A smartphone-based electrocardiogram (ECG) screening accurately detected previously unknown atrial fibrillation (AF) in American Indians, and more than half who were diagnosed were younger than the recommended screening age of 65, according to new research published in the Journal of the American Heart Association.
American Indians are more at risk for AF than people in other racial and ethnic groups in the USA. As a population, American Indians also have substantially higher rates of obesity, diabetes and high blood pressure—all risk factors for AF.
“We know the risk of AF is high in people who are from racial and ethnic groups, especially among American Indians, so we wanted to see if we could identify silent AF,” said lead study author Stavros Stavrakis, cardiologist at the Heart Rhythm Institute of the University of Oklahoma Health Sciences Center and associate professor of medicine at the University of Oklahoma College of Medicine in Oklahoma City, USA. “Systemic screening among American Indians has never been done before, and the true rate of AF in this population is unknown.”
Researchers enrolled 1,019 American Indians, ages 50 and older, 63% female, who received care at one of four tribal primary care clinics in the Absentee Shawnee Tribal Health System in Oklahoma between January 2019 to June 2020, to examine the feasibility and effectiveness of atrial fibrillation screening using a mobile, smart device.
Participants underwent a 30-second, single-lead ECG using the mobile device paired with a tablet or smartphone at the clinic. Researchers compared the ECG results of the screened participants to the results of a control group: 1,267 American Indian adults, ages 50 and older, who received care at the Absentee Shawnee Tribal System clinics during the same time period but did not receive the mobile-based ECG screening.
Their analysis comparing the two patient groups found that of the 1,019 participants who received the mobile-based ECG screening, AF was found in 15 patients (1.5%). In contrast, only four of the 1,267 (0.3%) patients in the control group (standard care, based on clinical symptoms alone) were diagnosed with AF.
About half of those diagnosed with atrial fibrillation by mobile-based ECG (eight of 15 patients) were younger than 65. Patients diagnosed with AF by mobile device were slightly older than those who were not screened with a smart device and did not have the condition. Of the 15 patients diagnosed with AF, 14 had a high risk of stroke, as measured by the CHADS2-VASc score and met the criteria for initiation of blood thinning medication according to current guidelines.
“Our study shows that we have a very simple and accurate method to screen and diagnose AF that is easy to implement at tribal clinics,” Stavrakis said. “This widely-available, low-cost approach has real potential to improve health outcomes among American Indians.
“In a targeted, high-risk population such as American Indians, our results showed screening at a younger age found many cases of atrial fibrillation that would have been missed following current age recommendations. We have the potential to improve outcomes in this population by initiating early treatment.”
A major limitation of the study is that it was not a randomised intervention. The next step will be to do a randomised, controlled trial to get more robust data, Stavrakis said.