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The Utility of Exercise Testing in Risk Stratification of Asymptomatic Patients With Type 1 Brugada Pattern
Author(s) -
SUBRAMANIAN MUTHIAH,
PRABHU MUKUND A.,
HARIKRISHNAN MADHAVANKUTTY SANTHAKUMARI,
SHEKHAR SARITHA S.,
PAI PRAVEEN G.,
NATARAJAN KUMARASWAMY
Publication year - 2017
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/jce.13205
Subject(s) - medicine , brugada syndrome , asymptomatic , cardiology , risk stratification , sudden cardiac death , ventricular fibrillation , cohort
Risk Stratification in Type 1 Brugada Pattern Introduction Risk 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 Results Treadmill 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). Conclusions Exercise 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.