Abstract 12170: Paced-QRS fragmentation as a Novel Predictor for Ventricular Fibrillation in Patients With Brugada Syndrome

Abstract

Introduction: In patients with Brugada syndrome, conduction abnormalities could serve as a substrate for ventricular fibrillation (VF) and fragmented QRS appears to be a predictor of VF. Hypothesis: Therefore, we hypothesized that right ventricular apical pacing (RVP) could enhance or unmask the QRS fragmentation in the right precordial leads and paced-QRS fragmentation might predict a risk of VF in patients with Brugada syndrome. Methods: Eighteen consecutive male patients who underwent ICD implantation were categorized into 10 patients with spontaneous VF (group VF(+)) and 8 patients without VF (group VF(-)). The number of spikes within the QRS complex in leads V1-V2 and the duration of QRS fragmentation in lead V1 were evaluated (with 0.05-150 Hz filters) during both sinus rhythm (SR) and during RVP using ICD at VVI 80 bpm or 110 bpm. Results: Sum of spikes in lead V1-V2 was not significantly different between groups VF(+) and VF(-) during SR; however, it was greater in VF(+) than VF(-) during RVP at VVI 80 bpm (7.0±2.8 vs 2.9±5.2, p = 0.04) and VVI 110 bpm (10.7±3.7 vs 2.4±3.2, p = 0.01). The duration of QRS fragmentation in lead V1 was longer in VF(+) than VF(-) at VVI 110 bpm (173±32 ms vs 45±44 ms, p = 0.006). In VF(+), sum of spikes (V1-V2) was higher and the duration of QRS fragmentation (V1) was longer at VVI 110 bpm compared to VVI 80 bpm (10.1±3.7 vs 7.0±2.8, p = 0.02 and 173±32 ms vs 111±39 ms, p = 0.02, respectively). According to ROC analysis, sum of spikes ≥ 3.5 most accurately predicted spontaneous VF with sensitivity of 100% and specificity of 87.5%. Conclusions: Right ventricular apical pacing enhanced or unmasked QRS fragmentation in the right precordial leads in patients with Brugada syndrome. Therefore, paced-QRS fragmentation could be a novel predictor for spontaneous VF in patients with Brugada Syndrome.