A Fib Lecture Flashcards
(77 cards)
1
Q
A Fib is the loss of what
A
atrial contractility
2
Q
Afib results in what?
A
irregular ventricular response
rapid heart rate
3
Q
what is the HR with A fib
A
120-160
4
Q
what can A fib lead to
A
clot formation and subsequent thromboembolic events (leading cause of stroke)
5
Q
what is the most common sustained arrhythmia
A
A fib
6
Q
what populations does A fib affect most
A
risk increases with age >65
men >women
whites > blacks, hispanics, asians
7
Q
etiologies of atrial fibrillation
A
- acute hyperthyroidism
- acute vagotonic episode
- acute alcohol intoxication
- post operatively after major surgery
- atrial enlargement
- disruption of electrical conduction system (scarring or infiltration)
8
Q
pathophys of afib
A
elevation in atrial pressure
majority of episodes of PAF are triggered by atrial premature beats
can be triggered by other supraventricular arrhythmia: atrial flutter or atrial tachycardia
9
Q
what is A Fib
A
disorganized rapid and irregular atrial activation
10
Q
ectopic foci in afib are most often located where
A
ostial portion of pulmonary veins (site of ablation)
11
Q
risk factors for Afib
A
- age >64
- male
- HTN
- elevated BMI
- PR interval prolonged
- valvular dz
- CHF
12
Q
classifications of Afib
A
- paroxysmal - intermittent
- persistent - fails to self terminate within 7 days and requires intervention in order to convert
- permanent - >12 months & no longer pursue rhythm control
- Lone AF - without structural heart dz, lowest risk of complications (term not used much anymore)
13
Q
Dz associations with Afib
A
- valvular heart dz (significant stenosis or regurgitation; rheumatic heart dz)
- heart failure
- HTN heart dz
- acute myocardial infarction (probably due to atrial ischemia or stretch)
14
Q
symptoms of afib
A
- asymptomatic
- heart palpitations
- light headedness, pre syncope, syncope
- SOB and exercise tolerance
- chest pain - rare unless concomittant CAD
- fatigue
15
Q
common triggers of afib episodes
A
sleep deprivation physical illness post surgery stress hyperthyroidism physical exertion/exercise stimulant medications alcohol caffeine dehydration
16
Q
initial presentation of new onset of a fib
A
heart palpitations fatigue or lightheadedness SOB angina incidental
17
Q
what do you want to control in new onset of afib
A
- rate and rhythm control
2. prevention of systemic emboli
18
Q
diagnostic studies for afib
A
EKG
echo
stress test
labs: CBC, BMP, TSH
19
Q
history taking for afib
A
symptoms: onset, frequency, duration, quality, severity (tachy and fatigue)
precipitating causes (alcohol, exercise)
underlying dz:
CAD, CHF, CVA/TIA, DM, HTN, COPD, thyroid disorder
20
Q
phyiscal exam in afib
A
complete cardiovascular exam
- BP and pulse
- murmurs
- evidence of heart failure (JVP etc)
- extremity pulses
21
Q
EKG for Afib
A
needed to make the diagnosis -LVH -pathologic Q waves delta waves, short PR interval QT interval duration
22
Q
echo for afib
A
size of atria size and functino of R/L ventricles valvular heart dz pericardial dz atrial thombus**low sensitivity
23
Q
TEE for afib
A
transesophageal echocardiogram
far more sensitive for detecting atrial thrombus
-prior to cardio conversion
-could throw a clot
24
Q
when to do exercise stress test with afib
A
assess for ischemic heart dz
25
differences of ST segments bw ischemia and MI
ischemia - ST segment depressed in ischemia (no death of tissue yet, just not being perfused)
MI - ST elevation
26
why give pt home heart monitors?
to determine if persistent or paroxysmal
27
lab testing for afib
TSH - all patients with first episode of afib or incr frequency
CBC
chemistries/electrolytes (incld kidney function tests)
28
4 goals for afib
1. rhythm control (if not yet permanent)
2. reduce the risk of stroke and other peripheral emboli (prevention of systemic embolization)
3. prevent tachycardia mediated cardiomyopthy and ischemia (rate control)
4. alleviate symptoms (usually d/t increased HR)
29
management decisions for new afib
is cardioversion indicated and should it be urgent?
does the pt need rate control
does the pt need to be anticoagulated for emobolization prevention
does the pt need to be hospitalized
are tehre correctable causes of afib (drugs)
30
possible indications for urgent direct current cardioversion
1. active ischemia
2. unstable hemodynamics
3. evidence of organ hypoperfusion
4. severe manifestations of heart failure (pulm edema)
5. the presence of WPW
* *risks and benefits of cardioversion must be weighed carefully
31
indications for nonurgent DC cardioversion
new onset or newly recognized atrial fibrillation
| pts with persistent AF who are limited by their symptoms
32
reasons not to cardioconvert in afib
1. known afib and minimally symptomatic
2. multiple comorbities
3. unlikely to maintain NSR
4. benefits of cardioversion decrease after 80yo
5. paroxysmal AF (go in and out on their own)
33
what do you give a pt prior to cardioversion
IV heparin
| control ventricular RATE
34
what happens in afib duration >48hrs
hold off bc its too risky to do cardioversion d/t clot, need full anticoags (3weeks) and do transesophageal echo to look for clot
35
afib with rapid ventricular response can reach what bpm
>150
36
complications of rapid afib
symptoms - fatigue, chest pain
ischemia
pulm edema
tachycardia induced cardiomyopathy (LV dilation, cellular morphologic changes)
37
4 classes of pharm tx of afib
1. beta blockers
2. calcium channel blockers
3. digoxin
4. amiodarone
38
beta blockers for tx of rapid afib
1. immediate control: IV metoprolol start at 5mg IVP can give 2nd dose of 5mg if first didnt work or if it wears off
2. long term control: oral metoprolol (tartrate: short acting: every 6hrs OR succinate: long acting: 1/day)
39
what beta blockers would be used in afib with the following comorbidities?
1. liver failure
2. heart failure
1. nadolol
| 2. carvediolol
40
what beta blocker is better for BP but can also be used to try and treat rapid afib
atenolol
41
calcium channel blockers for rapid afib
1. immediate control: IV diltiazem (5-10mg IVP); can also do a Dilt drip: continuous infusion that is titrated up until target HR reached
2. oral diltiazem - 3/day for short acting or 1/day for long acting
42
digoxin for rapid afib
can be IV or oral
-less effective for rate control particularly during exercise
can be added to beta blockers if insufficient or intolerant
-initial dose is loading dose (higher) then daily maintenance dose
-plasma digoxin levels should be monitored periodically d/t risk of dig toxicity
43
amiodarone for afib
- maintains sinus rhythm in AF pts (antiarrhythmic)
- can also slow rate for refractory afib with RBR after maximizing BB and CCB
- immediate use: IV
- long term maintenance: oral
- less likely to cause hypotension
- SEs: abnormal LFTs, pulm toxicity (months to years after initiation so dont use long term), chronic interstitial pneumonitis (scarring thruout lungs = restrictive dz)
44
arterial embolization from atrial fibrillation
risk 0.5% per year to 6.9% per year
- stasis of atrial blood leads to clot formation
- especially in left atrial appendage (LAA)
- ischemic stroke is the most frequent
- can occur at any point in time
- valvular heart dz increased risk
45
what scoring system is used to assess pts need to be on anticoagulants with afib
CHADS2 score
0: no anticoags
1-2: consider next scoring system
>=3: high risk, def need anticoags
46
what scoring system do you use if CHADS2 score is 1-2 (intermediate)
CHA2DS2 VASc model
pts with a score >=2 are recommended to have long term anticoagulation
47
what factors does the CHADS2 system use
HTN = 1pt
Age >75 = 1pt
DM = 1pt
prior stroke/TIA = 2pts**
48
what factors does CHADS2-VASc model use
```
age 65-74 = 1
age >=75 = 2
female = 1
CHF = 1
HTN = 1
Stroke/TIA = 2
vascular dz = 1
DM = 1
```
49
warfarin for anticoag for afib
- how often is it used?
- how effective?
- cost?
- downside
```
most commonly used
effective
inexpensive
significant risk of bleeding
frequent blood draws
```
50
how does warfarin work?
competively depletes functional vit K reserves and hence reduces synthesis of many active clotting factors
51
how to reverse warfarin
administer vitK
52
how long does warfarin take to start working
24-72hrs
53
full therapeutic effect starts when on warfarin
5-7 days
54
how is warfarin monitored
INR - 2.5 goal
55
how is warfarin metabolized
hepatically via CYP2C9 = lots of DI's
56
what options can you use for anticoag for immediate use
IV heparin or lovanox
57
when to bridge warfarin with heparin or LMWH in pts with afib
not usually necessary
recent or ongoing stroke or other embolus
known arterial thrombus
currently hospitalized (bc its easy)
58
warfarin compared to newer agents
```
-newer anticoags:
direct thrombin and factor Xa inhibitors
similar or lower rates of ischemic stroke
similar or lower rates of major bleeding
do not require frequent lab draw
EXPENSIVE**
```
59
indications for hospitalization for afib
immediate anticoagulation (bridge)
ablation of accessory pathway (WPW)
tx of associated medical problem that may trigger afib (infection, COPD, CHF)
management of rate or sick sinus syndrome
60
is afib common?
yes
61
what does afib put the pt at risk for
stroke and other embolic events
62
goals of afib
management of symptoms, rate vs rhythm control, and stroke prevention
63
occurence of aflutter vs afib
less common than afib
64
aflutter sometimes leads to
afib
65
aflutter commonly occurs after
initiation of an antiarrhythmic drug for afib
66
aflutter is associated with what
Left atrial enlargement
67
what are the rates like in aflutter
```
rapid ventricular rate (150bpm)
atrial rate (250-350bpm) - f waves
```
68
associated disorders with aflutter
1. hyperthyroidism
2. heart failure
3. obesity
4. obstructive sleep apnea
5. sick sinus syndrome
6. pericarditis
7. pulm dz
8. pulm embolism
69
clinical manifestations of aflutter
```
palpitations
lightheaded
SOB
tachycardia
evidence of CHF
```
70
diagnostic studies for aflutter
EKG
echo
TEE
exercise stress test
71
complications of aflutter
cardiac ischemia
pulmonary edema
tachycardia induced cardiomyopathy
thromboembolism
72
treatment considerations in aflutter
control ventricular rate
convert to NSR
maintain NSR
prevent systemic embolization
73
rate control in aflutter
more difficult than afib
use BB or CCB (digoxin can be added)
amiodarone is rarely used
radiofrequency catheter ablation
74
what is radiofrequency catheter ablation
type 1 aflutter
large macroreentrant pathway in right atrium involving obligatory pathway bw inferior vena cava and the tricuspid annulus
ablation of IVC-TA area
maintains sinus rhythm after procedure
65-100% success rate
7-44% have recurrent atrial arrhythmia, usually afib
75
pharm therapy for conversion to NSR
only 20-30% effective at maintaing NSR
- dronedarone
- flecainide
- sotalol
- dofetilide
- amiodarone
76
anticoagulation for aflutter
- prior to RF catheter ablation - 4 weeks or consider TEE
- after RF catheter ablation - anticoagulation x 1month
- recurrent aflutter or afib after ablation plan indefinite anticoagulation if CHADS2 score >=1
77
aflutter pts at risk for
strok and other embolism
