Mexiletine as an adjunctive therapy to amiodarone reduces the frequency of ventricular tachyarrhythmia events in patients with an implantable defibrillator.

The most effective pharmacological management of frequent ventricular tachyarrhythmia events in patients with an implantable defibrillator who failed or did not tolerate amiodarone is unknown. The aim of this retrospective cohort study was to assess the efficacy and tolerability of mexiletine in such patients. The patients served as self-controls. The number of treated ventricular tachyarrhythmia episodes (primary outcome); mortality, shocks from the defibrillator, and electrical storm events (secondary outcomes) during mexiletine therapy was compared with a matched duration of observation just before initiating mexiletine in 29 patients who were treated with a median dose of 300 mg/d of mexiletine and were followed for a median of 12 months. None of the patients had to stop mexiletine due to side effect. There was a significant reduction in the incidence of ventricular tachycardia/fibrillation episodes (median 2 vs. 12 events, P = 0.001) and shocks (median 0 vs. 2 events, P = 0.003) in the first 3 months of treatment, but long-term efficacy was only observed among patients who continued amiodarone therapy. In conclusion, mexiletine, when added to amiodarone in case of amiodarone inefficacy, reduces ventricular tachycardia/fibrillation events and appropriate therapies in patients with an implantable cardioverter defibrillator. A randomized trial should validate the efficacy and safety of mexiletine as an adjunctive therapy to amiodarone.

Management and outcome of acute coronary syndrome patients in relation to prior history of atrial fibrillation.

BACKGROUND: The prognostic impact of atrial fibrillation (AF) in the setting of acute coronary syndrome (ACS) is controversial. Furthermore, there are limited real-world data on the management of ACS patients with history of AF. METHODS: The Global Registry of Acute Coronary Events (GRACE/GRACE2) and Canadian Registry of Acute Coronary Events (CANRACE) enrolled 14,285 patients across Canada between 1999 and 2008. Patients were stratified by the presence of history of AF. We compared clinical characteristics, medical therapies, cardiac procedures, and clinical outcomes between the 2 groups. RESULTS: Overall, 1333 of the enrolled patients (9.3%) had history of AF, of whom 51.5% presented with non-ST-segment elevation myocardial infarction, 29.5% with unstable angina, and 19.1% with ST-segment elevation myocardial infarction. Compared with the group without, patients with a history of AF less frequently received evidence-based antiplatelet and antithrombin therapies, left ventricle ejection fraction assessment, and coronary angiography (all P < 0.001); they also had higher unadjusted rates of in-hospital death, myocardial (re)infarction, and heart failure. However, in multivariable analysis, history of AF was not found to be independently associated with in-hospital mortality (adjusted odds ratio [OR] = 1.12; 95% confidence interval (CI), 0.73-1.73; P = 0.61) or death and/or myocardial reinfarction (adjusted OR = 1.15; 95% CI, 0.87-1.5; P = 0.34). CONCLUSIONS: History of AF is common among ACS patients. They received less evidence-based medical and invasive therapies than ACS patients without history of AF. History of AF is a negative independent predictor of in-hospital coronary angiography but was not found to be independently associated with adverse outcomes.