The β-angle can help guide clinical decisions in the diagnostic work-up of patients suspected of Brugada syndrome: a validation study of the β-angle in determining the outcome of a sodium channel provocation test. Issue 12 (14th June 2021)

• Record Type: Journal Article
• Authors: van der Ree, Martijn H; Vendrik, Jeroen; Verstraelen, Tom E; Kors, Jan A; Amin, Ahmad S; Wilde, Arthur A M; Tan, Hanno L; Postema, Pieter G
• Is Part Of: Europace. Volume 23:Issue 12(2021)
• Page Start: 2020
• Page End: 2028
• Publication Date: 2021-06-14
• Subjects: Brugada syndrome -- Electrocardiographic characteristics -- β-angle -- Diagnostic characteristics; Arrhythmia -- Treatment -- Periodicals; Cardiac pacing -- Periodicals; Catheter ablation -- Periodicals; Heart -- Physiology -- Periodicals; Electrophysiology -- Periodicals; 617.4120645
• DOI: 10.1093/europace/euab128
• Languages: English
• ISSNs: 1099-5129

Abstract

Abstract: Aims: In patients with Brugada syndrome (BrS) but without spontaneous Type-1 electrocardiogram, several electrocardiographic characteristics have been studied, including the β-angle. Previous studies suggested that the β-angle might be useful in distinguishing BrS-patients from patients with only suggestive repolarization patterns without performing sodium channel blocker provocation testing. In this study, we aimed to determine the diagnostic value of the β-angle in patients suspected of BrS. Methods and results: A large cohort ( n = 1430) of consecutive patients who underwent provocation testing was evaluated. β-angles were measured in leads V1, V2, and their corresponding positions over the second and third intercostal space. Receiver-operating characteristic curves were constructed and the diagnostic accuracy of previously reported β-angle cut-offs were calculated and evaluated. The importance of the β-angle for predicting the provocation test outcome was determined using a prediction model constructed with logistic regression. The optimum β-angle cut-off in our cohort for ruling out a positive provocation test was 15°; sensitivities were 80–98% and negative predictive values were 79–96% among the right precordial leads. Previously reported β-angle cut-offs performed less well, indicated by lower Youden indices. In the optimism-corrected prediction model [ C -statistic: 0.78 (95% CI: 0.75–0.81)], the β-angle had large value ( Z -score: 2.1–10.3) and aided construction of a nomogram to predict test outcome. Conclusion: To predict the outcome of provocation testing for BrS, the β-angle alone does not demonstrate strong diagnostic characteristics. However, the β-angle is an important variable to predict provocation test outcome and thus has added value.