Does difference in ICD indication result in a difference in inappropriate shock risk?

Brugada syndrome is a heritable cause of fatal ventricular arrhythmias in people with otherwise structurally normal hearts. It is diagnosed by the identification of a characteristic ECG pattern in association with certain risk factors [1]. Some risk factors are clinical events likely to be precipitated by ventricular arrhythmias, such as syncope and agonal respirations during sleep. Such patients with suspected or documented ventricular arrhythmias have a high risk of recurrent ventricular arrhythmias and meet indications for ICD implantation for secondary prevention [2]. A second population of patients diagnosed with Brugada syndrome had no clinical events, but either have a family history of sudden cardiac death or have inducible ventricular arrhythmias. The best course of management for this second group of patients who are asymptomatic has been difficult to determine. In making a decision regarding ICD implantation, providers and patients must weigh benefits and burdens of each option. The risk of ventricular fibrillation and sudden cardiac death in asymptomatic patients has been difficult to quantify; the approach to risk stratification in asymptomatic patients with suspected Brugada syndrome remains controversial. Bonny et al. focus on the burdens of ICD implantation, comparing 33 symptomatic and 18 asymptomatic patients implantedwith an ICD for Brugada syndrome over a 14 year period [3]. The symptomatic secondary prevention group had 11 patients receive appropriate shocks and 2 patients receive inappropriate shocks. The primary prevention group received no appropriate shocks and 5 patients received inappropriate shocks [3]. This finding is in agreement with prior studies finding low risks for ventricular arrhythmia occurrence in asymptomatic Brugada syndrome patients [4]. This study identifies a trend toward more inappropriate shocks in patients with Brugada syndrome undergoing ICD implantation for primary prevention (27.8% versus 6.1%, p 1⁄4 0.08). There were 2 patients with inappropriate shocks due to lead malfunction in each group; additionally, the asymptomatic group had 2 patients inappropriately shocked for rapid ventricular rates during atrial fibrillation, and 1 patient inappropriately shocked for T wave oversensing. Other ICD related complications include pocket infection in 2 (4%), endocarditis in 1 (2%), and device-related depression in 2 (4%). One case of depression was determined to be secondary to inappropriate shocks in a patient who was asymptomatic prior to ICD implantation [3]. There were no statistically significant differences among the