Why the study?
Microstructural epicardial RVOT abnormalities may provide the arrhythmia substrate in Brugada syndrome, but the clinical implications of an abnormal endocardial substrate identified by high-density electroanatomical mapping remained to be evaluated.
Does endocardial high-density electroanatomical mapping identify high-risk patients with Brugada syndrome?
Does endocardial high-density electroanatomical mapping identify high-risk patients with Brugada syndrome?
Extensive endocardial electroanatomical abnormalities identified by high-density mapping can distinguish high-risk symptomatic Brugada syndrome patients from asymptomatic ones, offering a potential new risk stratification tool.
Extensive endocardial abnormalities on HDEAM may identify high-risk BrS; leaves open prospective validation for risk stratification.
Introduction Microstructural abnormalities at the epicardium of the right ventricular outflow tract (RVOT) may provide the arrhythmia substrate in Brugada syndrome (BrS). Endocardial unipolar electroanatomical mapping allows the identification of epicardial abnormalities. We evaluated the clinical implications of an abnormal endocardial substrate as perceived by high‐density electroanatomical mapping (HDEAM) in patients with BrS. Methods Fourteen high‐risk BrS patients with aborted sudden cardiac death (SCD) (12 males, mean age: 41.9 ± 11.8 years) underwent combined endocardial‐epicardial HDEAM of the right ventricle/RVOT, while 40 asymptomatic patients (33 males, mean age: 42 ± 10.7 years) underwent endocardial HDEAM. Based on combined endocardial‐epicardial procedures, endocardial HDEAM was considered abnormal in the presence of low voltage areas (LVAs) more than 1 cm 2 with bipolar signals less than 1 mV and unipolar signals less than 5.3 mV. Programmed ventricular stimulation (PVS) was performed in all patients. Results The endocardial unipolar LVAs were colocalized with epicardial bipolar LVAs ( p = .0027). Patients with aborted SCD exhibited significantly wider endocardial unipolar ( p < .01) and bipolar LVAs ( p < .01) compared with asymptomatic individuals. A substrate size of unipolar LVAs more than 14.5 cm 2 (area under the curve [AUC]: 0.92, p < .001] and bipolar LVAs more than 3.68 cm 2 (AUC: 0.82, p = .001) distinguished symptomatic from asymptomatic patients. Patients with ventricular fibrillation inducibility (23/54) demonstrated broader endocardial unipolar ( p < .001) and bipolar LVAs ( p < .001) than noninducible patients. The presence of unipolar LVAs more than 13.5 cm 2 (AUC: 0.95, p < .001) and bipolar LVAs more than 2.97 cm 2 (AUC: 0.78, p < .001) predicted a positive PVS. Conclusion Extensive endocardial electroanatomical abnormalities identify high‐risk patients with BrS. Endocardial HDEAM may allow risk stratification of asymptomatic patients referred for PVS.
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Letsas et al. (2021) studied this question.
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