Electroanatomic and Pathologic Right Ventricular Outflow Tract Abnormalities in Patients With Brugada Syndrome

J Am Coll Cardiol. 2018 Dec 4;72(22):2747-2757. doi: 10.1016/j.jacc.2018.09.037.

Abstract

Background: The prevalence and significance of structural abnormalities in Brugada syndrome (BrS) are still largely debated.

Objectives: The authors investigated the relationship between genetic background, electroanatomic abnormalities, and pathologic substrate in BrS.

Methods: They performed 3-dimensional electroanatomic unipolar and bipolar mapping in 30 patients with BrS. Twenty patients underwent 3-dimensional electroanatomic unipolar and bipolar mapping-guided right ventricular outflow tract (RVOT) endomyocardial biopsy. Programmed ventricular stimulation and genetic analysis were performed in all patients.

Results: Low-voltage areas (LVAs) were observed at unipolar map in 93% of patients and at bipolar map in 50% of cases. Unipolar LVAs were always larger than bipolar LVAs, were always colocalized, and in all cases included RVOT. Disease-causing mutations were detected in 10 (33%) patients. Programmed ventricular stimulation was positive in 16 cases (53%). In 75% of patients, RVOT histology showed pathologic findings with myocardial inflammation in 80% of them. Among patients with abnormal bipolar map submitted to endomyocardial biopsy, 9 (81%) showed evidence of myocardial inflammation. Conversely, bipolar map was abnormal in 83% of patients with myocardial inflammation. Myocardial inflammation was also more prevalent among inducible patients (83% vs. 25% in noninducible; p = 0.032).

Conclusions: BrS is characterized by electroanatomical and structural abnormalities localized to RVOT with a gradient of the pathologic substrate from epicardium to endocardium possibly driven by myocardial inflammation. These findings reclassify BrS as a combination of structural and electrical defects opening the way to new risk stratification and therapeutic strategies.

Keywords: Brugada syndrome; electroanatomic mapping; endomyocardial biopsy; genetic analysis; myocardial inflammation; sudden cardiac death.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Body Surface Potential Mapping / methods*
  • Brugada Syndrome / diagnostic imaging*
  • Brugada Syndrome / physiopathology*
  • Brugada Syndrome / therapy
  • Defibrillators, Implantable
  • Electrocardiography / methods
  • Female
  • Follow-Up Studies
  • Humans
  • Imaging, Three-Dimensional / methods*
  • Male
  • Middle Aged
  • Ventricular Outflow Obstruction / diagnostic imaging*
  • Ventricular Outflow Obstruction / physiopathology*
  • Ventricular Outflow Obstruction / therapy