Abstract 2142: Diagnostic and Prognostic Value of Augmented ST-Segment Elevation at Exercise Testing in Patients with Brugada Syndrome
Background: It has been reported that ST-segment elevation was augmented at early recovery phase or at peak exercise during exercise testing in some patients with Brugada syndrome (BrS), but its diagnostic and prognostic value has not fully been clarified.
Methods: Treadmill exercise testing (TMT) was conducted in 93 patients (pts) with BrS (22 documented VF, 31 syncope alone, and 40 asymptomatic; 91 males, 46±14 years) and 22 healthy control subjects (20 males, 48±14 years, 11 with incomplete right bundle branch block (RBBB) and 4 with complete RBBB).
Results: The augmentation of ST-segment elevation ≥0.05mV in V1-V3 leads compared with that before exercise was observed at early recovery phase (1– 4 minutes at recovery phase) in 32 BrS pts (34%, Group1), at peak exercise in 8 BrS pts (9%, Group 2), but not in either the remaining 53 BrS pts (57%, Group 3) or 22 control subjects. There were no significant differences among the 3 BrS groups in the baseline clinical (age, gender, family history of sudden death, SCN5A mutation), electrocardiographic (PR, QRS duration, QTc interval and ST amplitude), and electrophysiologic (AH, HV interval, and VF induction) variables except for the positive ratio of signal averaged ECG (87%, 48%, 63%; P= 0.001). No significant difference was observed in the proportion of previous cardiac events (VF/syncope/asymptomatic; 6/12/14, 0/3/5, 16/16/21, respectively for Group 1, 2, and 3). During 76.0, 74.8, and 52.0 months follow-up, VF occurred in 12/32 (38%) pts of Group1, 0/8 (0 %) pts of Group2, and 10/53 (19%) pts of Group3. Augmentation of ST-segment elevation at early recovery phase was a significant and an independent predictor for subsequent VF occurrence (12/32 (38%) in Group1 vs. 10/61 (16%) in Group2 and 3; hazard ratio [HR]= 1.68; P=0.014), especially in 31 pts with a history of syncope alone (6/12 (50%) in Group1 vs. 1/19 (5%) in Group2 and 3; HR=3.44; P=0.004).
Conclusions: Our data suggest that augmentation of ST-segment elevation at early recovery phase during exercise testing can be a predictor of poor prognosis in patients with Brugada syndrome, especially in those with a history of syncope alone.