Inappropriate implantable cardioverter-defibrillator shocks in Brugada syndrome: Pattern in primary and secondary prevention

Abstract

Background: Inappropriate implantable cardioverter-defibrillator (ICD) shocks is a common complication in Brugada syndrome. However, the incidence in recipients of ICD for primary and secondary prevention is unknown.

Method and results: We compared the rate of inappropriate shocks in patients with Brugada syndrome that had an ICD for primary and secondary prevention. We studied 51 patients, 86.5% of whom were males. Their mean age at diagnosis was 47 ± 11 years. Eighteen (35%) were asymptomatic, while 25 (49%) experienced syncope prior to implantation. Eight (16%) patients were resuscitated from ventricular fibrillation before implantation. During a mean follow-up of 78 ± 46 months, none of the asymptomatic patients experienced appropriate therapy, whereas 21.6% of symptomatic patients had ≥1 shock. Inappropriate shock occurred in 7 (13.7%) patients, with a mean IS of 6.57 ± 6.94 shocks per patient occurring 16.14 ± 10.38 months after implantation. There was a trend towards higher incidence of inappropriate shock in the asymptomatic group (p = 0.09). The interval from implantation to inappropriate shock occurrence was 13.91 ± 12.98 months. The risk of IS at 3 years was 13.7%, which eventually plateaued over the time.

Conclusion: Inappropriate shock is common in Brugada syndrome during the early periods after an ICD implantation, and seems to be more likely in asymptomatic patients. This finding may warrant a review of the indications for ICD implantation, especially in the young and apparently healthy population of patients with Brugada syndrome.

Keywords: Brugada syndrome; Implantable cardioverter-defibrillator; Inappropriate shock.

Fig. 1

Diagnostic ECG pattern of Brugada syndrome. Spontaneous coved-type S-T elevation in right precordial leads (mostly in V₁ and V₂ rather than V₃) is the hallmark of Brugada syndrome.

Fig. 2

Kaplan-Meier curve of inappropriate shocks in BrS patients who underwent ICD implantation for primary and secondary prevention. Given the low prevalence of Brugada syndrome in the general population, the difference between both groups was calculated using two-sided t-test α-level of 10%.

Fig. 3

Pace-sense failure related to inappropriate shock. A 54-year old asymptomatic female in whom an implantable cardioverter-defibrillator was implanted have experienced 17 inappropriate shocks. Pace-sense insulation breach of a Sprint Fidelis lead (Medtronic, Mineapolis, MN) led to oversensing low-voltage nonphysiological signals.