Atrial Fibrillation - كلية الطب · or high risk atrial fibrillation patients (CHA2DS2-VASc...
Transcript of Atrial Fibrillation - كلية الطب · or high risk atrial fibrillation patients (CHA2DS2-VASc...
Atrial Fibrillation
Dr. Jamal Dabbas Interventional cardiologist & internist
Some types of arrhythmia
• Supraventricular • Sinus Nodal
– Sinus bradycardia – Sinus tachycardia – Sinus arrhythmia
• Atrial – Atrial tachycardia – Atrial flutter – Atrial fibrillation
• AV Nodal – AVNSVT – Heart blocks
• Junctional • Ventricular
– Escape rhythms – Ventricular tachycardia – Ventricular fibrillation
Atrial fibrillation
• A heart rhythm disorder (arrhythmia). It usually involves a rapid heart rate, in which the upper heart chambers (atria) are stimulated to contract in a very disorganized and abnormal manner.
• A type of supraventricular tachyarrhythmia
• The most common arrhythmia
Aetiology
• Rheumatic heart disease
• Coronary heart disease (MI)
• Hypertension
• Myopericarditis
• Hypertrophic cardiomyopathy
• Cardiac surgery
• Thyrotoxicosis
• Infection
• Alcohol abuse
• Pulmonary embolism
• Caffeine
• Exercise
• Lone AF
Classification
• New / Recent onset
– < 48 hours
• Paroxysmal
– variable duration
– self terminating
• Persistent
– Non-self terminating
– Cardiovertable
• Permanent
– Non-self terminating
– Non-cardiovertable
Symptoms / Signs
• Breathlessness / dyspnoea
• Palpitations
• Syncope / dizziness
• Chest discomfort
• Stroke / TIA – 6 x risk of CVA
– 2 x risk of death
– 18 x risk of CVA if rheumatic heart disease
• Irregularly irregular pulse – Atrial rate
• 300-600bpm
– Ventricular rate depends on degree of AV block
• 120-160bpm
• Peripheral rate slower (pulse deficit)
Investigations
• Electrocardiogram (ECG) – All patients
– May need ambulatory monitoring
• Transthoracic echocardiogram (TTE) – Establish baseline
– Identify structural heart disease
– Risk stratification for anti-thrombotic therapy
• Transoesophogeal echocardiography (TOE) – Further valve assessment
– If TTE inconclusive / difficult
Normal Sinus Rhythm
‘Fast’ AF
‘Slow’ AF
Investigations
Electrocardiogram (ECG)
All patients
May need ambulatory monitoring
Transthoracic echocardiogram (TTE)
Baseline
Structural heart disease
Risk stratification for anti-thrombotic therapy
Transoesophogeal echocardiography (TOE)
Further valve assessment
TTE inconclusive / difficult
Diagnosis
• Based on:
– ECG
– Presentation
– Response to treatment
Treatment objectives
• Rhythm / rate control
• Stroke prevention
Treatment strategies
• New / Recent onset
– Cardioversion
– Rhythm control
• Paroxysmal
– Rate control or cardioversion during paroxysm
– Rhythm control if needed
• Persistent
– Cardioversion
– Rhythm control
– Peri-cardioversion thromboprophylaxis
• Permanent
– Rate control
– Thromboprophylaxis
Pharmacological Options
• Class Ic Anti-arrhythmics
– Flecainide / Propafenone
– Rhythm control
– May also be pro-arrhythmic
• Class II Anti-arrhythmics
– Beta-blockers
– Mainly rate control
– Control rate during exercise and at rest
– Generally first choice
– Choice depends on co-morbidities
• Class III Anti-arryhthmics – Amiodarone / Dronedarone
– Mainly rhythm control
– May be pro-arrhythmic
– Concerns over toxicity
• Class IV Anti-arryhthmics – Calcium channel blockers (verapamil / diltiazem only)
– Rate control only
– Alternative to beta-blockers if no heart failure
• Digoxin – Rate control only
– Does not control rate during exercise
– Third choice unless others contra-indicated
Acute AF
Treatment will depend on:
• History of AF
• Time to presentation (<> 24 hours)
• Co-morbidities (CHD, CHF/LVSD etc)
• Likelihood of success (History)
• Rate Vs. Rhythm control
• Rhythm control not feasible or safe – Beta-blocker – Verapamil – Digoxin (CHF)
• Rhythm control if possible and safe – DC cardioversion (if possible) – Amiodarone (CHD or CHF/LVSD) – Flecainide (Paroxysmal AF)
Paroxymal AF
• Rhythm control*
– Beta-blocker
– Class 1c agent or sotalol
• If CHD - sotalol
• If LVD: Amiodarone
– Dronedarone?
• Not if heart failure
*May be “Pill in the pocket”
• Antithrombotic therapy as per risk assessment
– Aspirin 75-300mg
– warfarin to INR 2-3
• See later
Persistent AF
• Rhythm control – Beta blocker – No structural heart
disease: Class 1c* or sotalol
– Structural heart disease: amiodarone
• Rate control
– As for permanent AF
* not if CHD present
• Antithrombotic therapy as per risk assessment
• Pre-cardioversion thromboprophylaxis of at least 3 weeks
• If rate control, as for permanent AF
Permanent AF
• Beta blocker or
• Calcium channel blocker and/or
• Digoxin
• Amiodarone?
– Option if poor rate control on above
• Dronedarone?
– Increased mortality
• Antithrombotic therapy as per risk assessment
– Aspirin 75-300mg
– Warfarin to INR 2-3
• See later
Stroke Risk Assessment (CHADS2)
• C Chronic Heart Failure (1 point)
• H Hypertension (1 point)
• A Age > 75 years (1 point)
• D Diabetes (1 point)
• S Stroke, TIA or systemic embolisation (2 points)
• Score < 2: low risk, aspirin* or anticoagulant
• Score ≥ 2: high risk, anticoagulant indicated
*Evidence for aspirin is weak
Stroke Risk Assessment (CHA2DS2VASc)
• Alternative to CHADS2
• C Chronic Heart Failure (1 point)
• H Hypertension (1 point)
• A Age > 75 years (2 points)
• D Diabetes (1 point)
• S Stroke, TIA or systemic embolisation (2 points)
• V vascular disease (1 point)
• A Age 65-74 years (1 point)
• Sc Sex category (1 point if female)
• Score ≥2 = High risk – anticoagulate unless contraindicated
Bleeding Risk Assessment (HAS-BLED)
• 1 point each for: – Hypertension
– Abnormal renal/liver function (1 for each)
– Stroke
– Bleeding history or predisposition
– Labile INR
– Elderly (age over 65)
– Drugs*/alcohol** concomitantly (1 for each)
*Drugs that increase bleeding, e.g. aspirin
** Alcohol excess
Anticoagulants
• Warfarin remains standard anticoagulant at present
• 3 new oral anticoagulants – Dabigatran (Direct thrombin inhibitor)
• Licensed by MHRA • Approved by SMC
– Rivaroxiban (Factor Xa inhibitor) • Licensed by MHRA
– Apixaban (Factor Xa inhibitor)
• Fixed doses • No monitoring • At least as effective as warfarin • Safer than warfarin? • Dabigatran capsules not stable outside of original blister • Very difficult to reverse effect unlike warfarin • Much more expensive (even allowing for INR costs) • Place in therapy not clear yet
Dabigatran Consensus
NHS in Healthcare Improvement Scotland Working Group: National consensus on dabigatran
The consensus statement states that: • on balance of risks and benefits, warfarin remains the anticoagulant of clinical choice for moderate
or high risk atrial fibrillation patients (CHA2DS2-VASc ≥ 2) with good INR control, and
• clinicians should consider prescribing dabigatran in patients with:
• poor INR control (less than 60% of time in INR range) despite evidence that they are complying, or
• allergy to or intolerable side effects from coumarin anticoagulants.
Conclusions
• AF is a common condition.
• Patients may be unaware of its presence and are therefore at risk of a stroke
• Effective treatment strategies exist to control symptoms
• Effective treatment strategies exist to reduce the risk of stroke
• Patient education and choice are central to improving the likelihood of treatment success
Tachcardia
Definition of tachycardia
Cardiac arrhythmia with a rate >100 beats per minute (bpm)
Types of tachycardia
Narrow complex tachycardias
Regular (supraventricular tachycardia [SVT])
Sinus tachycardia
Physiological response to insult. Impulse originates
from sino-atrial (SA) node.
Atrial tachycardia
Aberrant atrial focus producing impulse independent
of SA node
Atrioventricular nodal re-entry tachycardia (AVNRT)
Re-entry circuit within or near AV node
AV re-entry tachycardia (AVRT)
Re-entry circuit conducted from atria to ventricles
via abnormal accessory pathway; usually due to
Wolff-Parkinson-White (WPW) syndrome
Atrial flutter with regular AV block (eg 2:1, 3:1)
Re-entry circuit within the atria
Irregular
Atrial fibrillation (AF)
Atria twitch instead of beating in a coordinated
manner
• Broad complex tachycardias
• Regular
• Ventricular tachycardia (VT)
• Generated by a single ventricular focus
• SVT with bundle branch block (BBB)
• This is rare. Any broad complex tachycardia should
be treated as VT unless there the patient has an old
ECG with clear previous bundle branch block of
unchanged morphology.
• Irregular
• Polymorphic VT (Torsades de pointes)
• Sinusoidal morphology usually due to abnormal
ventricular repolarisation (long QT)
• AF with bundle branch block
Aetiology of tachyarrhythmias (pathological as opposed to
physiological)
• Cardiac
• Post-cardiac arrest
• Post-myocardial infarction (MI)
• Long QT syndrome
• Valvular heart disease
• Cardiomyopathy
• Non-cardiac
• Hypoxia
• Hypovolaemia
• Electrolyte abnormalities
• Especially hypo/hyper-kalaemia, -calcaemia or -
magnesaemia
• Hypoglycaemia
• Hypo/hyperthermia
• Hypo/hyperthyroidism
• Sepsis
• Drug-induced
• Cocaine
• Amphetamines
• Tricyclic antidepressants
• Beta blockers
• Digoxin
• Amiodarone
• Clinical features of tachycardias
• Adverse features
• Shock
• Hypotension, diaphoresis, pallor, increased capillary
refill time (CRT)
• Syncope
• Transient loss of consciousness
• Myocardial ischaemia
• Ischaemic chest pain and/or ischaemic
electrocardiogram (ECG) changes
• Cardiac failure
• Orthopnoea, paroxysmal nocturnal dyspnoea (PND),
bibasal crepitations, raised jugular venous pressure
(JVP)
• Non-adverse features
• Palpitations
• Dyspnoea
• Anxiety
Initial investigation of tachycardia
• Bloods
• Full blood count
• Urea & electrolytes
• Magnesium
• Bone profile (particularly noting calcium and phosphate)
• Thyroid function tests
• Other: liver function (useful pre-medication); coagulation
(may need anticoagulation)
• Chest radiograph (CXR)
Further investigation of tachycardia
• Echocardiogram (echo)
Initial management of tachycardia
• Assess patient from an ABCDE perspective
• Maintain a patent airway
• Use manoeuvres, adjuncts, supraglottic or definitive
airways as indicated
• Controlled oxygen
• Maintain saturations (SpO2) 94-98%
• Attach monitoring
• Pulse oximetry
• Non-invasive blood pressure
• Three-lead cardiac monitoring
• Defibrillator pads
• 12 lead ECG
• Obtain intravenous (IV) access and take bloods
• Give IV fluid challenge if appropriate and repeat as necessary
• Identify and treat any reversible causes e.g. electrolyte
abnormalities on initial VBG
• If adverse features are present [shock, syncope, myocardial
ischaemia, heart failure], prepare for emergency synchronised
DC cardioversion under general anaesthesia or conscious
sedation
• Once ready, warn all those nearby to stand clear and remove
any oxygen delivery device whilst the defibrillator is set to
synchronised mode and charged to 120 J
• Once the defibrillator is charged and all are clear, deliver the
shock
• Should this fail, two subsequent shocks at increasing
increments may be tried
• Should this fail, give a loading dose of amiodarone 300 mg IV
over 10-20 minutes and repeat DC cardioversion followed by
amiodarone 900 mg IV over 24 hours
• If adverse features are not present, assess the rhythm:
• Narrow complex tachycardias (QRS duration <0.12 s)
• Regular: likely SVT
• Attempt vagal manoeuvres
• Valsalva (ask patient to blow into syringe); carotid
sinus massage.
• If this fails then:
• Adenosine 6 mg IV
• Rapid bolus ideally into a large-bore cannula in the
antecubital fossa
• Warn patients of transient unpleasant side effects:
flushing, nausea and chest tightness, ‘feeling of
impending doom’
• Avoid in patients with asthma, WPW syndrome, and
denervated hearts
• Caution in taking theophylline, dipyridamole or
carbamazepine
• If 6mg unsuccessful:
• Adenosine 12 mg IV
• If first 12mg unsuccessful:
• Further adenosine 12 mg IV
• If adenosine is contraindicated, consider verapamil 2.5-
5.0 mg IV, or flecainide 2 mg/kg IVI over 20-30 min if
no evidence of structural heart disease
• Irregular: likely AF
• Onset <48 hours
• Aim for rhythm control
• Flecainide 2 mg/kg IVI over 20-30 min if no
evidence of structural heart disease or
amiodarone 300 mg IV over 20-30 min and 900
mg over 24 hours if flecainide contraindicated
• Anticoagulate with enoxaparin 1.5 mg/kg
subcutaneous (SC) prior to this
• Onset >48 hours
• Aim for rate control
• Metoprolol 5 mg IV OR bisoprolol 5 mg orally
(PO) OR verapamil 5 mg IV
• If signs of heart failure try digoxin 0.5 mg
IVI over 30-60 min
• Digoxin can be added to the above if beta-
blockade unsuccessful
• Anticoagulate with enoxaparin 1.5 mg/kg
subcutaneous (SC) prior to this
• Broad complex tachycardias (QRS duration >0.12 s)
• Regular
• If likely monomorphic VT
• Give amiodarone 300 mg IVI over 20-30 min followed
by amiodarone 900 mg IVI over 24 hours
• Any broad complex tachycardia should be treated as VT
unless there the patient has an old ECG with clear
previous bundle branch block of unchanged
morphology.
• If definitely SVT with BBB
• Try adenosine as for regular narrow complex
tachycardias
• Irregular
• If likely AF with BBB
• Treat as for irregular narrow complex tachycardias
• If likely polymorphic VT (Torsades de pointes)
• Magnesium 2 g IV over 10 min
• Stop any medications which prolong the QT interval
• Correct any electrolyte abnormalities if not already
done so, and give
Further management of tachycardia
• Request 12 lead ECG once back in sinus rhythm
• Look specifically for ischaemic changes (ST elevation, ST
depression and T wave inversion), prolonged QT interval
(QTc >440 ms) and signs of WPW syndrome (shortened PR
interval, delta wave and broad QRS complex)
• Identify and correct any underlying cause if not already done
so
• Call cardiologist
• Arrange for an implantable cardioverter defibrillator (ICD)
if appropriate
Advanced Life Support (ALS) tachycardia algorithm
Advanced Life Support (ALS) Tachycardia
Algorithm