Key result
Single premature RV stimulation converts type-1 to type-2 ECGs in ~83% of Brugada syndrome patients.
Why the study?
Does premature stimulation of the right ventricle alter ECG morphology in patients with Brugada syndrome?
Observational (n=41)
Does premature stimulation of the right ventricle alter ECG morphology in patients with Brugada syndrome?
Premature right ventricular stimulation during electrophysiological study can unmask typical Brugada ECG patterns in patients with concomitant complete right bundle branch block and convert type-1 to type-2 patterns.
May aid ECG diagnosis in Brugada syndrome with CRBBB; hypothesis-generating and requires prospective validation before clinical use.
BACKGROUND: In Brugada syndrome (BrS), it has been reported that delayed activation in the RV is related to the development of type-1 ECG, which is more critical than type-2. On the other hand, the coexistence of complete right bundle-branch block (CRBBB), which also causes delayed activation in the RV, sometimes makes typical BrS ECG misleading. We hypothesized that premature stimulation of the RV can unmask the influence of delayed activation in the RV and convert the morphology of ECG in BrS patients. METHODS AND RESULTS: In 35 BrS patients with type-1 ECG including 8 patients with concomitant CRBBB and 6 control subjects with CRBBB, progressively premature single stimulations were delivered from the RV apex on electrophysiological study. Then we evaluated QRS morphology of fusion beats created by single premature stimulation in each patient. In 29 (83%) of 35 of the BrS patients, conversion from type-1 to type-2 ECG was observed during the process of single premature stimulation. Additionally, in all 8 BrS patients with concomitant CRBBB, type-1 or type-2 BrS ECG was revealed by premature stimulation with relief of CRBBB. These findings were not observed in any of the control subjects with CRBBB. CONCLUSION: Single premature stimulation of the RV converts ECG from type-1 to type-2 in most BrS cases and unmasks type-1 ECG in all BrS cases with CRBBB. Our results could suggest that type-1 ECG is associated with delayed activation of the RV compared with type-2 ECG.
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Nakagawa et al. (2017) conducted an observational in Brugada syndrome (n=41). Premature single stimulations from the RV apex vs. Control subjects with CRBBB was evaluated on Conversion from type-1 to type-2 ECG. Single premature stimulation of the RV converted ECG from type-1 to type-2 in 83% of Brugada syndrome patients and unmasked type-1 ECG in all 8 patients with concomitant CRBBB.
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