Screening for Atrial Fibrillation in Native AmeRicans Using iPhone ECG

Atrial fibrillation (AF) is the most common clinically significant arrhythmia and is
associated with increased rates of stroke, heart failure, mortality, hospitalization, and
cognitive decline. Approximately one third of ischemic strokes are attributable to either
previously known or newly detected AF at the time of stroke. Many AF episodes are
asymptomatic and stroke is the first manifestation of AF in at least 25% of AF-related
strokes. Anticoagulation for AF leads to a reduction in stroke to levels similar to matched
individuals without AF. Therefore, identifying AF in an earlier asymptomatic state (i.e.
screening for silent AF), with subsequent initiation of anticoagulation in at-risk
individuals, may decrease the risk of future thromboembolic events. The availability of
inexpensive smartphone-based or handheld ECG devices that rapidly acquire a cardiac rhythm
strip of quality comparable to a traditional 12-lead ECG have markedly enhanced the
feasibility of AF screening. Native Americans have a high prevalence of diabetes and higher
incidence of stroke than whites and blacks. Our central hypothesis is that screening for AF
using a single time point, 30-second iPhone-based ECG recording over 2 weeks will result in
identification of silent AF in a significant number of individuals at risk for stroke
compared to routine care (no screening) and will thus lead to improved outcomes through
initiation of anticoagulation. The aim of this study is to screen for AF in Native Americans
who are seen at the Absentee Shawnee Tribal clinic using a smartphone-based ECG device.
Individuals who are at least 50 years old and have no prior history of AF will be eligible
for enrollment in the study. Eligible participants will receive a 30-second ECG recording
during their visit at the Absentee Shawnee Tribal clinic. The device has an algorithm for
diagnosis of AF, which is 98% sensitive and 97% specific. A cardiologist will overread the
tracings that are diagnosed by AF by the device. Those confirmed to have AF will be referred
to a cardiologist for further evaluation and management. The clinical characteristics of
those who are found to have AF will be compared with those who are not, in order to identify
risk factors for AF. Newly diagnosed AF using this method is expected to be approximately
2.5%. We aim to include a total of 1,500 participants over 12 months. The proposed study will
provide the basis for the design of further intervention studies using mobile technology to
improve the health of Native Americans and other minority populations. In light of the high
prevalence of risk factors for AF in Native Americans and the association of silent AF with
stroke, this novel approach for AF screening has the potential to impact clinical practice
and improve health outcomes among a large number of individuals.