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29 Cards in this Set
- Front
- Back
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What is a dysrhythmia?
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Any deviation from the normal rhythm of the heart.
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What is an antidysrhythmic?
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A drug used for the treatment and prevention of disturbances in cardiac rhythm.
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Explain charges in respect to the cardiac cell...
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...Inside the cardiac cell there is a net negative charge relative to the outside of the cell
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What is the Resting Membrane Potential (RMP)?
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The difference in the electronegative charge.
It results from an uneven distribution of ions (Na, K, Ca) across the cell membrane. |
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How is this distribution of ions maintained?
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An energy-requiring pump (the sodium-potassium ATPase pump) is needed.
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What is Action Potential?
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When a change in the distribution of ions causes cardiac cells to become excited.
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What does Action Potential do?
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The movement of ions across the cc's membrane results in the propagation of an electrical impulse.
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What is the result of Action Potential?
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This electrical impulse leads to contraction of the myocardial muscle.
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What is Action Potential?
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When a change in the distribution of ions causes cardiac cells to become excited.
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What is the Vaughan Williams Classification?
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A system commonly used to classify antidysrhythmic drugs.
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What does Action Potential do?
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The movement of ions across the cc's membrane results in the propagation of an electrical impulse.
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What is Class I?
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-Membrane-stabilizing agents
-Fast sodium channel blockers -Divided into Ia, Ib, and Ic agents, according to effects |
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What is an example of a class I and it's characteristics?
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Class I moricizine
-General Class I agent -Has characteristics of all three subclasses -Used for symptomatic ventricular and life-threatening dysrhythmias |
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What is an example of a class Ia and it's characteristics?
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Class Ia quinidine, procainamide, disopyramide
-Block sodium channels -DELAY repolarization -INCREASE the APD -Used for a-fib, premature atrial cont., premature vent. cont., v-tach, Wolff-Parkinson-White syndrome |
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What is an example of a class Ib and it's characteristics?
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Class Ib tocainide, mexiletine, phenoytoin, lidocaine
-Block sodium channels -ACCELERATE repolarization -DECREASE the APD -Used for ventricular dysrhythmias only |
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What is an example of a class Ic and it's characteristics?
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-Block sodium channels
-Little effect on APD repol. -Used for SEVERE vent. dysrhythmias -May be used in a-fib/flutter |
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Class II examples and effects
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Class II Beta blockers: atenolol, esmolol, petaprolol, propranolol
-Reduce or block sympathetic NS stim., reduce trans. of impulses -Depress phase 4 depolarization -General myocardial depressants for both supraventricular and vent. dys. |
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Class III examples and effects
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Class III amiodarone, dretylium, sotalol, ibutilide
-Increase APD -Prolong repolarization in phase 3 -Dysrhythmias that are difficult -Life-threatening v-tach or fib, a-fib/flutter - resistant to other drugs -Sustained v-tach |
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Class IV examples and effects
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-Calcium channel blockers
-Depress phase 4 depolarization -Paroxysmal supraventricular tach rate control for a-fib/flutter |
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Other Antidysrhythmics
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Digoxin, adenosine
-Have properties of several classes and aren't placed into one class |
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Digoxin does what...
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-Cardiac glycoside
-Inhibits Na-K ATPase pump - + inotrope, improves the strength of cardiac cont. |
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Digoxin (2)...
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-allows more Ca to be available for contraction
-Used for CHF and atrial dysrhythmias -Monitor K levels, drug levels, and for toxicity |
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adenosine (Adenocard)...
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-Slows conduction through the AV node
-Used to convert paroxysmal supraventricular tach to sinus rhythm -Very short half-life |
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adenosine (Adenocard) (2)...
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-Only administered as fast IV push
-May cause asystole for a few seconds -Other side effects minimal |
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ALL antidysrhythmics can cause dysthythmias!!!
Hypersensitivity rxns... |
...nausea
-vomiting -diarrhea -dizziness -blurred vision -headache |
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Antidysrhythmics:
Nursing implications |
-Obtain a thorough drug and medical history
-Measure baseline BP, P, I&O, and cardiac rhythm -Measure serum K level before initiating therapy |
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Antidysrhythmics:
Nursing Implications (2) |
-Assess for conditions that may be contraindications for use of specific agents
-Assess for potential drug interactions -Instruct patients regarding dosing sched. and side effect |
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Antidysrhythmics:
Nursing Implications (3) |
-During therapy monitor cardiac rhythm, HR, BP, well-being, color, temp, heart and breath sounds.
-Assess plasma drug levels -Class I - monitor ECG for QT intervals prolonged more than 50% |
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Antidysrhythmics:
Monitor for theraputic response... |
-DECREASED BP in hypertensive
-DECREASED edema -Regular PR or improved reg. |
