Am J Cardiol：心脏复律者需密切监测药物所致心律失常

　　美国一项研究表明，接受化学心脏复律（CCV）的持续性房颤患者需要对药物所致的心律失常进行更为密切的监测。论文于5月24日在线发表于《美国心脏病学杂志》（Am J Cardiol）。

　　多非利特为为III类抗心律失常药物，被批准用于持续性房颤患者的窦性心律维持。此项研究共纳入99例心脏复律前接受负荷量多非利特治疗的持续性房颤患者，并评估了CCV是否预示致心律失常风险升高。

　　结果显示，分别有46和53例接受CCV和电复律（ECV）治疗。在索引住院期间，CCV组因QT延长或扭转性室速（TdP）所致的多非利特停药率高于ECV组（P=0.001）。需停药的CCV组患者均在单剂多非利特治疗后实现复律。3例Tdp患者均在CCV组。在首剂多非利特应用后复律的CCV组患者中，71%出现显著QT延长，需调整药物剂量或停药。

　　在为期2年的随访期间，两组出院患者的房颤复发率和停药率基本相似。在因启用多非利特而住院的患者中，近50%接受CCV，并且其与病理性QT延长和TdP发生率升高具有相关性。

Frequency of Toxicity With Chemical Conversion of Atrial Fibrillation With Dofetilide
Abstract
Dofetilide is a class III antiarrhythmic agent approved for the maintenance of sinus rhythm in patients with persistent atrial fibrillation (AF). The goal of this study was to determine if chemical cardioversion (CCV) suggests a greater sensitivity to dofetilide and, therefore, portends a higher risk of proarrhythmia. We analyzed 99 consecutive patients with persistent AF who were loaded on dofetilide before cardioversion. CCV occurred after 2 ± 1.5 doses of dofetilide in 46 patients whereas electrical cardioversion (ECV) was required in the remaining 53 patients after 4.7 ± 1.3 doses. During index hospitalization, there were higher rates of dofetilide discontinuation because of QT prolongation or torsades de pointes (TdP) in the CCV group compared with the ECV group (24% vs 2%, p = 0.001). All patients with CCV requiring drug discontinuation converted after a single dose of dofetilide. Additionally, all 3 patients with TdP were in the CCV group. Furthermore, 15 of the 21 patients with CCV (71%) who converted after the first dose of dofetilide developed significant QT prolongation, requiring dose adjustment or discontinuation of drug. Among patients discharged on drug, AF recurrence and drug discontinuation rates were similar between groups at 2-year follow-up. In patients hospitalized for initiation of dofetilide, CCV occurs in almost 50% and is associated with higher rates of pathologic QT prolongation and TdP compared with those who require ECV. Once discharged on dofetilide, safety and efficacy is similar in both groups. In conclusion, patients with CCV may require closer monitoring for proarrhythmia.