Optimizing Treatment to Reduce Mortality and Improve Clinical Outcomes

Strokes that occur after the onset of atrial fibrillation (AF) have a worse prognosis than strokes that do not occur in the setting of AF. Recent studies suggest that strokes that occur within several months prior to an AF diagnosis may be related to underlying, silent AF. At the AHA Scientific Sessions, collaborating researchers from the University of Pennsylvania, Philadelphia, and the University of Washington, Seattle, presented their evaluation of the differences in the risk of all-cause death between patients that develop stroke in the 6 months before, compared with any time after, the diagnosis of AF.

The presenters utilized the University of Pennsylvania AF Free study to create an inception cohort of patients with incident stroke and AF. They assessed electrocardiograms, clinical records, and administrative data within the health system over a 5-year period to identify individuals that had a first diagnosis of stroke or AF. Cox proportional hazards models evaluated associations between stroke subtypes and death.

Researchers identified 3616 individuals that developed stroke (323 had stroke after AF diagnosis, 292 patients had stroke within the 6 months preceding AF diagnosis, and 2795 patients had stroke without an AF diagnosis). Of these patients, there were 319 all-cause mortality events over a median 4.6 years follow-up. The overall mortality rate was highest in patients that had a stroke within 6 months prior to AF and was almost 2-fold higher than for those that had a stroke after an AF diagnosis. After multivariable adjustment, patients with an AF-related stroke that occurred within 6 months prior to the diagnosis of AF had a significantly higher risk of death than those with stroke that occurred after an AF diagnosis or without an AF diagnosis. The researchers concluded that the higher risk of all-cause death associated with stroke occurring prior to an AF diagnosis is not explained by the presence of other comorbid conditions. 

In another presentation, an international team of researchers from Brazil and the United States shared the results of their study of the effects of class III antiarrhythmic drugs on the frequency of implantable cardioverter defibrillator (ICD) therapies, as well as hospitalization rates and mortality, in patients with heart failure. ICDs can reduce ventricular arrhythmias (VA) and prolong survival in patients with heart failure. However, ICD therapies are associated with significant pain, psychological distress, and increased risk for hospitalization and mortality. Antiarrhythmic drugs are commonly used to reduce frequency of VA in patients and, thus, can potentially reduce the need for  ICD treatment.

The researchers conducted a literature search to identify prospective randomized controlled trials comparing class III antiarrhythmics to placebo on a background of standard medical therapy in patients with an ICD and prior history of sustained VA (spontaneous, treated, or induced) and/or sudden cardiac death. After reviewing 2931 articles, seven trials that studied amiodarone, sotalol, azimilide, or celivarone were included in the evaluation. A total of 2117 patients (male, 87%; mean age, 63.8 years) were analyzed. Of these patients, 50.6% had at least one appropriate ICD therapy delivered, and 4.5% died during the follow-up period. Antiarrhythmic drug usage significantly reduced the number of patients receiving ICD therapy by 55%. There was no significant difference in mortality between patients treated with antiarrhythmics and those treated with placebo. Only 2 of the 7 trials reported number of hospitalizations; thus, the sample size was insufficient for analysis.

The researchers concluded that class III antiarrhythmics significantly reduced the use of ICD therapy in patients with VA without increasing mortality and, therefore, may be used to improve clinical outcomes in patients with heart failure.