Atrial Fibrillation Not So Benign For Women

Atrial fibrillation (AF) occurs when the heart loses it's pacemaker or symphony conductor, so to speak.  This loss manifests itself in a widely varying heart rate, often described as irregularly irregular.  The heart speeds up & slows down of its own accord w/o any rhyme or reason.  Unless one's heart rate becomes unreasonably fast which is then noticeable as racing beats, palpitations, or fluttering in the chest, or becomes unreasonably slow which is then noticeable as fatigue and/or (pre)syncope, it can often escape notice for quite some time.

AF is also associated with a not insignificant loss of cardiac efficiency, known as ejection fraction.  However, up until this week, what's most worrisome about AF is that it dramatically increases one's risk for stroke.  Luckily, this risk can be mitigated by proper anticoagulation, typically w/oral warfarin.  In fact, there are several online calculators available to determine both stroke risk from AF (CHADS2 & CHA2DS2VASc) and bleeding risk from warfarin (HAS-BLED).

So why the fuss & preamble?  In another analysis of the Women's Health Initiative published this week in JAMA, after following 34,722 predominantly Caucasian women, average age 53 years old, all free of AF & cardiovascular disease at baseline for median of 15+ years, the authors concluded that new onset AF was associated with an increase risk of all-cause mortality, cardiovascular mortality & non-cardiovascular mortality, at least double that of those without AF.

While the overall risk of developing AF is low, the fact remains that upon diagnosis, one's mortality increases substantially.  While this study makes no conclusions as to cause & effect and while there is no proof of any ability to modify mortality once AF is diagnosed, there is no reason not to aggressively prevent stroke & cardiovascular events from occurring.