Arrhythmias
Arrhythmias - Objectives
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Definition
Clinical presentation
Diagnosis - ECG analysis
Classification
Management
Sinus rhythm - SA node controls the
ventricle on a 1 :1 ratio
Definition of arrhythmia
Ventricular activity (QRS) is not regulated by
SA node on a one to one conduction
Interruption in conduction – Heart block
Abnormal focus - Atrial tachycardia, VT
Re entry circuit - SVT, Atrial flutter, VT
Classification of Arrhythmias
• Narrow complex tachycardia (NCT)
• Broad complex tachycardia (BCT)
• Bradycardias and A-V Block
Clinical presentations
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Cardiac arrest - VT,VF, Ventricular asystole
Breathlessness
Chest pain
Dizziness
Embolic episode
Falls
Low GCS
Hypotension
Syncope
Suspected Arrhythmia
• Immediate assessment
–A
–B
–C
• Establish intravenous access
• Attach cardiac monitor
• Classify arrhythmia
Diagnosis and classification of
arrhythmia
1. ? Sinus rhythm (SR)
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P preceding QRS and PR interval equal
Assess in lead II or V1
If not in SR
2. Heart rate
> 100- Tachyarrhythmia
< 60 – Bradyarrhythmia
3. QRS duration
< 120 ms - Narrow Complex Tachycardia
> 120 ms - Broad Complex Tachycardia
4. Assess whether Regular or Irregular NCT
Arrythmia
Tachyarrhythmia
Narrow QRS
Regular
Irregular
Bradyarrythmia
Broad QRS
Regular
Irregular
Regular narrow-complex tachycardia
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Atrial flutter with regular AV block
Re entrant tachycardia
• AV nodal (AVNRT)
• Atrio ventricular(AVRT)
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Atrial tachycardia
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Abnormal P wave
Atrial flutter
Diagnosed only in the presence of
flutter waves on the ECG
Management of Atrial flutter (<48 hrs)
• DC Cardioversion
– Haemodynamic compromise….
– Normal echo
– No underlying cause
• Drugs (less effective)
– Flecainide better avoided
– Amiodarone - drug of choice to revert to SR (50 %)
– Ibutilide may reduce the need for DC shock .
Re - entrant Tachycardia
No P wave present – hidden in ST or T
waves
Management of Re - entrant tachycardia
(AVNRT / AVRT)
Vagal manoeuvre
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Carotid sinus massage
Valsalva manoeuvre
Adenosine test
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NOT in acute asthmatics (bronchospasm)
Warn patient of symptoms (chest pain, SOB,flushing)
Flecainide
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2mg/Kg ( 30-60) min if adenosine fails.
DC cardioversion
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If haemodynamic instability and no response to adenosine or flecainide
DC seldom required in Re-entrant tachycardia
Management of Re - entrant tachycardia
(AVNRT/ AVRT)
To prevent recurrence:
• Flecainide or B-blocker
• Consider Ablation for all Re-entrant tachycardias
Irregular narrow-complex tachycardia
• Atrial fibrillation
• Atrial flutter
• Multifocal atrial tachycardia
Atrial Fibrillation
Atrial fibrillation
Classification of Atrial fibrillation
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Acute Atrial fibrillation (within 7 days)
Chronic Atrial fibrillation
– Paroxysmal:
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Spontaneous termination < 7 days
Persistent:
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Continues indefinitely unless cardioverted
Permanent:
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Cannot restore sinus rhythm
Cardiac causes of AF
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Hypertension
Valvular heart disease
Coronary Heart disease
Cardiomyopathy
Post cardiac surgery
Pericardial disease
Non cardiac causes of Atrial Fibrillation
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Alcohol
Lung disease – Pneumonia, COPD
Thyroid disease
Sepsis
Stroke
Post surgery
Echocardiography in AF
• Identify the cause - Mitral valve, myocardial
or pericardial
• Assess LV size and Function - H/T, IHD,
cardiomyopathy
• Assess atrial size /clot
Management of acute Atrial
fibrillation
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If < 48 hrs of onset
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DC cardioversion if haemodynamic compromise
IV Flecainide 2mg/kg over 30-60 min if
echocardiography normal.
If > 48 hrs
Rate control
Early Cardioversion after TOE
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– Delayed Cardioversion after 4 weeks of warfarin
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Drugs to achieve rate control
• Verapamil / Diltiazem
– Avoid if IHD, LV impairment
• Beta blocker
– Usual CI should be observed
• Digoxin
– often ineffective rate control on exertion hence
combined with beta or Ca channel blocker
• Amiodarone
Rate or Rhythm control in AF?
Acute AF
Rhythm control
Rate control
Persistent AF
Rhythm control
Rate control
Permanent AF
? Ablation
Paroxysmal AF
Rhythm/Ablation
Rate-control in AF
Try rate control first for patients with Persistent
AF:
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> 65 years
Duration > 1 year
Hypertension with LVH
Dilated LA > 5 cm
Unsuitable for cardioversion
Rhythm control in AF
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Acute AF
AF < 6 months
< 65 years
Structurally normal heart
? Non ischaemic LV dysfunction
Maintaining Sinus Rhythm in AF
Normal Heart /No CHD
Flecanide/Propafenone
Disopyramide
Mild LVH/CHD
Sotalol
Significant LVH/HF
Beta blocker/
Amiodarone
Digoxin not useful for maintaining SR
Broad Complex Tachycardia
• Clinically
Any cardiac rhythm >100 /min, with QRS duration
of >0.12s
• Electrophysiologically
Mostly ventricular in origin, involving automatic
focus or re-entry circuit within the ventricles
Broad Complex Tachycardia
Causes:
• Ventricular Tachycardia (VT)
• Supraventricular arrythmia with aberrant
conduction (BBB, rate related BBB)
• WPW with antidromic pathway
Default diagnosis is VT.
Ventricular Tachycardia
Ventricular Tachycardia
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Monomorphic Ventricular Tachycardia
(>120/min)
Accelerated idioventricular rhythm (<
120/min)
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Polymorphic Ventricular Tachycardia
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AMI most common cause - Rx not necessary
Acute MI or ischaemia
Long QT interval (Torsades)
VT
• NSVT- >3 VEs (rate>120) lasting <30s
– Prognostically significant in HCM, DCM, post MI
with low EF
– Rarely in structurally N heart- not associated with
risk
• VT in structurally normal heart
– RVOTT and Fascicular tachycardia
– Good prognosis, good response to RFA if
symptomatic
VT
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P/H IHD,drugs
VA dissociation
QRS>140ms
QRS>160ms
Left axis with RBBB
Concordance in chest
leads
• Fusion or Capture
beat
“SVT”
• No cardiac history
Ventricular tachycardia
AF with LBBB
Assessment of patient with BCT
• Immediate assessment
–A
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• Establish intravenous access
• Attach cardiac monitor (ideally with printout)
Management of VT
If patient compromised (low BP, decreased
conscious level, heart failure, chest pain):
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Urgent electrical cardio-version
If patient not compromised:
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LV not impaired - IV lignocaine
If evidence of cardiac failure or poor LV function
- IV amiodarone
Management of VT
Second-Line drugs:
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Beta-blockers (avoid in heart failure)
Flecanide (avoid if LV impaired or IHD)
Mexiletine (do not use in cardiogenic shock)
Procainamide (can cause torsade)
Causes of VT
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IHD
Cardiomyopathy
Arrythmogenic RV dysplasia
Brugada syndrome
Congenital Heart disease
Causes of Torsades de pointes (TDP)
• Congenital long QT syndromes
– Jervell and Lange-Nielsen syndrome
– Romano-Ward syndrome
• Acquired long QT syndromes
– Bradycardia
– Electrolytes – Hypokalaemia, Hypomagnesaemia
– Drugs
Drugs causing long QT Syndromes
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Antiarrythmics – Sotalol, Amiodarone,
disopyramide
H1-receptor antagonists - Terfenadine, astemizole
Cholinergic antagonists – Cisapride
Antibiotics - Erythromycin, clarithromycin
Antifungals - Ketoconazole, itraconazole
Psychotropic agents - Haloperidol, phenothiazines
Tricyclic and tetracyclic antidepressants
Long QT Syndrome
ECG in Torsades de pointes
• Paroxysms of 5-20 beats, with a heart rate of
200/min
• Sustained episodes occasionally can be seen
and can degenerate in VF
• Complete 180° twist of QRS complexes within
10-12 beats
• Torsade occurring in the setting of acquired
long QT is preceded by pauses in almost all
cases
Torsades de points
Management of Torsades de points
• Give all patients IV magnesium even when Mg
normal:
– 8mmol stat followed by 2.5mmol/hr infusion
• Isoprenaline infusion can help suppress TDP
• Overdrive atrial pacing (if no AV block) at rate of
100 bpm is treatment of choice
• DC cardioversion if sustained
• Stop antiarrhythmic drugs
Ventricular Fibrillation
Ventricular Fibrillation
• Uncoordinated contraction (fibrillation) of the
ventricles
• Most common arrhythmia in cardiac arrest
• Manifests as completely irregular activity on
ECG
Bradyarrythmias
• SA node disease
• AV block
• First degree
• Second degree – Mobitz 1 or Mobitz 11
• Third degree or Complete block
• Intraventricular block – Bifasicular,
Trifasicular
Heart Block
First degree AV block
First degree AV block
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Prolonged PR interval > 200ms
Every P wave followed by a QRS complex
Can be normal
Rarely causes symptoms
Mobitz type1/ Wenckebach AV block
Mobitz type 1 AV block
• Progressive prolongation of PR interval until a
QRS complex is “dropped”
• Usually benign and requires no treatment
Mobitz type 2
Mobitz type 2 block
• Intermittently non-conducted P waves
• No prolongation of P-R interval
• Block occurs in the His-Purkinje system, and
therefore the QRS complex is often wide
• May progress to complete heart block
• Requires pacemaker
Complete heart block
Complete heart block
• Complete dissociation of atrial and ventricular
activity
• Ventricular escape rhythm of 40 bpm
• Many causes
• Requires pacemaker insertion
Indications for temporary pacing
• Cardiac arrest with ventricular asystole or
bradycardia
• Asystole due to eletrolyte imbalance
• Mobitz II or CHB in anterior infarct
• CHB in Inferior MI if HR < 40, Ventricular arrythmia
Intracardiac defibrillator (ICD)
Indications for ICD
• Impaired LV with sustained or non sustained VT
• Resuscitated VF/VT arrests not due to reversible
cause
• Patients with Previous MI , LVEF<35%,QRS >120
• Brugada syndrome, ARVD, Long QT syndrome
What the Guidelines say…. ICD indications
Yes
No
No Comment
Secondary Prevention
Absolute redn in
mortality with ICD
(per annum)
3.5%
(VF,unstable VT, VT with poor LV)
Primary Prevention
- Post MI, EF<0.36,
8%
NSVT,+ve EPS
-Post MI, QRS>120ms,
EF<0.30-0.35
5%
- High risk inherited
conditions (HOCM, Brugada,
LQTS)
2-3%
- Post MI, EF<0.30-0.35
2.7%
- DCM, EF<0.30-0.35
1.3 - 3%
NICE
ACC/AHA/ESC
ICD –Delivering Shock
Any questions?