Cardiac Arrhythmias: An Update

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Cardiac Arrhythmias An Update

• Dr N.M.Gandhi
• Consultant Cardiologist
• Spire Gatwick Park Hospital, Horley
• East Surrey Hospital, Redhill
• Royal Sussex County Hospital, Brighton

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Objectives

• Identify common arrhythmias encountered by the
  family physician
• Discuss initial Mg options
• AF and Ventricular arrhythmias case studies
• Which patients needs to be referred? ECG examples

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THE CONDUCTION SYSTEM
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Atrial Depolarization
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Ventricular Depolarization
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CARDIAC ARRHYTHMIAS

• Disturbances of either
• Impulse generation
• Impulse propagation

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• ELECTROPHYSIOLOGIC PRINCIPLES
• BRADYARRHYTHMIAS
• SINUS NODE DYSFUNCTION
• AV CONDUCTION DISTURBANCES
• TACHYARRHYTMIAS
• ATRIAL TACHYCARDIAS
• VENTRICULAR TACHYCARDIA

A R R H Y T H M I A S
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Bradyarrhythmias

• Impulse formation
• Decreased automaticity Sinus bradycardia
• Impulse conduction
• Conduction blocks 1º, 2º, 3º AV blocks

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Tachyarrythmias

• Impulse formation
• Enhanced automaticity
• Sinus node sinus tachycardia
• Ectopic focus Ectopic atrial tachycardia
• Triggered activity
• Early afterdepolarization torsades de pointes
• Digitalis-induced SVT
• Impulse conduction
• Reentry Paroxysmal SVT, atrial flutter and
  fibrilation, ventricular tachycardia and
  fibrillation.

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Normal Sinus Rhythm
www.uptodate.com
Implies normal sequence of conduction,
originating in the sinus node and proceeding to
the ventricles via the AV node and His-Purkinje
system. EKG Characteristics Regular
narrow-complex rhythm Rate 60-100 bpm Each
QRS complex is proceeded by a P wave P wave is
upright in lead II downgoing in lead aVR
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PAC

• Benign, common cause of perceived irregular
  rhythm
• Can cause sxs skipping beats, palpitations
• No treatment, reassurance
• With sxs, may advise to stop smoking, decrease
  caffeine and ETOH
• Can use beta-blockers to reduce frequency

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PVC

• Extremely common throughout the population, both
  with and without heart disease
• Usually asymptomatic, except rarely dizziness or
  fatigue in patients that have frequent PVCs and
  significant LV dysfunction

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PVC

• Reassurance
• Optimize cardiac and pulmonary disease management
• Beta-blocker
• Ablation in a small number of cases

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Bradyarrhythmias

• Impulse formation
• Decreased automaticity Sinus bradycardia
• Impulse conduction
• Conduction blocks 1º, 2º, 3º AV blocks

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Sinus Bradycardia

• HRlt 60 bpm every QRS narrow, preceded by p wave
• Can be normal in well-conditioned athletes
• HR can be 30 bpm in adults during sleep, with up
  to 2 sec pauses

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Sinus arrhythmia

• Usually respiratory--Increase in heart rate
  during inspiration
• Exaggerated in children, young adults and
  athletesdecreases with age
• Usually asymptomatic, no treatment or referral
• Can be non-respiratory, often in normal or
  diseased heart, seen in digitalis toxicity
• Referral may be necessary if not clearly
  respiratory, history of heart disease

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Sick Sinus Syndrome

• All result in bradycardia
• Sinus bradycardia with a sinus pause
• Often result of tachy-brady syndrome where a
  burst of atrial tachycardia (such as afib) is
  then followed by a long, symptomatic sinus
  pause/arrest, with no breakthrough junctional
  rhythm.

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1st Degree AV Block

• PR interval gt200ms
• If accompanied by wide QRS, refer to cardiology,
  high risk of progression to 2nd and 3rd deg block
• Otherwise, benign if asymptomatic

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2nd Degree AV Block Mobitz type I (Wenckebach)

• Progressive PR longation, with eventual
  non-conduction of a p wave
• May be in 21 or 31

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2nd degree block Type II (Mobitz 2)

• Normal PR intervals with sudden failure of a p
  wave to conduct
• Usually below AV node and accompanied by BBB or
  fascicular block
• Often causes pre/syncope exercise worsens sxs
• Generally need pacing, possibly urgently if
  symptomatic

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3rd Degree AV Block

• Complete AV disassociation, HR is a ventricular
  rate
• Will often cause dizziness, syncope, angina,
  heart failure
• Can degenerate to Vtach and Vfib
• Will need pacing, urgent referral

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Tachyarrythmias

• Impulse formation
• Enhanced automaticity
• Sinus node sinus tachycardia
• Ectopic focus Ectopic atrial tachycardia
• Triggered activity
• Early afterdepolarization torsades de pointes
• Digitalis-induced SVT
• Impulse conduction
• Reentry Paroxysmal SVT, atrial flutter and
  fibrilation, ventricular tachycardia and
  fibrillation.

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SUPRAVENTRICULAR T.

• Sinus Tachycardia
• Atrial flutter
• Atrial fibrilation
• Paroxysmal Supraventricular
• Multifocal Atrial T.
• Preexcitation Syndrome (Wolff-Parkinson-white Sy.)

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Sinus tachycardia

• HR gt 100 bpm, regular
• Often difficult to distinguish p and t waves

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Paroxysmal Supraventricular T.

• Sudden onset and termination
• Atrial rates of 140 to 250 /min
• Normal QRS complexes
• The mechanism is most often reentry.

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Paroxysmal Supraventricular Tachycardia

• Refers to supraventricular tachycardia other than
  afib, aflutter and MAT
• Usually due to reentryAVNRT or AVRT

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PSVT

• CSM or adenosine commonly terminate the
  arrhythmia, esp, AVRT or AVNRT
• Can also use CCB or beta blockers to terminate,
  if available
• Counsel to avoid triggers, caffeine, Etoh,
  pseudoephedrine, stress

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Multifocal Atrial T.

• Is due to enchanced automaticity within the
  atria, resulting in abnormal discharges from
  several ectopic foci
• Most often occurs in the setting of severe
  pulmonary disease and hypoxemia.
• EKG irregular rhythm with multiple (at leats 3)
  P waves morphologies

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Atrial flutter

• Is caracterized by rapid coarse sawtooth
  appearing atrial activity, at rate of 250 to 350
  x min.
• Many of these fast impulses reach the AV node
  during its refractory period, so that the
  ventricular rate is generally lower.
• Frequently it degenerates into atrial fibrilation
• The most expiditious therapy is electrical
  cardioversion, which is undertaken directly for
  highly symptomatic patients. (to revert chronic
  refractory atrial flutter that has not responded
  to other approaches)

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Preexcitation Syndrome

• Wolff-Parkinson-White Syndrome
• EKG Although different types of bypass tracts
  have been identified, the bundle of Kent, is the
  most common and can usually conduct in both the
  anterograde and retrograde directions.

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Atrial Fibrillation

• Irregular rhythm
• Absence of definite p waves
• Narrow QRS
• Can be accompanied by rapid ventricular response

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Atrial fibrillation--management

• Rhythm vs Rate controlif onset is within last
  24-48 hours, may be able to arrange
  cardioversionuse heparin around procedure
• Need TEE if valvular disease (high risk of
  thrombus)
• If unable to definitely conclude onset in last
  24-48 hours need 4-6 weeks of anticoagulation
  prior to cardioversion, and warfarin for 4-12
  weeks after

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AF Medical Management

• Treatment of underlying cause
• Ventricular rate control
• Anticoagulation
• Antiarrhythmics with a view to restore sinus
  rhythm

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Control of Ventricular Rate in Atrial
Fibrillation

• Betablockers
• Calcium channel blockers
• Verapamil, diltiazem
• Digoxin
• Amiodarone

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Anticoagulation

• Assessment of bleeding risk should be part of
  the clinical assessment of AF patients prior to
  starting anticoagulation
• Antithrombotic benefits and potential bleeding
  risks of long-term coagulation should be
  explained and discussed with the patient
• Aim for a target INR of between 2.0 and 3.0
• NICE 2006

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CHADS 2 scoring
CCF Hypertension Age gt 75 Diabetes Stroke/TIA 1 point 1 point 1point 1 point 2 points

• Any patients with AF with a score of /gt2 would
  benefit from being on Warfarin

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Cardioversion

• Cardioversion results in SR in at least 90 of
  cases
• SR is only maintained in 30-50 at one year
• Class 1a, 1c and III agents increase likelihood
  of maintained SR from 30-50 to 50-70 at one year

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Follow-up

• Follow-up after cardioversion should take place
  at 1 month, and the frequency of subsequent
  reviews should be tailored to the patient
• Reassess the need for anticoagulation at each
  review

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VENTRICULAR ARRHYTHMIAS

• Ventricular tachycardia
• Torsades De Pointes
• Ventricular fibrillation

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Ventricular tachycardia

• Is divided in 2 categories
• If it persist for more than 30 seconds sustained
  VT
• Less than 30 seconds nonsustained VT
• Symptoms vary depending on the duration.
• Major manifestations are hypotension and loss of
  consciousness.

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Non-sustained ventricular tachycardia

• Need to exclude heart disease with Echo and
  stress testing
• May need anti-arrhythmia treatment if sxs
• In presence of heart disease, increased risk of
  sudden death
• Need referral for EPS and/or prolonged Holter
  monitoring
• ICD may be life saving

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Torsades De Pointes

• Varying amplitudes of the QRS.
• It can be produced by afterdepolarizations
  (triggered activity).
• Particularly in prolonged QT interval.
• Occur with some drugs (quinidine), electrolite
  disturbances, and congenital prolongation of the
  QT interval.

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Specialist Referral

• ECG Examples

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Contact...

• E-mail nandkumar.gandhi_at_sash.nhs.uk
• drnmgandhi_at_hotmail.com
• Fax [phone]
• Phone Spire - 01293 785511
• ESH - 01737 768511, ext.6333