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Flashcards in Atrial Fibrillation Deck (23):
1

Atrial Fibrillation

Irregularly Irregular

Multiple ectopic atrial foci produce fibrillation waves

Atria do not contract,
Beware of CLOTS!!! (common in the appendages-- procedures like the lariat and the watchman can close these off or exclude them)

AV node gates entry to the ventricles

The most common cardiac arrhythmia
The RR interval follows no repetitive pattern
No distinct “P” waves, undulation of the baseline, atrial rate 300-600 beats/minute

2

Atrial Fibrillation with Rapid Ventricular Response

CAD, Valvular heart disease, Pulmonary disease, Hyperthyroidism
Can be temporary in normal individual
- Exercise
- EtOH

f waves in fibrillation
F waves in Flutter

3

when you raise heart rate, which time interval is most affected?

diastole

you decrease filling rate --> decreased stroke volume

4

atrial contribution to ventricular filling-- what heart sound?

S4

5

What should S3 in adults make you think of?

heart failure

6

what percent of the ventricular filling comes from the atrial kick in people without heart failure?

5% or less, you wouldn't notice it being gone

but in heart failure it can be as much as 40%

7

AF - who gets it?

More common in men
Increases with age
AF reduces cardiac output by decreasing filling from increased rate encroaching on diastolic filling time and loss of atrial contribution to ventricular filling

8

AF Etiology

1. Hypertensive Heart Disease
2. CHD
3. RF in underdeveloped countries
4. Hyperthyroidism- drives the heart nuts (palpitations)
5. Genetic (likely most common)

9

underlying details of AF

Changes in the refractory period of the underlying atrial musculature
PAC (APBs) often precipitate atrial fib of all kinds
AF may be valvular or non-valvular

10

treating AF

Always address underlying cause
ie; postop cardiac surgery, hyperthyroidism, mitral valve disease, pulmonary disease, etc.

11

AF Classification

1. Paroxysmal-AF that terminates spontaneously or with intervention within 7 days of onset. Episodes may recur with variable frequency.

2. Persistent-AF that fails to self-terminate within 7 days. Episodes often require pharmacologic or electrical cardioversion to restore NSR (Normal Sinus Rhythm). AF generally progresses.

3. Long standing persistent-AF that has lasted for more than 12 months.

Permanent AF- patients with persistent AF where a joint decision has been made by the patient and clinician to no longer pursue a rhythm control strategy.

12

Low Risk AF

Used to be called “Lone” AF.
15-30% of AF
Younger male patients
Frequently familial, low risk of thrombo-embolus (CHA2DS2-VASc score of 0).

13

Recurrent AF

90% of AF patients have asymptomatic recurrent episodes lasting up to 48 hours

14

Subclinical AF

AF detected in asymptomatic patients without a prior diagnosis. Many of these patients have paroxysmal AF.

15

Evaluation of the Patient 1. H&P

History of palps, syncope, dyspnea, fatigue. Precipitating causes include exercise, emotion, alcohol- Holiday Heart.
PE-mitral valve disease, especially MS, CHF findings, etc.

16

Anti Coagulation: CHA2DS2-VASc:

This is becoming the most useful tool for deciding risk of stroke to determine whether to anti-coagulate

C=Congestive Heart Failure
H=Hypertension
A2=Age>=75 (2 points)
D=Diabetes Mellitus
S2=Stroke, TIA or Thromboembolus (2 points)
V=Vascular Disease (prior MI, PAD, aortic plaque)
A=Age (65-74) 1 point
Sc= Sex category, Female (1 point)

17

CHA2DS2-VASc score and stroke risk/year

Score Risk
0 0.2%
1 0.6%
2 2.2%
3 3.2%
4 4.8%
5 7.2%
6 9.7%
7 11.2%
8 10.8%
9 12.2%

18

when do you anticoagulate for sure?

absolutely at 2 points, consider at 1

19

Warfarin

1954 FDA approval
“WARF”=Wisconsin Alumni Research Foundation
Derived from “sweet clover animal feed” spoiled with a fungus, discovered at the University of Wisconsin.

First oral anti coagulant
Measured by INR (International Normalized Ratio)
Therapeutic range 2.0-3.0 for atrial fibrillation stroke prevention

20

AF Anticoagulants

NOAC (Novel Oral Anti Coagulants) are replacing warfarin in many patients
No blood testing necessary
These drugs interfere very little with other drugs and virtually no foods
As of this date there are 3 available
One Direct Thrombin Inhibitor, Pradaxa, dabigitran

21

NOAC

2 Factor Xa inhibitors
Xarelto (rivaroxaban)
Eliquis (apixaban)

22

Evaluation

EKG-rhythm, rate, other abnormal findings, LVH, ST changes, QRS width, QT interval, PR interval.
Echocardiogram-chamber sizes and function, valvular function, pulmonary artery pressures (Pulmonary Hypertension).

23

Treatment, Tale of 2 Cities

1. Rate Control- patient is appropriately anti-coagulated and the rate is controlled by AV blockers.
2. Rhythm Control- effort is made to anti-coagulate and restore NSR by meds or electrical cardioversion. A TEE may be used to rule out LA thrombus prior to cardioversion.