High-risk atrioventricular block in Brugada syndrome patients with a history of syncope.

BACKGROUND: Determining the etiology of syncope is challenging in Brugada syndrome (BrS) patients. Implantable cardioverter defibrillator placement is recommended in BrS patients who are presumed to have arrhythmic syncope. However, arrhythmic syncope in BrS patients can occur in the setting of atrioventricular block (AVB), which should be managed by cardiac pacing. The clinical characteristics of BrS patients with high-risk AVB remain unknown. METHODS: This study included 223 BrS patients with a history of syncope from two centers. The clinical characteristics of patients with high-risk AVB (Mobitz type II second-degree AVB, high-degree AVB, or third-degree AVB) were investigated. RESULTS: During the 99 ± 78 months of follow-up, we identified six BrS patients (2.7%) with high-risk AVB. Three of the six patients (50%) with AVB presented with syncope associated with prodromes or specific triggers. Four patients (67%) were found to have paroxysmal third-degree AVB during the initial evaluation for BrS and syncope, while two patients developed third-degree AVB during the follow-up period. The incidence of first-degree AVB was significantly higher in AVB patients than in non-AVB patients (83% vs. 15%; p = .0005). There was no significant difference in the incidence of ventricular fibrillation between AVB and non-AVB patients (AVB [17%], non-AVB [12%]; p = .56). CONCLUSION: High-risk AVB can occur in BrS patients with various clinical presentations. Although rare, the incidence is worth considering, especially in BrS patients with first-degree AVB.

Pravastatin reduces the incidence of cardiac events among patients with myocardial infarction.

We retrospectively compared the incidence of cardiac events in myocardial infarction (MI) patients treated in our departments between 1990 and 1999 with pravastatin or without cholesterol-lowering agents. Our aim was to evaluate the efficacy of pravastatin in the secondary prevention of MI. Cardiac events--defined as fatal or nonfatal recurrent MI, sudden cardiac death, and death from congestive heart failure--occurred in 8 (2.2%) of 356 MI patients treated with pravastatin (17.1 cases/1.000 person x year) and in 39 (5.6%) of 700 MI patients not treated with cholesterol-lowering agents (54.3 cases/1000 person x year), which represented a significant decline among those taking pravastatin (P < 0.05, odds ratio: 0.39, 95% (CI: 0.18-0.84). Likewise, total mortality was significantly lower among patients treated with pravastatin (18 cases, 5.1%; 38.4 cases/1,000 person x year vs 77 cases, 11.0%; 107.2 cases/1,000 person x year, P < 0.01, odds ratio: 0.43, 95% CI: 0.25-0.73). Subgroup analysis revealed a significantly lower incidence or cardiac events in the pravastatin group for 6 of the items among 53 patient characteristics, and was lower but not significant for 45 items and was greater but not significant only for 2 items. Furthermore, multivariate analysis confirmed pravastatin to be a useful factor for preventing the occurrence of cardiac events in MI patients (P < 0.05, odds ratio: (0.44, 95% CI: 0.20-0.95), and Kaplan-Meier curves also showed pravastatin to significantly reduce the incidence of both cardiac events and total mortality. These findings are consistent with those previously reported by several large-scale clinical trials carried out in Western countries, and demonstrate that pravastatin is useful for secondary prevention of MI in Japanese patients.