Films and Scans
Your patient is a 51-year-old male immigrant from Northeast Thailand who complains of recurring syncopal episodes. The nurse says the computer is reading this as an acute MI. What is your interpretation? (choose only one)
Click the tracing for a high-resolution image.
A. Atypical RBBB. Magnify Lead I and note the small terminal S-wave. This tracing meets the Triad: 1.QRS duration > or = 0.12 sec 2. Lead I is biphasic with terminal S-wave 3. Leads V1, V2 and V3 with RSR’ (slur or notch).
B. Lown-Ganong-Levine Syndrome (LGL). The peculiar shape of the ST segment in Leads V1, V2 and V3 are probably related to the retrograde propagation through the accessory pathway.
C. Wolff-Parkinson-White syndrome (WPW). The peculiar shape of the ST segment in Leads V1, V2 and V3 are probably related to the retrograde propagation through the accessory pathway (Bundle of Kent).
D. The Brugada Syndrome. Characterized by the peculiar shape and elevation of the ST-segments of Leads V1, V2 and V3 (note angle of nearly 45 degrees) and T-wave inversion.
E. Atypical Left Anterior Fascicular Block (LAFB). The electrical axis is -75 degrees. This tracing meets the triad of 1. Axis < -45 degrees 2. Small Q’s Leads I and avL 3. Small R’s Leads II, III and avF
Discussion: This is a classic example of the Brugada Syndrome. You can easily see why one might interpret the tracing as one of an acute ST-elevation MI or STEMI (Anteroseptal). Note particularly the ST elevation and T-wave inversion in Lead V3.
Brugada Syndrome: This cardiac abnormality is a genetic disorder (autosomal dominant transmission). It is characterized by an electrical abnormality with a structurally normal heart. The syndrome proper is characterized as follows (without symptoms it is referred to as the Brugada Sign):
1. Clinical episodes of near syncope, syncopal episodes, seizures or sudden death.
2. Structurally normal heart.
3. Characteristic ECG pattern displaying ST elevation and T-wave inversion in Leads V1, V2 and V3 (pattern resembles RBBB).
12-Lead ECG Characteristics: For emphasis, I have magnified Lead V2. The ST segment assumes a peculiar ramp-like elevation at an angle of nearly 45 degrees. The T-wave is inverted (negative or biphasic). These ST-T changes are the hallmark of the Brugada Syndrome. QT interval is usually normal
Common misdiagnosis of the Brugada tracing:
A careful analysis of the tracing above will reveal why it is frequently misdiagnosed as
a. Atypical RBBB — This tracing demonstrates RSR’ in Lead V2 with a biphasic Lead I and small terminal S-wave. The QRS duration is slightly prolonged.
b. Acute Anteroseptal MI – ST elevation (concave down) in Leads V1, V2 and V3.
Incidence: This syndrome has been recognized virtually worldwide, less common in the United States and most common in Southeast Asia (Thailand and Laos). Incidence of male:female is approximately 8:1. Death commonly occurs during rest or sleep (in Thailand, it is known as “lai tai” [“death during sleep”]). It is stated to be responsible for five deaths per year per 10,000 population in these areas where it is endemic. The arrhythmia leading to sudden death is Polymorphic Ventricular Tachycardia (Torsades de Pointes) with degeneration to ventricular fibrillation.
Treatment: The objective of treatment is the prevention of ventricular tachycardia and sudden death. Patients with electrocardiographic changes of Brugada Sign but negative for syncope, pre-syncope or seizures should all be referred to the cardiologist for a work-up and treatment recommendation (choose a cardiologist who has a familiarity with this disorder). If the patient is experiencing symptoms related to transient Ventricular Tachycardia, antiarrhythmic drugs including beta blockers and amiodarone are ineffective to prevent Ventricular Tachycardia and sudden death. The only effective treament mode is automatic implantable defibrillation.