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Flashcards in 21 - Atrial Fibrillation Deck (56)
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1

What are the different classifications of atrial fibrillation?

- Paroxysmal AF
- Persistent AF
- Long standing persistent AF
- Lone AF

2

What is paroxysmal AF?

- episodes may last 1-7 days

3

What is persistent AF?

not self-limited; lasts for longer than 7 days

4

What is long standing persistent AF?

lasts over a year

5

What is lone AF?

Used less often; young, low risk, CHADS2=0 (qv)
Don’t know why they have it and they’re young

6

What pathophysiological elements will you see in atrial fibrillation patients?

- Atrial enlargement (wall stretch)
- Ischemia
- Toxins
- Metabolic disease
- Hemodynamic impairment

7

Describe the atrial wall enlargement

- Can be due to mitral valve disease or rheumatic heart disease
- Wall stretch – start to break apart the conduction fibers in the atria due to increased pressure

8

Describe toxins that can cause atrial fibrillation

ALCOHOL = classic example
- Holiday heart symptoms because they went on a “bender” over the holidays and it is causing heart symptoms
- Direct cardiac toxin

9

What type of metabolic disease can send a patient into AF?

- Hyperthyroid

10

What type of hemotynamic impairment results from AF?

- Loss of atrial addition to the systolic volume
- Tachyarrhythmia

11

Describe the cardiomyopathy seen in AF

- Dilated cardiomyopathy
- Will see dilation in the left atrium and left ventricle
- The size of LA and LV will be increased in size

12

What types of things will you ask in the history for an AF workup?

- hypertension
- rheumatic heart disease
- valvular heart disease
- myocardial ischemia/ infarction (CAD)
- alcoholism
- palpitations
- symptoms of heart failure (SOB, PND, etc.)
- thyroid disease
- stroke

13

What types of things will you look for in the physical exam?

- “irregularly irregular” pulse
- variable intensity S1 (softer with long cycles)
- heart murmur (e.g. MR/MS)
- pulmonary rales/rhonchi
- hepatic edema (enlarged liver)
- peripheral edema

14

Why will S1 vary in intensity? Why will the mitral valve closure sound different?

Why will S1 vary? Why will mitral valve closure sound different?
- Varying levels of blood
- Varying stroke volume
- Some have more time to fill, some have less
- Mitral regurgitation – the base of the valve (circle) widens but the valves themselves do not get larger, so they pull apart

15

What will you do for lab tests?

Chest x-ray
- may suggest heart failure:
- pulmonary congestion
- cardiac enlargement

Lab tests
- may relate to myocardial ischemia (e.g. troponin)
- may relate to toxic/metabolic disease (e.g. thyroid fnx)
- no findings in “lone” Afib

Echocardiography

16

What are you looking for in echocardiography?

This is CRUCIAL

Looking for...
- Valvular disease
- Chamber enlargement
- Intracardiac thrombi

17

What is the main consequence of AF?

***Thromboembolism***

18

What are other consequences of AF?

- Thrombi can be present in Left Atrium
- Nonvalvular AF most common (~50%)
- Stroke (low risk in lone AF)
- Diminished cardiac output
- Ischemic events
- Exercise capacity diminished (HR does not respond to demand)

19

Why does the heart not respond to increased demand in cases of AF?

Loss of vagal and adrenergic chronotropic influences

20

What are causes of AF that are not due to pathology in the heart valves?

- Age >65 
- Hypertension
- Rheumatic heart disease (also valvular)
- Prior stroke or transient ischemic attack 
- Diabetes mellitus 
- Congestive heart failure 

21

What are the treatment goals in atrial fibrillation?

Rhythm and rate control

You can either try to control the rhythm (get them back in to normal sinus rhythm) or you can try to get control over the rate

22

Describe the goal of rhythm control

Rhythm control: restore/maintain sinus rhythm, may
- improve symptoms
- improve hemodynamics
- reduce stroke risk
- avoid anticoagulation

23

Describe the goal of rate control

maintain acceptable ventricular rate in chronic AFib

24

Describe the treatment of AF in terms of what is better - rate or rhythm control?

- No survival advantage with either strategy
- Rhythm control patients hospitalized more for adverse drug problems
- Stroke risk similar between groups

According to AFFIRM study

25

What did a different test say about mortality rates?

Rhythm control may be lightly more effective than rate control, but it is not a significant difference, can be due to chance

26

In which patients would you try to first control the rhythm?

Rhythm control: restore/maintain NSR
- Most common to try on your patient who wants great quality of life and minimal risk – younger patients

27

In which patients would you try to first control the rate?

Rate control: maintain acceptable ventricular rate in chronic AF
- Most common overall
- Most common in elderly procedure

28

What is the main goal in all patients?

Avoid embolic events!!!

29

Describe the process of rhythm control (younger, healthy)

- DC conversion to NSR usually preferred (v. drug tx) - shock the patient into normal sinus rhythm

Urgent DC cardioversion needed if:
- current myocardial ischemia
- evidence of hypoperfusion
- severe heart failure symptoms
- pre-excitation present

Infrequent episodes that don’t convert spontaneously

30

What do you do if shocking the patient into NSR doesn't work?

Pharmacologic treatment
- Not as successful
- Not primary choice