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Should all individuals with a nondiagnostic Brugada-electrocardiogram undergo sodium-channel blocker test?
Alessandro Zorzi1, Federico Migliore, Elena Marras
1Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Padova, Italy.
Insights
The sodium-channel blocker test helps identify high-risk individuals with Brugada-electrocardiogram (Br-ECG). A positive test in symptomatic patients indicates a higher event rate, aiding risk stratification.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Brugada-electrocardiogram (Br-ECG) is characterized by specific ST-segment elevation patterns.
- Sodium-channel blocker tests are used to unmask diagnostic Br-ECG in patients with nondiagnostic types (2 and 3).
Purpose of the Study:
- To evaluate the prognostic significance of the sodium-channel blocker test in individuals presenting with a nondiagnostic Br-ECG.
Main Methods:
- 153 patients with type 2/3 Br-ECG underwent a sodium-channel blocker test (flecainide or ajmaline).
- Nondiagnostic Br-ECGs were identified during evaluations for cardiac arrest, syncope, family screening, or incidentally.
- Spontaneous type 1 Br-ECG was excluded through serial ECGs and specific lead recordings.
Main Results:
- The sodium-channel blocker test was positive in 50% of patients.
- During follow-up (59 months), 5.9% experienced events (syncope, defibrillator interventions, sudden death).
- A positive test correlated with higher event rates in symptomatic patients (P=.01) but not asymptomatic ones (P=.18).
Conclusions:
- Asymptomatic individuals with nondiagnostic Br-ECG have a low event incidence, irrespective of test results.
- In symptomatic patients, a positive sodium-channel blocker test indicates an adverse arrhythmic outcome, aiding risk stratification.
Background:
The diagnostic Brugada-electrocardiogram (Br-ECG) is characterized by "coved-type" ST-segment elevation (type 1) in V(1) to V(2)/V(3). The sodium-channel blocker test is clinically used to unmask diagnostic Br-ECG in patients with nondiagnostic "saddle-back" Br-ECG (type 2 and type 3).
Objective:
To assess the prognostic value of the sodium-channel blockers test in individuals with a nondiagnostic Br-ECG.
Methods:
We studied 153 consecutive patients (128 men; age 41.7 ± 14.0 years) with a type 2/3 Br-ECG who underwent a sodium-channel blocker test with either flecainide (48%) or ajmaline (52%). Nondiagnostic Br-ECGs were identified during the evaluation of cardiac arrest in 5 patients (3%), syncope in 36 (24%), cascade family screening in 48 (31%), and incidental ECG in 64 (42%). A spontaneous type 1 Br-ECG was systematically excluded by serial ECGs (6.1 ± 0.4) and recording of right precordial leads both at standard and second and third intercostal spaces.
Results:
The sodium-channel blocker test result was positive in 76 (50%) patients. During a follow-up of 59 ± 33 months, 9 (5.9%) patients experienced events such as syncope (n = 4), appropriate interventions of defibrillator (n = 4), or sudden death (n = 1). A positive sodium-channel blocker test was associated with a significantly higher event rate in symptomatic patients (P = .01) but not in asymptomatic individuals (P = .18). No events occurred among asymptomatic individuals with an incidental nondiagnostic Br-ECG.
Conclusions:
In asymptomatic individuals with a nondiagnostic Br-ECG, the incidence of events is low regardless of the sodium-channel blocker test result while in symptomatic patients a positive sodium-channel blocker test result is associated with an adverse arrhythmic outcome and may contribute to risk stratification.
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