Atrial
Fibrillation
Prediction
scores for AF post stroke
Rhythm control vs Rate Control
New Oral Anti-Coagulants (NOACs)
Definitions
•
‘First
detected’ then:
•
Paroxysmal
– Less than 7 days, spontaneously reverts
•
Persistent
– greater than 7 days but eventually self terminates or can be cardioverted
•
Permanent
– greater than one year and unable to convert to sinus rhythm (or cardioversion
has not been attempted)
•
Lone
AF - AF occurring without underlying heart disease
Causes
Cardiac Disease
·
MS, MR
·
HTN
·
IHD
·
Pericarditis
Non-Cardiac
·
Metabolic
o
Hyperthyroidism (1% of new onset
cases have clinical hyperthyroidism, 5% subclinical)
o
Low K+, Ca2+, Mg2+
o
Acidosis
o
Ethanol
o
Drugs – sympathomimetics
·
Respiratory
o
Pneumonia
o
PE
·
Other
Morbidity
associated with AF:
•
Embolism
•
Tachycardia
( Effect on haemodynamics)
•
Syncope
- due to pause on cessation of AF
•
Anxiety
- due to palpitations
•
Loss
of AV synchrony – reduced cardiac function
•
Overall
2x risk of death
Clincial
Signs:
•
Irregularly
irregular pulse
•
Tachycardia
•
Loss
of a waves in JVP
Investigations
•
Electrolytes
– K, Ca, Mg, HCO3
•
TFTs
•
±
Ethanol level
•
Echo
– valvular disease, assess atrial size
AF after Stroke
Prediction scores for
AF post stroke
Treatment
Rhythm control vs Rate Control
Predictors of recurrence
- Length of duration (>3months)
- CHF
- Structural heart disease
- HTN
- Inc. left atrial size
- Age >70
Evidence
AFFIRM and RACE studies
showed a trend towards initial rate control as the safest method
AFFIRM
- 4060 Patients
- >65 years OR have other risk factors for
stroke
- Either digoxin, B-blocker or Calcium channel vs Drug
therapy for rhythm control
- Warfarin for all in the rate group and at doctors
discretion in rhythm group
- 15% “failed rate control and tried rhythm control
- 38% failed rhythm control and tried rate control
- Trend towards reduced mortality in rate
group.
- Decrease in mortality in rate subgroups:
>65years and those without CHF.
- Subsequent analysis pointed to SE of
anti-arrhythmic drugs as main source of mortality difference.
- No significant difference in other outcomes
including stroke.
RACE
- 522 pts
- Persistent AF despite cardioversion
- Rate control as AFFIRM or rhythm control with sotolol then flecanide/propafennone then amiodarone.
- No difference in mortality at 2.3 years
- Trend towards lower incidence of composite
endpoint in rate group.
- Rhythm control significantly worse for patients
with HTN and women.
Rhythm Control versus Rate Control for Atrial Fibrillation and Heart
Failure Study
- NEJM 2008
- EF <35%
and symptoms of CHF
- Randomized to
standard rhythm or rate control
- No difference
between groups in any endpoint.
Suggested reasons for
initial rhythm control:
- Persistent symptoms
- Inability to attain rate control
- Patient preference
Rhythm control
Embolic risk during cardioversion
5-7% without
anticoagulation
1-2% with anticoagulation
Therefore either:
Within first 48hrs without anticoagulatuion (unless MS or hx of thromboembolic
disease)
Or INR >1.8 for 3 weeks
Or TOE to exclude thrombus
Should be anticoagulated
for 4 weeks post cardioversion
Electrical Cardioversion
-
70-90% effective
-
Definitely first line if
acute cardiovascular compromise
-
Start with 200J
Pharmocological Cardioversion
- Not as effective
- Can use:
Quinidine like agents
Flecanide (90% effective)
Amiodarone (65% effective).
Recurrence prevention
- Only 20-30% of patients
cardioverted maintain sinus for >1yr
- Drugs are not recommended
routinely after cardioversion unless frequent symptomatic recurrences
-If structural heart
disease
Amiodarone (if Heart
failure, mod/severe systolic dysfunction or HTN with LVH)
Sotolol
- If no structural heart
disease
Flecanide first choice
AF focus ablation therapy
-
Pulmonary vein isolation as
these have been found to be major site of AF initiation
-
Success rates are poorly
defined
-
Probably 70-80% in selected
patients
-
1-2% risk of major
complications.
-
Need for repeat procedures
common
-
Symptomatic relief is
currently the indication
-
Decreased stroke
risk/mortality has not been demonstrated.
Rate Control
- B-Blocker
- First line if no CI (e.g
poor LVF)
- Effective in acute episodes
- Effective during excercise
- Doses
- Ca Channel antagonist (non-dihydropyridine)
- As for B-blockers
- Digoxin
- NOT effective in acute episodes
- NOT effective in paroxysmal AF
- Not effective during exercise
- Useful if heart failure of hypotension
- Effective in Persistent AF
- Can be used in combination with above
- Amiodarone
- Can be used in patients with poor LVF
- Use limited by SE
- AV node ablation with pacemaker
Aims:
RACE II trial
·
Compared HR <110 vs
<80bpm
·
Found that <110 not
inferior therefore this is recommended target
Old guidelines
·
Rest HR <80
·
24hr holter
average <100, No HR > 110% of the age-predicted maximum
·
HR <110bpm in six min
walk
Anticoagulation/Antiplatelets
Incidence of stroke in
chronic AF:
- Average 3-5% per year without treatment
- Relative risk of stroke ~3fold
- 6% of AF emboli will be systemic
CHADS Score
|
|
|
CHADS2 Score |
CHA2DS2-VASc |
RR |
|
C |
CCF |
1 |
1 |
1.4 |
|
H |
Hypertension (included treated) |
1 |
1 |
1.6 |
|
A |
Age > 75 |
1 |
2 |
1.4 (per decade) |
|
D |
Diabetes |
1 |
1 |
1.7 |
|
S |
Previous
stroke or TIA |
2 |
2 |
2.5 |
|
V |
Vascular disease |
|
1 |
? |
|
A |
Age 65-74 |
|
1 |
|
|
S |
Sex - female |
|
1 |
? ~1.6 |
Score:
|
|
CHADS2 |
CHA2DS2-VASc |
|
|
Score |
Stroke rate (%/year) (95% CI) |
(%/year) |
|
|
1.9
(1.2–3.0) |
|||
|
2.8 (2.0–3.8) |
|||
|
4.0 (3.1–5.1) |
2.2 |
||
|
5.9 (4.6–7.3) |
|||
|
8.5 (6.3–11.1) |
4.0 |
||
|
12.5 (8.2–17.5) |
6.7 |
||
|
18.2 (10.5–27.4) |
9.8 |
||
|
7 |
|
|
9.6 |
|
8 |
|
|
6.7 |
|
9 |
|
|
15.2 |
HAS-BLED
|
|
Risk Factor |
Points |
|
H |
Hypertension |
1 |
|
A |
Abnormal renal
and/or liver function |
1 or 2 |
|
S |
Stroke |
1 |
|
B |
Bleeding |
1 |
|
L |
Labile INR |
1 |
|
E |
Elderly (>65) |
1 |
|
D |
Drug therapy
(Aspirin/NSAID/Steroid) or alcohol misuse |
1 or 2 |
|
HAS-BLED Score (No. of patients) |
Bleeds/100patient years |
|
0 (798) |
1.13 |
|
1 (1286) |
1.02 |
|
2 (744) |
1.88 |
|
3 (187) |
3.74 |
|
4 (46) |
8.70 |
|
5 (8) |
12.50 |
|
6 (2) |
0 |
|
7 (0) |
- |
|
8 (0) |
- |
|
9 (0) |
- |
Warfarin
•
62% RR reduction in stroke risk
•
Twice
the haemorrhage risk of aspirin
•
Risk
of major bleeding average 1-1.5% per year
o
This
is from trial data where warfarin use was well controlled, probably higher in reality.
Aspirin
•
22% reduction of stroke risk
•
BAFTA
trial 2007
o
Patients
older than 75yrs, aspirin vs Warfarin
o
Stroke,
embolism, intracranial haemorrhage 1.8% vs 3.5%
(warfarin vs aspirin), HR0.75
o
No
difference in major haemorrhage
Aspirin plus Clopidogrel
• Inferior to Warfarin (ACTIVE W trial – RRR with
warfarin 42%)
• Probably better than aspirin alone (ACTIVE A trial)
o
Decreased risk of
stroke 0.72 (2.4% vs 3.3% - ARR 0.9% - NNT 111)
o
Increased major
bleeding 1.57 (2.0% vs1.3% - ARI 0.7% -
NNH 143)
o
Therefore for
1000 people treated 2 have net benefit
o
Trial was for
people unable or unwilling to take warfarin.
If people with high bleeding risk are excluded then benefit probably
higher.
New Oral Anti-Coagulants (NOACs)
See NOACs