·
ECG
changes found in .4% of asymptomatic people in the USA. Much higher in Southeast Asian populations.
·
4
to 5% of sudden cardiac deaths, predominantly those occurring at night and in
young people. Males predominate.
·
50%
have an identified genetic component – probably a sodium channel gene.
·
20%
of cardiac arrests where the heart is structurally normal.
·
Most
people are asymptomatic
·
Commonest
presentation is syncope or sudden death.
Chest pain is not common.
·
Atrial
fibrillation is more likely to occur.
Think about this diagnosis.
·
Pre-terminal
rhythms most commonly polymorphic or monomorphic ventricular tachycardia
leading to ventricular fibrillation.
·
Common
contributor to cocaine-induced arrhythmias.
·
Possibly
triggered by any drug blocking sodium channels including tricyclic overdose,
psychotropics, flecanide and procainamide.
ECG Findings: (see Figure)
·
Polymorphic
or monomorphic ventricular tachycardia when symptomatic.
·
Asymptomatic
patients – usually changes in V1, V2, and sometimes V3. Pseudo RBBB pattern (not seen in limb leads)
with convex or concave ST elevation and no reciprocal findings.
ECG findings plus at least 1 of the following:
·
Documented
ventricular fibrillation
·
Self-terminating
polymorphic ventricular tachycardia (VT)
·
Family
history of sudden cardiac death at <45 years
·
Type
1 ST segment elevation in family members
·
Electrophysiologic
inducibility of VT
·
Unexplained
syncope suggestive of a tachyarrhythmia
·
Nocturnal
agonal respiration
·
Symptomatic
– cardioversion or defibrillation based on ECG. If polymorphic ventricular tachycardia remember to use unsynchronized
shocks at 200-360 joules (monophasic).
·
Asymptomatic
– refer quickly for electrophysiologic testing. Avoid drugs which block sodium channels. Most patients require and implantable
cardioverter-defibrillator.
·
Audio
– Digest Emergency Medicine 2007. Vol
24(1)
·
UpToDate
Ver. 14.2 2006. Brugada syndrome and sudden cardiac death.
