The atrial fibrillation paradox -connecting hypertension to atrial disease and stroke.

A “double paradox” exists in the understanding of racial differences in the association between traditional cardiovascular (CV) risk factors, the incidence and prevalence atrial fibrillation (AF), and the increased incidence of ischemic stroke. Simply stated, Black persons have an increased number of CV risk factors yet less AF. Despite lower incidence of AF, Black individuals have higher rates of stroke and systemic embolism. This important public health challenge is notable, given that, despite a significant decline in overall stroke mortality rates since the 1950s, age-adjusted stroke death rates have remained higher in Black versus White individuals through 2008.[2] The purpose of this review is to examine the risk of ischemic stroke in Black persons and provide a summary of options to improve the recognition of individual risk and reinforce preventive care. Consider the following concepts: • Black individuals have more traditional CV risk factors and higher rates of ischemic stroke, than their non-Hispanic White counterparts, yet a lower incidence and prevalence of AF. • The difference in the incidence of AF does not fully explain the differences in stroke risk • The explanation for these differences is likely complex and leads to the following questions. ○ Should researchers and clinicians reassess the way atrial disease and embolic risk are defined in specific populations? ○ Do traditional risk factors for AF account for increased stroke risk in select patient populations which also needs to be re-evaluated in the context of stroke reduction. As with prior work[1,17,18,19,21] which has addressed the “AF Paradox” this review supports the concept of atrial disease - including atrial fibrillation - as a continuum. There also appears to be a risk of stroke associated with this continuum in the absence of a diagnosis of AF.[1,18,21] These factors alone do not account for the differences in overall stroke rates in Black persons. In addition to a revision on the views of atrial disease, there should be a renewed emphasis early and aggressive blood pressure control – as well as other risk factor management – in Black individuals to affect the differences in stroke rates. The objective of this review is to re-examine the specific role of hypertension in atrial disease and perceptions on stroke risk, AF and possible differences between Black and White individuals.