Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
28 Cards in this Set
- Front
- Back
|
What is the aim of electrical therapy for dysrhthmias? |
To depolarize all the myocardial cells at once in an attempt to restart the heart in a regular rhythm |
|
|
How does Atropine work? |
inhibits the vagus nerve, so atropine "takes your foot off the brake" |
|
|
Symptomatic Bradycardia treatment |
Atropine 0.5mg IV or IO repeated every 3-5 minutes, up to 3mg. Transcutaneous pacing (consider sedation) Dopamine or Epi infusions as pressors |
|
|
Why do we give Dopamine to symptomatic bradycardia? |
At high doses (more than 10 mcg/kg/min), dopamine acts as an alpha stimulator, which increases systemic vascular resistance and increases BP. |
|
|
What class is Atropine? |
An anticholinergic that competes with Ach at the muscarinic receptor. |
|
|
How does Adenosine work? |
alters the movement of potassium in the action potential of the heart, which slows the conduction through the SA node. |
|
|
Can you use Adenosine for ventricular dysrhythmias? |
No- it slows conduction through the SA node, so it can only be given for atrial dysrhythmias that are tachycardic. |
|
|
How do calcium channel blockers work? |
They block the influx of calcium into the cardiac cells and arterial smooth muscle cells. This slows the conduction velocity of the action potential and prolongs repolarization. The overall effect is that the impulses through the AV node are slowed, which slows the ventricular rate. |
|
|
When you give a calcium channel blocker, you need to be aware of what side effect: |
Hypotension because some calcium channel blockers cause arteriole dilation. |
|
|
Why do we give calcium channel blockers for A-fib or A-flutter? |
Because they do not convert these rhythms to a normal sinus rhythm (which can be dangerous due to blood clot formation) but instead, they slow down the ventricular rate by slowing conduction through the AV node. |
|
|
Why are calcium channel blockers sometimes used to treat angina and migraines? |
They block vasospasm |
|
|
What are calcium channel blockers used to treat? |
Angina, Migraine headaches, SVT, A-fib, A-flutter, junctional, ectopic, or multifocal tachycardias that can't be controlled by adenosine or vagal maneuvers, HTN |
|
|
What is Diltiazem used to treat? |
Ventricular rate control in rapid A-fib |
|
|
What are the contraindications to Diltiazem? |
-Heart Blocks because Diltizem causes a slower HR -Heart Failure because it causes a decreased HR which would decrease CO in someone in heart failure. -Hypotension because Diltizem can cause arteriole dilation which causes hypotension. |
|
|
What is Diltiazem's dose? |
0.25mg/kg IV or IO over 2 minutes |
|
|
Who would you be extremely cautious in giving a calcium channel blocker to? |
Someone already taking beta blockers |
|
|
Verapamil Contraindications |
-2nd or 3rd degree AV block (slows HR) -Hypotension (causes hypotension) -Cardiogenic shock (will decrease CO) -Sick Sinus Syndrome (can interfere with sinus node conduction) -Wolff-Parkinson White syndrome (can interfere with sinus node conduction in accessory pathway dysrhythmias) -Severe Left Ventricular dysfunction -Hypersensitivity |
|
|
Why is Verapamil contraindicated for Sick-Sinus Syndrome? |
It can interfere in sinus node conduction in patients with sick-sinus syndrome and can cause SA node blocks or sinus arrest. |
|
|
Name the contraindications for beta blockers and why they are contraindicated. |
-Heart Failure- Beta blockers decrease HR which would decrease CO in pts with heart failure -AV blocks- would decrease HR even further than it is already decreased -Bradycardia- will decrease HR further -Asthma/restrictive airway disease- albuterol will be ineffective if they have an asthma attack |
|
|
What are Amiodarone's contraindications? |
-Sick-Sinus Syndrome- can cause heart blocks and sinus arrest -2nd and 3rd degree Heart Blocks-slows conduction so it would make it worse -Cardiogenic shock- decreases HR -Hypersensitivity -Bradycardia that has caused syncope- can make them more brady, and can cause hypotension |
|
|
Describe Amiodarone's effects and how it works |
Delay in repolarization, prolongation of the action potential, slow of electrical conduction speed, reduction in the firing by the SA node, and slowing in conduction of through accessory pathways. Can also cause vasodilation which can cause hypotension |
|
|
What kind of antiarrhythmic is amiodarone? |
Mainly a potassium channel blocker, but has the effects of sodium channel blockers, beta blockers, and calcium channel blockers.
|
|
|
What are the effects of sodium channel blockers? |
Decreases the slope of Phase 0 of the cardiac action potential, by delaying how quickly the sodium flows into the cell. Can suppress abnormal conduction by decreasing the slope of Phase 4. Negative Inotropy |
|
|
What are the common contraindications for Sodium Channel blockers? |
-Torsades- due to the delaying of the action potential, it can cause or worsen Torsades. -AV blocks- decreases HR -QT prolongation- can cause Torsades
|
|
|
How does Mag Sulfate help Torsades? |
Treats PVCs caused by a long QT interval. May block sodium channels but the mechanism is not really known. Can treat dysrhythmias caused by treating hypomagnesia |
|
|
Drug of choice for ventricular dysrhythmias? |
Amiodarone |
|
|
What is the effect of atropine on a bradycardic patient? |
Takes the foot off the brake |
|
|
Two meds indicated for PEA and Asystole? (according to the book) |
Epi and Vasopressin |
