EKG Rounds

Elizabeth Haney

17 August 2006

Case

26 yo Caucasian male presents to your ED with hx of a single syncopal episode.

Witnessed, <1minute, no Seizure activity, alert following event.

T 37.3/ HR 80reg/ BP 124/76/ RR 12 O2sat 99%RA/ BG 6.2 Asymptomatic in ED, wants to go home!

What else would you like to know?

Additional History

Assoc. with brief episode of palpitations prior to syncope

No SOB, Chest Pain, N/V, HA PMHx: healthy Meds: nil No street drug use FHx: No known CAD/stroke/seizure/syncope.

Father died in his sleep at 34.

His EKG

Any takers on Dx?

Brugada Syndrome

Twelve-lead surface EKG showing typical pattern of right bundle-branch block and ST-segment elevation of "coved type" in leads V1 to V3 in a patient identified after a syncopal episode

Brugada Syndrome

First described in 1992 by Pedro and Josep Brugada

New syndrome: assoc. w/ SCD in pts w/ structurally normal hearts & no evidence of CAD

Pts had a distinct set of EKG abnormalities:-RBBB pattern, and persistent ST-segment

elevation in the right precordial leads (V1-3).

Epidemiology

Prevalence ranges vary: 0.7-1.0% in Japanese studies, 0.6% in Finnish study, 0.4% in US study.

Male:Female ratio up to 9:1. More common in Asian populations.

Up To Date

Genetics

Autosomal Dominant inheritance 15% to 30% of patients with the Brugada

syndrome, mutations have been found in SCN5A, the cardiac sodium channel α-subunit gene located on chromosome 3

Structural Abnormalities

BS not usually assoc. w/ structural heart dz Evidence supporting subtle microscopic

abnormalities incl. localized myocarditis or microaneurysms. Frustaci et al., Cardiac histological substrate in patients with clinical phenotype of Brugada Sundrome. Circ. 2005 Dec 13;112(24):3680-7.

18 pts in study, 14 w/ RV myocarditis, 7 w/ RV microaneurysms

3 Patterns of ST Elevation

Type 1: elevated ST segment ( >2 mm) descends with an upward convexity to an inverted T wave. = "coved type" Brugada pattern.

Type 2 and type 3 patterns have a "saddle back" ST-T wave configuration, with the elevated ST segment descends toward the baseline, then rises again to an upright or biphasic T wave. The ST segment is elevated

1 mm in type 2 and <1 mm in type 3.

Brugada Waves: 3 Types

Z Kardiol 2004; 93:784–790Thanks Dr. Haager

‘Coved’ ST segments w/ T wave inversion

‘Saddleback’ ST segments•Type 2

•Positive or biphasic T wave•1mmSTE

•Type 3•Positive T wave•<1mm STE

Differential Dx

EKG findings alone not diagnostic. DDx:

RV pathology Compression (tumor, hemopericardium) Inferior MI, RV ischemia, Cardiac contusion RBBB, LVH

Arrhythmogenic right ventricular cardiomyopathy Drugs: class IA (procainamide…), IC (propafenone,

flecainide…), cocaine, TCA’s, and more Hyperkalemia, hypercalcemia

Brugada Pattern vs Syndrome

Brugada Pattern = EKG findings without other clinical criteria

Brugada Syndrome = typical EKG findings with other clinical criteria

Clinical Spectrum

Clinical Manifestations

Related to life-threatening ventricular arrhythmias.

SCD occurs in as many as 1/3rd of pts! Arrhythmic events generally occur between

ages of 22-65. More common at night and during sleep,

usually not related to exercise.

Diagnostic Criteria Type I In evolution. “Strongly consider in pts that meet the following criteria”

Type I EKG pattern of type 1 ST segment elevation (coved type) in >1 lead of V1-

V3and 1 of:

Documented VF Self-terminating polymorphic VT Family Hx of SCD <45 Other Family members w/ Brugada ECG pattern EPS inducibility of VT Unexplained syncope suggestive of a tachyarrhythmia Nocturnal agonal respirations

Wilde et al. Eur Heart J 2002;23:1648

Diagnostic Criteria Type 2 + 3 Type 2 or 3

EKG pattern of type 2 or 3 ST segment elevation (saddle-back type) in >1 lead of V1-V3, with conversion to type 1 following challenge w/ a sodium channel blocker

And1 of: Documented VF Self-terminating polymorphic VT Family Hx of SCD <45 Other Family members w/ Brugada ECG pattern EPS inducibility of VT Unexplained syncope suggestive of a tachyarrhythmia Nocturnal agonal respirations

Proposed Work-Up

Treatment

Refer for EP studies ICD placement When provided with an ICD, mortality at 10-

year follow-up has been 0%. Quinidine (sodium channel blocker) research

shows promise. Currently may have role for pts with ICD and frequent discharges (consider amiodarone, quinidine or hydroquinidine). Uptodate.com

Take Home

Be familiar with the EKG manifestations of Brugada syndrome to ensure early diagnosis and prompt referral.

References Zipes: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed. Brugada P, Brugada J: Right bundle branch block, persistent ST segment elevation

and sudden cardiac death: a distinct clinical and electrocardiographic syndrome. J Am Coll Cardiol 1992;20:1391-1396

Littmann et al., Brugada syndrome and “Brugada sign”: Clinical spectrum with a guide for the clinician ,American Heart Journal, 145;768-778

Frustaci et al., Cardiac histological substrate in patients with clinical phenotype of Brugada Sundrome. Circ. 2005 Dec 13;112(24):3680-7.

Wilde et al., Proposed diagnostic criteria for the Brugada syndrome. Eur Heart J 2002; 23:1648

Mattu et al., The Brugada Syndrome, Am J Emerg Med 2003;21:146-151 Uptodate.com J.,R., and P. Brugada, Determinants of Sudden Cardiac Death in Individuals With the

Electrocardiographic Pattern of Brugada Syndrome and No Previous Cardiac Arrest. Circ. Dec. 2003; 108: 3092-3096

Pts w/ ECG diagnostic of Brugada syndrome and no previous cardiac arrest have an 8% risk of SCD during a short-term follow-up period of 2 years.

Lowest-risk group = no syncopal episodes, diagnostic ECG only with drug challenge, and noninducibility during programmed ventricular stimulation (0.5% incidence of events).

Highest-risk group = combo of a previous history of syncope, a spontaneously abnormal ECG, and inducible sustained arrhythmias during programmed ventricular stimulation (27.2% incidence of events).

J.,R., and P. Brugada, Determinants of Sudden Cardiac Death in Individuals With the Electrocardiographic Pattern of Brugada Syndrome and No Previous Cardiac Arrest. Circ. Dec. 2003; 108: 3092-3096