Arrhythmias Flashcards
What is AFib with RVR?
RVR = rapid ventricular rate
AFib with tachycardia over 100 bpm
Presenting symptoms for AFib
Dizziness, syncope
Palpitations
Dyspnea on exertion
Chest pain - esp if also have underlying structural disease
5 disease risk factors that predispose you to higher risk of developing AFib
- Mitral valve stenosis or prolapse
- Atria narrow as result of increased pressures - CAD
- HF - dilated heart causes increased pressures in LA –> stretch
- Hyperthyroidism
- HTN
When is the risk of stroke highest for AFib pts?
Right after you put them back into normal rhythm
Stagnant blood from AFib is now being moved with rhythm
What is the difference between valvular and non-valvular AFib?
Valvular - with mitral valve disease (stenosis or regurgitation)
Non-valvular - AFib without those
Why is CO reduced in AFib?
Answer = no atrial kick
+ fast HR (decreased filling time, lower SV with increased HR)
How much does atrial kick contribute to LV filling?
20%
What are the 2 therapeutic objectives you must do before restoring normal sinus rhythm in an AFib pt?
1st ALWAYS = anti-coag - warfarin, plavix, aspirin
2. Ventricular rate control
1st choice is BBs or Ca CBs
What is the goal HR for AFib pts?
110bpm
Studies show no benefit to lowering this further below
BB mechanism
B1 receptors blocked in heart
Trying to control the electrical activity through AV node
Ca channel blocker
Control rate at nodes b/c Ca channels are larger part of nodal AP
Non-DHP vs DHP use
Non = rate control DHP = HTN control
Goal for warfarin pts vs normal INR
Warfarin: 2=3
Normal: 1
Is there a difference between pharm methods of rate control
Chose based on structural heart disease vs no and what other drugs they’ve tried in the past and failed
- Prolonged QT
- Structural
- HF
Pharm methods to control rate
Look up on answer key!
Meds for long term AFib prevention
Propanolol = BBer Flecanide = class 1c, Na CB w/ no change AP Sotalol - class 3 (K CB) Amioderone - class 3 (K CB)
AFib pathophys
Multiple nodes of electrical impulse firing all at once
AFlutter pathophys
Looping re-entry
What is the CHADS scoring system to determine should you be on anti-coag therapy?
CHADS score Risk for stroke C - CHF H- HTN A - AGE D - diabetes Stroke (+2)
Triggers for AVNRT
Caffeine Exercise Smoking Stress Alcohol Increases the amt of pre-mature atrial contractions you can have -> the extra beat you need to set off AVNRT
Non-pharm, non-electrical acute treatment for AVNRT
Vagal stim: Valsalva Carotid massage Face in cold water Press eyeballs = pain stim for vagus
If you give adenosine and the arrhythmia terminates, what were the 2 possible causes of tachycardia?
Adenosine blocks excess tracts and lowers AV node rate
Adenosine stops AVNRT or AVRT
No rate conversion = AFib or flutter as cause of tachycardia
What would an AVRT pt have a totally normal EKG?
Ventricle to atria bypass tract
Only see AVRT when tachycardia - wide complex
Why don’t you give Ca CB or digoxin to WPW pts?
Both can enhance bypass tract conduction by shortening bypass refractory time Increased rate of arrhythmias Chose BBs or procainamide (class 1a)
Chronically treat AVNRT or AVRT pts with meds
Block AV node
BBs
Ca CBs
Pt with wide complex, regular tachycardia - p waves not consistently visible, QRS > 160 ms. What is the arrhythmia?
VT
1st line treatment for sustained VT + back up
Amioderone
2nd lidocaine
3rd procainamide
Cardioaversion vs defibrilation
Cardio - shocks pt on the QRS
Defrib - asynchronous, shock as soon as you press button regardless of where they are on their cardiac cycle, risk of putting them into a more unstable rhythm
Rapid, irregular rhythm + wide QRS complex with continuously changing amplitude - what is the arrhythmia
Torsades
Drugs for Torsades
Magnesium
Increase HR - isoproteronol
Torsades pathophys
EAD on T wave
“R on T phenomenon”
