Key result
Fragmented QRS in the inferior region was associated with an increased risk of ventricular fibrillation in patients with Brugada syndrome (HR 3.9; 95% CI 1.9-8.5).
Why the study?
Does the distribution of fragmented QRS complexes predict the occurrence of ventricular fibrillation in patients with Brugada syndrome?
Cohort (n=456)
Does the distribution of fragmented QRS complexes predict the occurrence of ventricular fibrillation in patients with Brugada syndrome?
Hazard Ratio: 3.9 (95% CI 1.9–8.5)
The presence and specific distribution of fragmented QRS complexes, particularly in multiple regions, are associated with a higher risk of ventricular fibrillation in patients with Brugada syndrome.
May support risk stratification in Brugada syndrome; hypothesis-generating and requires prospective validation before guiding management.
BACKGROUND: Fragmented QRS complexes (fQRS) in the right precordial leads are associated with occurrence of ventricular fibrillation (VF) in Brugada syndrome. Recently, epicardial mapping has revealed abnormal electrograms at the right ventricular (RV) outflow tract and inferior region of the right ventricle. fQRS may reflect the extent of the area of abnormal potentials, but whether the distribution of fQRS has prognostic value is not known. METHODS AND RESULTS: We evaluated the existence of fQRS in 456 patients with Brugada syndrome, including 117 patients with syncope and 23 patients with VF. The region of fQRS was defined as inferior (II, III, and aVF), lateral (I, aVL, and V5 and V6), anterior (V3 and V4), RV (V1 and V2), and RV outflow tract (V1 and V2 at the third intercostal space). fQRS were present in 229 patients (RV outflow tract in 175, inferior in 135, RV in 90, and lateral in 16 patients). During follow-up (mean 91 months), 39 patients experienced VF. In univariable analyses, fQRS in any distribution and fQRS in each region excluding the RV were associated with VF. Multivariable analysis showed that fQRS in the inferior (hazard ratio, 3.9; confidence interval, 1.9-8.5), lateral (hazard ratio, 3.5; confidence interval, 1.2-8.2), and RV outflow tract (hazard ratio, 2.5; confidence interval, 1.2-5.6) were associated with VF events. The presence of multiple regions of fQRS was associated with worse prognosis. CONCLUSIONS: The distribution of fQRS is associated with prognosis in Brugada syndrome, further supporting the association of fQRS and arrhythmia substrate.
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Morita et al. (2017) conducted a cohort in Brugada syndrome (n=456). Fragmented QRS complexes (fQRS) vs. Absence of fQRS was evaluated on Ventricular fibrillation (VF) (HR 3.9, 95% CI 1.9-8.5). Fragmented QRS in the inferior region was associated with an increased risk of ventricular fibrillation in patients with Brugada syndrome (HR 3.9; 95% CI 1.9-8.5).
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