Risk Stratification in Patients with Brugada Syndrome

 

Features of the Brugada syndrome:

(1) family history with inheritance of mutations in the SCN5A gene

(2) ECG pattern of ST-segment elevation >= 2 mm in leads V1, V2 and V3, which may be spontaneous or induced by intravenous administration of sodium channel blockers

(3) variable right bundle branch block

(4) variable history of syncope

 

A family history of unexplained sudden death was found in 20% of probands in the study population. This had a sensitivity of 22% and specificity of 65% for cardiac arrest in the proband.

 

Induction of ST wave changes with intravenous sodium channel blocker: either

(1) 2 mg/kg flecainide

(2) 1 mg/kg ajmaline

Spontaneous ST Segment Elevation	History of Syncope	Risk Group	Hazard Ratio
yes	yes	high	6.4
yes	no	intermediate	2.1
no	yes	low	1.0
no	no	low	1.0

 

Risk Group	Percent of Study Group	Percent with Cardiac Arrest
high	10%	44%
intermediate	41%	14%
low	49%	5%

 

General management:

(1) Sodium channel-blocking agents and tricyclic antidepressants should be avoided. (NOTE: This prohibition may extend to any drug that prolongs the corrected QT interval, but this needs to be checked on.)

(2) Patients in the high risk group should receive an implantable cardioverter-defibrillator.

(3) Patients in the low risk group should be advised to report immediately if syncope or palpitations occur. They can be followed clinically and should be re-evaluated as they get older.

(4) Management for a patient in the intermediate group is variable. They should be advised to report immediately if syncope or palpitations occur. Implantation of a cardioverter-defibrillator should be considered; a small percentage of the patients will have sudden death starting after age 20 with increasing frequency as the patient ages. Since women appear to have a lower risk of cardiac arrest (see Table 2, page 1344), there could be an argument to follow them as early adults.