Arrhythmias: typical manifestations and their management within the acute setting and in primary care

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Arrhythmias typical manifestations and their
management within the acute setting and in
primary care

• Dianne Snowden
• St Marys Hospital, London

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Agenda

• Common Arrhythmias
• Manifestations in primary care
• Treatment in secondary / tertiary care

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National Service Framework
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National Service Framework for Arrhythmias

• Assessment by Arrhythmia Specialist
• Sudden Cardiac Death
• Screening for at risk patients
• Rapid assessment of syncope
• Implantable Defibrillators by NICE guidelines
• Patient Support and Family screening
• Atrial Fibrillation
• Stroke Prevention
• Therapy for symptoms
• Biventricular devices for Heart Failure

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What is this?
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Atrial Fibrillation

• Occurs in 1 of population but prevalence
  increases with age
• Prevalence may be increasing
• 22 increase in men
• 14 increase in women (1994-1998)
• Estimated up to 0.5 of total NHS budget spent on
  AF
• NICE Guidance July 2006

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Mechanisms of AF
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Demographics
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Causes

• Any STRUCTURAL heart disease- especially those
  associated with
• LA enlargement
• LVH
• Reduced systolic function
• Valvular (especially mitral) heart disease
• Hypertensive Heart disease
• Cardiomyopathy of any cause (up to 30)
• Hypertrophic cardiomyopathy

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Causes contd

• Hyperthyroidism
• May be only clinical manifestation
• Intercurrent Illness
• Especially LRTI, UTI in elderly
• Perioperative AF
• e.g hip replacement
• Alcohol- probably genetic predisposition

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Diagnosis
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Diagnosis

• Irregularly irregular pulse
• Possible symptoms
• Shortness of breath
• Tiredness
• CVA
• Palpitations
• NONE

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Treatment of Atrial Fibrillation

• AF in AE
• Rate and / or Rhythm Control?
• Reducing Embolic Risk

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Safest Drug in the Management of Atrial
Fibrillation

• Electricity!

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Medical therapy

• Digoxin
• Not good at controlling heart rate
  physiologically
• Does not cardiovert
• Amiodarone
• Does not work rapidly to cardiovert chemically
• Has little effect on ventricular rate
• If patient is very unwell with AF- cardiovert
  electrically

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Medical therapy

• Sotalol
• Need high doses for effective treatment (240-320
  mg/day)
• Otherwise less effective and less well tolerated
  than standard beta blocker
• Flecanide
• Best drug to chemically cardiovert
• But electrical cardioversion is more effective
  and safer

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Treatment of Atrial Fibrillation

• AF in AE
• Rate and / or Rhythm Control?
• Reducing Embolic Risk

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• In atrial fibrillation should we just accept
  permanence and control rate or strenuously
  attempt to restore and maintain sinus rhythm?
• AFFIRM, RACE (PIAF, and STAF) Trials

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NICE approach to Rate vs Rhythm Control

• Consider both in all patients
• Rhythm control the preferred strategy in
• Young patients (lt65yrs)
• Highly symptomatic patients
• Patients who develop heart failure with AF
• Newly diagnosed AF or AF with clear precipitant

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Rhythm control

• Standard beta-blocker is first line treatment
  (they do help maintain sinus rhythm)
• If ineffective consider
• Flecanide, sotalol, amiodarone
• Non-pharmalogical strategies (ablation/pacing)

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Rate control for atrial fibrillation

• Standard beta blocker
• Rate limiting calcium channel blocker e.g.
  Verapamil, Diltiazem
• (Digoxin- only in sedentary patients intolerant
  of the above)
• No role for amiodarone (does not control rate
  well) or sotalol (not trying to restore sinus
  rhythm)

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A word on Digoxin

• Does not control rhythm
• Poor at controlling physiological heart rate
• Potentially toxic
• It is not harmful but not beneficial in heart
  failure with AF
• Has extremely limited role in 2007

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A word on Amiodarone

• Does not control ventricular rate
  physiologically- no role in permanent AF
• Is toxic and interacts unreliably with warfarin
• Only has a role in difficult PAF or
  cardioverted persistent AF to maintain sinus
  rhythm- but in those cases non-pharmacological
  management is probably preferred

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Treatment of atrial fibrillation

• AF in AE
• Rate and / or Rhythm Control?
• Reducing Embolic Risk

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Effects of anticoagulation rates on stroke rates
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• All studies show superiority of standard dose
  warfarin (INR 2-3) over any other strategy in all
  groups
• The beneficial effect is even more marked in the
  elderly (gt75) where the risk of embolic stroke
  climbs significantly
• But clinicians remain circumspect about using
  warfarin in the real world (especially in the
  elderly)

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NICE risk stratification

• Low risk-
• Age lt65 with no other risk features
• Medium risk-
• Agegt65 with no other risk features.
• Age lt75 with hypertension, diabetes or vascular
  disease
• High risk-
• Prior stroke or embolic event
• Age gt75 with hypertension, diabetes or vascular
  disease
• Valvular heart disease or impaired LV function

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Alternative stratification - CHADS
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Tertiary Centre treatment of AF

• Dependent on symptoms
• ANTIO-COAGULATION
• DC Cardioversion
• Ablation 70 success at first ablation
• Ablate and Pace

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Atrial Fibrillation Ablation
Pulmonary Vein Isolation
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ENOUGH AF!!!!!!
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Atrial Flutter
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Diagnosis in primary care

• ECG regular flutter waves
• Ventricular rate will be a 300bpm, 150bpm, 75bpm
  and regular due to pathway
• Possible will predispose to AF

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Treatment of atrial flutter

• Difficult to control
• Rate control important
• Flecainide may control but need BB as well
• Flutter ablation ablate pathway 98 success

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SUPRAVENTRICULAR TACHYCARDIAS
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Supraventricular Tachycardia - diagnosis

• Fast and regular
• Sudden onset and offset
• May be associated with
• Palpitations
• Syncope / presyncope
• Shortness of breath
• Chest pain

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AV Nodal Re-entry Tachycardia

• Re-entry circuit within AV node
• Rate usually 130-250/min
• CSM or adenosine may terminate arrhythmia
• Alternatives include cardioversion (electrical or
  drug) and overdrive pacing
• Prophylaxis with class II, IV, III, Ia, Ic drugs

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AVNRT
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Treatment of AVNRT

• Anti-arrhythmics
• Ablation of pathway
• 98 success rate

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AV Re-entry tachycardia

• Accessory pathway allowing transition of
  electical impulse from SA node to ventricle
  without passing through AV node.
• Wolff Parkinson White syndrome
• 0.15 of population
• Resting ECG shows short PR and delta wave
  pre-excitation
• May cause AV re-entry tachycardia
• A fib may be dangerous due to rapid conduction

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Mechanism of preexcitation
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Pre-excitation
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Treatment of WPW / AVRT

• Adenosine may reveal pathway by blocking AV node
• Ablation of accessory pathway 98 success rate

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Ventricular tachycardias

• Sudden onset
• Rapid regular rhythm with broad complex QRS
• Risk of degeneration into ventricular
  fibrillation
• Need prompt treatment

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100,000 PATIENTS PER YEAR DIE OF SCD IN THE UK









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Treatment

• AMBULANCE!
• Cardioversion (electrical or drug) can restore SR
• Overdrive pacing is an alternative
• Device therapy

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Anti-tachycardia pacing
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NICE guidelines primary prevention
Primary Prevention for patients with

• A history of previous myocardial infarction (MI)
  and all of the following
• Non sustained VT on Holter (24 hr ECG) monitoring
• Inducible VT on electrophysiology testing
• Left ventricular dysfunction with an ejection
  fraction (EF) less than 35 and no worse than
  class III of the NYHA
• functional classification of heart failure
• A familial cardiac condition with a high risk of
  sudden death, including long QT syndrome,
  hypertrophic cardiomyopathy, Brugada syndrome,
  arrhythmogenic right ventricular dysplasia (ARVD)
  and following repair of Tetralogy of Fallot

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NICE guidelines secondary prevention
Cardiac arrest due to either ventricular
tachycardia (VT) or ventricular fibrillation
(VF)
Spontaneous sustained VT causing syncope or
significant haemodynamic compromise
Sustained VT without syncope / cardiac arrest,
and who have an associated ejection fraction
(less than 35) but are no worse than class 3 of
the New Heart Association (NYHA) functional
classification of heart failure.
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Long QT Syndrome
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Brugada Syndrome
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Function of the ICD

• To reliably differentiate between
• sinus rhythm
• sinus tachycardia
• ventricular tachycardia
• ventricular fibrillation
• To give or withhold therapy as appropriate

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Key device system components
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• Dianne Snowden
• 020 7886 2378
• 07768 980832