Wolff-Parkinson-White Syndrome

OVERVIEW

  • pre-excitation syndrome
  • additional or accessory AV pathway
  • during sinus rhythm the atrial impulse will reach the ventricles via both AV node and accessory AV pathway
  • accessory pathway conducts impulse faster -> pre-excitation and short PR interval
  • on reaching the ventricles the pre-excitation impulse is not conducted via the conducting system -> ventricular activation is slow (delta wave and T wave abnormalities)

CLINICAL FEATURES

  • palpitations
  • chest pain
  • SOB
  • cardiogenic shock
  • collapse
  • VF arrest
  • AF or SVT

INVESTIGATIONS

Resting ECG

  • short PR (0.12s)
  • T wave abnormalities
  • dominant R in V1 and V2
  • may have inferior q waves but not diagnostic of MI

Type A – tall R in V1, LAD (left posterior septal path) Type B – deep S in V1, LAD (right lateral or postero-septal path) Type C – tall R in V1, inferior axis – 90º (left lateral path)

Symptomatic ECG

  • AV re-entrant tachycardia or AF
  • AVRT: the re-entry impulse usually travels down the AV node and back up the accessory pathway (delta wave not present), occasionally the re-entry impulse may pass down the accessory pathway and up the AV node (wide QRS tachycardia + delta wave)
  • AF: rapid, irregular QRS complexes with variable QRS duration -> very rapid ventricular response -> cardiogenic shock -> VF

MANAGEMENT

Acute

  • unstable -> synchronised DC shock
  • stable -> anti-arrhythmics (prolongation of accessory pathway: sotalol, amiodarone, flecanide, procanamide)
  • drugs that shorten refractory period are contraindicated (digoxin)
  • drugs that increase ventricular rate avoid (verapamil and lignocaine)
  • drugs that have no effect on refractory period of accessory pathway are useless (beta-blockers)

Long-term

  • radio-frequency ablation

References and Links

LITFL


CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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