Ultra-high-frequency ECG unmasks concealed Brugada syndrome
K Saleh, R Smisek, H Wong, J Mohal, A Naraen, J Samways, C Sharma, P Leinveber, P Jurak, J Ormerod, L Wong, J Ware, Z Whinnett, A Varnava, A ArnoldAbstract
Background
Brugada syndrome (BrS) is diagnosed by detection of the characteristic type 1 ECG pattern, but this may be absent on the resting 12-lead ECG due to the dynamic nature of the BrS substrate. Ultra-high-frequency ECG (UHF-ECG) enables the analysis of high frequency ECG signals (>150Hz), offering detailed spatio-temporal ventricular activation information beyond conventional 12-lead ECG. We hypothesised that UHF-ECG could reveal low amplitude, fractionated signals in the right ventricular outflow tract (RVOT), suggestive of Brugada syndrome, even in the concealed phenotype.
Purpose
To assess whether UHF-ECG can distinguish concealed Brugada syndrome from healthy volunteers.
Methods
We prospectively recruited 107 participants (65.4% male, median age 33) for 10-minute UHF-ECG recordings using a high praecordial lead configuration (V1 and V2 positioned at the 2nd, 3rd and 4th intercostal spaces). Participants included 52 concealed Brugada patients (absent resting type 1 ECG pattern), 14 manifest Brugada patients (type 1 ECG pattern present at rest), 34 healthy volunteers, and 5 ajmaline negative patients with no history of aborted SCD. Recordings were acquired using a specialised UHF-ECG acquisition device. For each lead, we calculated the root mean square (RMS) and the number of peaks within the 401–701 Hz frequency band of the QRS complex.
Results
Classification accuracy metrics are presented in Table 1. The averaged RMS values across all V1 and V2 leads were significantly lower in both Brugada groups compared with healthy and ajmaline negative participants (Figure 1A). This difference was most marked in V1 and V2 at the 2nd intercostal space (Youden index 0.66 and 0.65 respectively). The number of UHF peaks was higher in both Brugada groups (Figure 1B), with significant differences in V1 at the 3rd and 4th intercostal spaces.
Conclusion
Our findings indicate that UHF-ECG parameters such as RMS and numbers of peaks are useful metrics to discriminate concealed Brugada patients from healthy volunteers. Furthermore, these results suggest that UHF-ECG in a high praecordial configuration may provide a sensitive, practical and non-invasive method for detecting subtle conduction abnormalities of the RVOT. These findings support a role for UHF-ECG in Brugada screening and diagnostic evaluation, warranting further validation in larger cohorts.Figure 1Table 1