Predictors of inappropriate shock in Brugada syndrome patients with a subcutaneous implantable cardiac defibrillator

Background Subcutaneous implantable cardioverter defibrillators (S-ICDs) avoid complications secondary to transvenous leads, but inappropriate shocks (ISs) are frequent. Furthermore, IS data from patients with Brugada syndrome (BrS) with an S-ICD are scarce. Objective We aimed to establish the frequency and predictors of IS in this population. Methods We analyzed the clinical and electrocardiographic characteristics, automated screening test data, device programming, and IS occurrence in adult patients with BrS with an S-ICD. Results Thirty-nine patients were enrolled (69% male, mean age at diagnosis 46 +/- 13 years, mean age at implantation 48 +/- 13 years). During a mean follow-up of 26 +/- 21 months, 18% patients experienced IS. Patients with IS were younger at the time of diagnosis (36 +/- 8 vs. 48 +/- 13 years, p = .018) and S-ICD implantation (38 +/- 9 vs. 50 +/- 23 years, p = .019) and presented with spontaneous type 1 Brugada electrocardiogram pattern more frequently at diagnosis or during follow-up (71% vs. 25%, p = .018). During automated screening tests, patients with IS showed lower QRS voltage in the primary vector in the supine position (0.58 +/- 0.26 vs. 1.10 +/- 0.35 mV, p = .011) and lower defibrillator automated screening score in the primary vector in the supine (123 +/- 165 vs. 554 +/- 390 mV, p = .005) and standing (162 +/- 179 vs. 486 +/- 388 mV, p = .038) positions. Age at diagnosis was the only independent predictor of IS (hazard ratio = 0.873, 95% confidence interval: 0.767-0.992, p = .037). Conclusion IS was a frequent complication in patients with BrS with an S-ICD. Younger age was independently associated with IS. A more thorough screening process might help prevent IS in this population.

Automated summary

In patients with Brugada syndrome using subcutaneous implantable cardioverter defibrillators (S-ICDs), inappropriate shocks (IS) are a frequent and adverse complication. Younger age is independently associated with IS, suggesting that a more thorough screening process may help prevent IS in this population.