The Utility of Exercise Testing in Risk Stratification of Asymptomatic Patients With Type 1 Brugada Pattern

• DOI: 10.1111/jce.13205
• Publication Date: 2017-03-19T05:59:17Z
• Authors: MUTHIAH SUBRAMANIAN; MUKUND A. PRABHU; MADHAVANKUTTY SAN...; SARITHA S. SHEKHAR; PRAVEEN G. PAI; KUMARASWAMY NATAR...
• Keywords: Adult; Male; Time Factors; Kaplan-Meier Estimate; Middle Aged; Risk Assessment; Disease-Free Survival; 3. Good health; Electrocardiography; 03 medical and health sciences; Death, Sudden, Cardiac; Logistic Models; 0302 clinical medicine; ROC Curve; Predictive Value of Tests; Risk Factors; Area Under Curve; Case-Control Studies; Asymptomatic Diseases; Exercise Test; Humans; Female; Brugada Syndrome

Risk Stratification in Type 1 Brugada PatternIntroductionRisk stratification of asymptomatic patients with a Brugada type 1 ECG pattern remains an unresolved clinical conundrum. In contrast to provocative pharmacological testing in Brugada syndrome, there is limited data on the role of exercise stress testing as a risk stratification modality. The objective of this study was to evaluate the utility of exercise testing in asymptomatic patients with type 1 Brugada pattern to prognosticate major arrhythmic events (MAE) during follow‐up.Methods and ResultsTreadmill exercise testing was conducted for 75 asymptomatic patients with type 1 Brugada pattern and for 88 healthy control subjects. The clinical end point of MAE was defined as the occurrence of sudden cardiac death (SCD) or resuscitated ventricular fibrillation (VF). During a follow‐up of 77.9 ± 28.9 months, eight MAE occurred (five VF and three SCD). Multivariate Cox regression analysis showed that the following were independent predictors of MAE in asymptomatic patients with a type 1 Brugada pattern: increase in S wave upslope duration ratio >30% at peak exercise (HR 1.35, 95% CI 1.08–10.97, P = 0.023), augmentation of J point elevation in lead aVR >2 mm in late recovery (HR 1.88, 95% 1.21–15.67, P = 0.011), and delayed HR recovery (HR 1.14, 95% CI 1.06–18.22, P = 0.042). A high‐risk cohort was identified by the final step‐wise regression model with good accuracy (specificity = 98.4%, sensitivity = 62.5%) and discriminative power (AUC = 0.93, 95% CI 0.89–0.96, P = 0.002). Kaplan–Meier analysis revealed increasing MAE in subjects with one, two, or three predictors, respectively (log rank P < 0.001).ConclusionsExercise testing in asymptomatic patients with type 1 Brugada pattern aids in identification of high‐risk patients and provides a unique window of opportunity for early intervention.