute decrease.
polarization
- Period of rest
- Before the heart undergoes a contraction
- Positive ions on outside of nerve cell and negative ions on inside.
When a stimulus passes along a nerve (contraction), the positive ions move inside and the negative ions move outside
depolarization
If the cell has a resting action potential of -70mV and then after an action it changes to -40mV, then it is said to be _____.
depolarized.
_____ refers to the degree of excitability of the heart muscle
threshold
The lowest intensity of a stimulus that will give rise to an effect
threshold
lowering the threshold-
increases the number of stimuli that will excite the heart muscle thus increasing heart rate
Lidocaine is a drug that raises the threshold-
It will reduce the number of stimuli that will excite the heart muscle thus reducing heart rate and it helps the heart rhythm stay more consistent
Another common classification of medications that has multiple uses. It works to control arrhythmias by inhibiting depolarization
calcium channel blockers
examples of calcium channel blockers
-Verapamil (Calan), Diltiazem (Cardizem)
calcium channel blockers Inhibit movement of Calcium through –
channels across myocardial cell membrane.
- Conduction through SA and AV nodes slowed
- Refractory period is prolonged
