A recent article summarizes current knowledge and discusses challenges related to atrial fibrillation and heart failure.
Pharmacists looking for a concise description of studies concerning the relationship between atrial fibrillation (AF) and heart failure (HF) should read an article published online on January 17, 2014, in the American Journal of Cardiology
. In slightly more than a page, the authors of “Atrial Fibrillation and Heart Failure: A Bad Combination”
summarize current knowledge and discuss challenges related to these comorbidities.
AF and HF share several risk factors. Hypertension, increasing age, valvular heart disease, previous ischemic cardiac event, and diabetes mellitus all increase the likelihood that 1 or both conditions will develop. In addition, AF and HF each increases stroke and death risk on their own. When they occur together, AF and HF create a prothrombotic state that worsens stroke morbidity and mortality compared with outcomes related to either condition alone.
Among the surprising findings these authors review is that although moderate to severe cardiac dysfunction in HF patients clearly predisposes them to thromboembolism, a significant number of patients who have been coded as having “heart failure” in databases do not have actual HF but have been so coded due to diagnostician or medical coder error. This complicates study in clinical settings.
The authors also note that study findings vary concerning HF’s association with stroke risk. Some studies indicate that HF increases risk, while others indicate that it does not. The authors call attention to differing definitions of HF with reduced ejection fraction used in studies. Studies that include significant numbers of patients with mild or low normal left ventricular systolic function could skew results in such a manner that reduced stroke or thromboembolic event rates are more likely to be reported.
Other factors that affect study results include failure to consider, record, or monitor a broad range of risk factors associated with AF or HF, or using inconsistent definitions.
A last and critical issue covered in the article is the need to provide patients with effective treatment for stroke prevention. Many AF and HF patients, despite elevated stroke risk, are not taking oral anticoagulants. This is an area where improvement is sorely needed; clinicians need to use anticoagulation more aggressively when it is indicated.
Ms. Wick is a visiting professor at the University of Connecticut School of Pharmacy and a freelance writer from Virginia.