A screening model using intermittent versus continuous ECG monitoring can identify up to two thirds of people with asymptomatic atrial fibrillation (AF), research shows.

The US study found two 30 second ECG snapshots per day obtained with a patch monitor over a 14-day period could detect about half (52%) of affected individuals.

Increasing to three or four ECG snapshots per day could increase the detection rate to 61% and 66% respectively, while a single measurement per day would detect only 35% of AF.

The study, published in EP Europace and using the iRhythm Zio XT single-lead ECG monitoring skin adhesive patch, also found the probability of detecting an AF episode with intermittent monitoring increases as the AF burden for the individual increases.

“Using two ECG snapshots per day over a 14-day period, for the 52% of individuals detected, the median burden was 4.0%, IQR: 2.49–27.2% (median values over all the screening repetitions), while the median individual average duration of an AF episode was 233 min, IQR: 49–914,” the study authors wrote.

“For the remaining 48% whose AF was not detected by twice-daily screening, median burden was much lower at 0.68%, IQR: 0.18–1.58% (P < 0.001), while the duration of the average individual episode of AF was 8 min, IQR: 3–70 (P < 0.001).”

Professor Ben Freedman, an Australian co-author on the paper, told the limbic Australia has access to some patch recorders but more were coming.

“The other kid on the block is the wearable technology which can be done for longer but you get a better recording from the patch recording,” he said.

“The thing that we are learning is that the prognosis of people with infrequent short episodes is not the same who have prolonged episodes or continuous atrial fibrillation. There is not the high stroke risk.”

“So you have a trade off between intensity of monitoring and the yield of AF and the risk of stroke. If you look more, you will find more but the more you find is of a lower risk. We don’t know the cut-off point of burden that really increases risk.”

Professor Freedman, Group Leader of the Heart Rhythm And Stroke Group at the Heart Research Institute in Sydney, said a number of pivotal RCTs were underway.

“If you want to do more systematic screening or you want to do more intensive screening then you have to show that you are doing more good than harm and look at the prognosis of these people that you pick up,” he said.

Studies such as the Swedish STROKESTOP trial should report in next six months and the Danish LOOP study within 12 months, he said.