Clinical Electrophysiology -> SCA Risk Assessment: -> Other Noninvasive Techniques D-PO04 - Poster Session IV (ID 15) Poster

Abstract

Background: Brugada syndrome (BrS) is an inherited channelopathy defined by a typical ST elevation in the electrocardiogram (ECG), in the absence of secondary causes. However, diagnosis can be challenging due to the dynamic nature of ST elevation. High right precordial (HRP) leads, as well as drug challenge, can be used to improve the detection of BrS. Data regarding the utility of an optimized tool during stress testing (ST) to detect spontaneous pattern were not yet studied.
Objective: We aimed to determine if stress testing using HRP leads (ST-HRP) can unmask type 1 Brugada pattern and increase diagnostic yield compared to standard approach.
Methods: Fifty-three out of 136 patients from a Brazilian cohort of type 1 BrS underwent ST-HPL. Bruce and Ellestad protocols were performed with V1 and V2 leads in the 4th, 3rd and 2nd intercostal spaces (IC S). ST segment elevation was observed in the resting period, during maximal exercise and in passive recovery phase with horizontal dorsal decubitus position. We compared the detection of type 1 Brugada pattern in standard versusHRP leads during stress testing. McNemar test was used with the IBM SPSS for Windows version 22.0. Significance level was set at p< 0.05.
Results: Patients were predominantly male (41/53; 77.4%), mean age 51±13 y.o., with spontaneous type 1 Brugada pattern (39/53, 73.6%), with an intermittent ST elevation. Only 11/53 patients (20.8%) had type 1 pattern in the resting phase using HRP leads. During the recovery phase of the exercise test using the ST-HRP a positive result for the Brugada type I pattern was statistically greater than with standard right lead positioning (45.3% vs. 28.3%, p = 0.022). This was also true when joining both the stress and recovery phases (45.1% vs. 29.4%, p = 0.039). At the same time, alterations were found to be statistically more positive with the stress test relative to the rest ECG, both using the standard (29.4% vs. 7.8%, p= 0.001) and the HRP leads positioning (46.2% vs. 19.2%, p < 0.001).
Conclusion: Stress testing using high right precordial leads with horizontal dorsal decubitus position in passive recovery provides an opportunity to unmask type 1 Brugada pattern and this might raise the utility of this protocol, a priceless and original tool to increase diagnostic yield in this population.
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