Photoplethysmography promising as AFib screening tool

Continuous at-home monitoring with smart device-based photoplethysmography (PPG) technology could be a viable strategy for AFib screening and early detection, according to a population-level study out of China.

Corresponding author Yundai Chen, MD, PhD, of Chinese PLA General Hospital in Beijing, and colleagues reported their favorable findings in the Journal of the American College of Cardiology this month. The research was rooted in an earlier pilot study from the same team, in which Chen et al. developed and validated a mobile health tech-supported AFib app that wrapped patient support, guideline-based treatment, educational materials and self-care protocols into a single tool.

Incident AFib is a heterogenous condition, the authors said, and since it presents so differently in different people, PPG—a low-cost, noninvasive optical technique that’s used to measure blood volume changes at the skin’s surface—has been increasingly touted as an effective way to screen for the arrhythmia. 

“In the Huawei Heart Study, our aim was to screen for AFib and report the incidence of AFib identified, as well as the proportion of AFib patients being anticoagulated,” Chen and co-authors wrote. “We hypothesized that use of a mobile health PPG technology approach would facilitate AFib screening, and the associated app-based integrated AFib care approach would result in early AFib detection and increased use of oral anticoagulation.”

The team made Huawei PPG technology available to all individuals aged 18 and up in China, and 246,541 people downloaded the PPG screening app. Of that pool, 187,912 used one of two smart devices—either the Huawei Honor Band or Huawei Honor Watch—to monitor their pulse rhythm for at least 14 days.

Participants who recorded pulse data tended to be on the younger side (mean age 35 years) and were 86.7% male. The 424 subjects who received a “suspected AFib” notification from the app were on average older (mean age 54 years) and were urged to take their tenuous diagnosis to a physician, who could then validate AFib with a clinical evaluation, ECG or 24-hour Holter test.

Of the 227 people who effectively followed up with their doctors, 87% were confirmed as having AFib, and 95.1% subsequently entered a program of integrated AFib management using a mobile AFib application. The positive predictive value of PPG signals in the study worked out to 91.6%.

“Our study found that most AFib episodes were found within 14 days, but nearly one-third of AFib episodes were detected on monitoring after two weeks,” Chen and colleagues wrote. “Automatic periodic PPG measurements have the advantage of active measurements in the search for AFib episodes in this study, suggesting that a continuous monitoring approach was better than single-point intermittent monitoring.”

The authors underlined the fact that their integrated app/wearable approach allowed for periodic measurements to be taken automatically every 10 minutes—far more frequently than in the Apple Heart Study, where measurements were taken every two hours until an irregular tachogram was detected, at which point values were recorded every 16 minutes.

Chen et al.’s study also detected less “suspected AFib” than the Apple Heart Study, identifying potential arrhythmias in 0.2% of the general population as opposed to 0.5% in the Apple Heart Study. The authors said the gap could have something to do with the greater prevalence of older patients in the Apple Heart Study, while their population was younger and the prevalence of AFib in the general Chinese population is lower than that of the general American population.

“Continuous home-monitoring with smart device-based PPG technology is a feasible approach for screening and early detection of AFib in a large population,” Chen and co-authors wrote. “This could help inform efforts at screening and detection of AFib, as well as early interventions to reduce stroke and other AFib-related complications.”