7.9.1.3 Brugada Syndrome
| COR | LOE | Recommendations |
|---|---|---|
| I | B-NR |
|
| I | B-NR | |
| I | B-NR | |
| I | B-NR | |
| IIa | B-NR | |
| IIb | B-NRSR | |
| IIb | C-EO |
and.
Synopsis
Refer to the “Systematic Review for the 2017 ACC/AHA/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death” for the complete systematic evidence review for additional data and analyses (S7.9.1.3-15). The results from the question “For asymptomatic patients with Brugada syndrome, what is the association between an abnormal EP study and SCD and other arrhythmia endpoints? (Part 1)” and the writing committee’s review of the totality of the literature were used to frame decision-making. Recommendations that are based on a body of evidence that includes the systematic review conducted by the ERC are denoted by the superscript SR (e.g., LOE: B-R SR).
Factors identified as potential triggers of VF and SCA in Brugada syndrome include some psychotropic medications, and anesthetic agents, cocaine, excessive alcohol intake, and fever (www.brugadadrugs.org) [1], [2]. These agents should be avoided, and fever warrants early and aggressive measures to reduce temperature (S7.9.1.3-23).
Recommendation-Specific Supportive Text
- 1.
The risk of major adverse cardiac events in asymptomatic patients without spontaneous type 1 electrocardiographic changes of Brugada syndrome ( ), or with only medication-induced electrocardiographic changes, is low [1], [2], [3], [4], [5]. A positive family history of Brugada syndrome or SCA is not a significant predictor of adverse events in Brugada syndrome [1], [2], [3], [4]. Implantation of an ICD in an asymptomatic patient without a spontaneous type 1 Brugada electrocardiographic has not been shown to confer any benefit.
- 2.
Brugada syndrome is characterized by coved ST elevation in leads V1 or V2 positioned in the second, third, or fourth intercostal space either spontaneously or induced by administration of a sodium channel–blocking drug in the absence of other causes of ST elevation (S7.9.1.3-24) and negative T waves in the right precordial leads, and is associated with syncope or SCA due to VF, predominantly in young males, although it has been reported in all age groups. The type 1 Brugada ECG with coved ST elevation in right precordial leads may be present spontaneously, during fever or vagotonic states, or after medication challenge with sodium channel blockers. QRS complex fractionation is seen in a minority of patients. Patients with spontaneous coved type ST elevation and a history of syncope or prior SCA are at the highest risk for potentially lethal VA. ICD implantation has been shown to reduce mortality in symptomatic patients with Brugada syndrome [1], [2].
- 3.
Ablation of abnormal areas of epicardial late activation in the RV can suppress recurrent VA as shown in a small number of patients [1], [2], [3], [4]. In these reports, the spontaneous type 1 Brugada pattern on ECG may be eliminated in >75% of patients, and recurrences of VT/VF are markedly reduced [1], [2], [3]. Experience and follow-up after ablation are limited, and an ICD for patients who have had syncope or SCA is recommended. A series of patients with Brugada syndrome treated with quinidine had no deaths during a mean follow-up of over 9 years, although adverse effects of quinidine were reported in 38% of patients, these authors felt that quinidine could be used as an alternative to the ICD in selected patients (S7.9.1.3-7).
- 4.
Observational studies show that quinidine can suppress VF storm in patients with Brugada syndrome, and a low risk of arrhythmia was observed in a long-term observational study (681). No patient treated with quinidine experienced SCD. Adverse effects of quinidine occur in up to 37% of patients. Catheter ablation targeting the epicardial right ventricular areas of abnormality has also been shown to reduce recurrent VF episodes and normalize the ECG (682, 684, 685).
- 5.
Administration of procainamide, flecainide, or ajmaline may be useful to provoke type 1 ST elevation in patients suspected to have Brugada syndrome as a cause of symptoms but who do not have a type 1 electrocardiographic pattern at baseline. Medication challenge should be terminated with the development of VA, marked QRS widening, or type 1 Brugada electrocardiographic pattern [1], [2]. The use of high electrocardiographic electrode positioning in the second and third interspaces for electrocardiographic recording improves detection of a type 1 Brugada ECG (S7.9.1.3-29). Asymptomatic patients with a family history of Brugada syndrome may be offered sodium channel blocker challenge for diagnostic evaluation, although a positive test does not require chronic therapy due to a low risk in this setting (S7.9.1.3-12). In asymptomatic patients with type 1 Brugada electrocardiographic findings, medication challenge does not offer additional diagnostic value.
- 6.
Polymorphic VT/VF induced by programmed stimulation has been associated with an increased risk of VA in some patients with spontaneous type 1 Brugada ECG (S7.9.1.3-13). The specificity of programmed stimulation for assessing risk decreases with the inclusion of triple extrastimuli [1], [2]. The value of programmed stimulation in asymptomatic patients with spontaneous type 1 Brugada ECGs has been the subject of multiple studies [1], [2], [3], [4]. A report found that the prognostic value has decreased over time, possibly as patients with less severe phenotypes have been recognized and studied (S7.9.1.3-1). Some experts use the results of programmed ventricular stimulation for informing shared decision-making in consideration of the ICD. In symptomatic patients with Brugada syndrome, programmed ventricular stimulation for risk stratification does not add anything to the evaluation of the patients as an ICD is warranted [1], [2], [3].
- 7.
The yield of genetic testing in phenotype positive patients is approximately 20% to 30% in Brugada syndrome [1], [2], [3], [4], [5], [6]. SCN5A variants account for most of this subset of genotype positive Brugada syndrome. However, 2% to 10% of otherwise healthy individuals host a rare variant of SCN5A[1], [2]. A negative genetic test does not exclude the diagnosis of Brugada syndrome, which is usually based on electrocardiographic and clinical characteristics. Risk stratification is based on symptoms and clinical findings (S7.9.1.3-32); genotype status is not correlated with the risk of adverse events [1], [2], [3], [4]. Identification of a pathogenetic mutation may help facilitate recognition of carrier status in family members, allowing for lifestyle modification and potential treatment.
- 8.
Factors identified as potential triggers of VF and SCA in Brugada syndrome include some psychotropic medications, and anesthetic agents, cocaine, excessive alcohol intake, and fever (www.brugadadrugs.org) [1], [2]. These agents should be avoided and fever warrants early and aggressive measures to reduce temperature (S7.9.1.3-23).