Predictors of late arrhythmic events after generator replacement in Brugada syndrome treated with prophylactic ICD

Abstract

Introduction: Predictors of late life-threatening arrhythmic events in Brugada syndrome (BrS) patients who received a prophylactic ICD implantation remain to be evaluated. The aim of the present long-term multicenter study was to assess the incidence and clinical-electrocardiographic predictors of late life-threatening arrhythmic events in BrS patients with a prophylactic implantable cardioverter defibrillator (ICD) and undergoing generator replacement (GR).

Methods: The study population included 105 patients (75% males; mean age 45 ± 14years) who received a prophylactic ICD and had no arrhythmic event up to first GR.

Results: The median period from first ICD implantation to last follow-up was 155 (128-181) months and from first ICD Implantation to the GR was 84 (61-102) months. During a median follow-up of 57 (38-102) months after GR, 10 patients (9%) received successful appropriate ICD intervention (1.6%/year). ICD interventions included shock on ventricular fibrillation (n = 8 patients), shock on ventricular tachycardia (n = 1 patient), and antitachycardia pacing on ventricular tachycardia (n = 1 patient). At survival analysis, history of atrial fibrillation (log-rank test; P = 0.02), conduction disturbances (log-rank test; P < 0.01), S wave in lead I (log-rank test; P = 0.01) and first-degree atrioventricular block (log-rank test; P = 0.04) were significantly associated with the occurrence of late appropriate ICD intervention. At Cox-regression multivariate analysis, S-wave in lead I was the only independent predictor of late appropriate ICD intervention (HR: 9.17; 95%CI: 1.15-73.07; P = 0.03).

Conclusions: The present study indicates that BrS patient receiving a prophylactic ICD may experience late appropriate intervention after GR in a clinically relevant proportion of cases. S-wave in lead I at the time of first clinical evaluation was the only independent predictor of persistent risk of life-threatening arrhythmic events. These findings support the need for GR at the end of service regardless of previous appropriate intervention, mostly in BrS patients with conduction abnormalities.

Keywords: Brugada syndrome; complications; implantable cardioverter-defibrillator; risk stratification; sudden cardiac death.

Figure 1

Baseline ECG of an asymptomatic BrS patient who experienced VF 4 years and 6 months after generator replacement. Note the presence of first-degree AV block and S-wave in lead I as well as spontaneous “coved type” ECG pattern in leads V1 and V2 (A). Intracardiac electrocardiogram obtained from the transvenous ICD remote monitoring showing the onset of VF, triggered by a premature ventricular contraction and its offset by the ICD shock (B).

Figure 2

Kaplan–Meier analysis for survival free from the endpoint according to the presence of history of atrial fibrillation (A) conduction disturbances, (B) S-wave in lead I, (C) and first degree atrio-ventricular block (D).