Smartphone Versus Holter Monitoring for Poststroke Atrial Fibrillation Detection

MONTREAL—In patients hospitalized for a recent acute ischemic stroke or transient ischemic attack (TIA), a smartphone-based method identified three times more patients with atrial fibrillation than did 24-hour Holter monitoring after discharge, according to a study presented at the 11th World Stroke Congress.

This high level of atrial fibrillation detection suggests that this relatively cheap and noninvasive device is a good complement to conventional monitoring by a 24-hour Holter recording or an implanted loop recorder in patients with recent stroke. The device may thus satisfy the requirements of current guidelines from the world’s cardiology societies.

In-Hospital and Postdischarge Monitoring

In the study, 294 of 1,079 patients with acute ischemic stroke or TIA underwent serial, 30-second monitoring with the AliveCor device while hospitalized. The device was designed for smartphone-enabled ECG measurement. After discharge, the same patients underwent Holter monitoring. The latter technique identified eight patients (3%) with atrial fibrillation, compared with 25 patients (9%) who were identified using the AliveCor device, said Bernard Yan, MD, a consultant neurologist and endovascular neurointerventionist in the Comprehensive Stroke Center of the Royal Melbourne Hospital. Seven of the eight patients identified with atrial fibrillation by Holter monitoring were also found to have atrial fibrillation by the AliveCor device.

Bernard Yan, MD

Dr. Yan attributed the higher in-hospital detection rate for atrial fibrillation to the timing of screening, which occurred within days of the stroke or TIA, rather than after the patient had left the hospital. “The difference may be because we monitored patients [with the AliveCor device] much earlier, during their hot period right after their stroke.”

Practice Does Not Match Recommendations

The trial, which was called SPOT-AF, was conducted at several centers in Australia, China, and Hong Kong. All patients underwent AliveCor monitoring during their stay in the hospital, which lasted for a median of four days. Patients performed a 30-second heart rhythm check every time a nurse saw them for a routine vital-sign examination, which usually was three or four times per day. The current analysis focused on the 294 patients (27% of the 1,079 patients) who also underwent 24-hour Holter monitoring following hospital discharge when ordered by their personal physician.

This 27% rate of postdischarge Holter monitoring was consistent with that of a 2016 review of more than 17,000 patients with stroke or TIA in Canada. That study found that 31% of participants underwent 24-hour Holter monitoring for atrial fibrillation during the 30 days following their index event. Guidelines, however, call for atrial fibrillation screening in all patients with recent ischemic stroke and TIA.

Although screening for atrial fibrillation with a smartphone-based device is inexpensive and easy, Dr. Yan did not suggest that this approach could replace a Holter monitor or an implanted loop recorder, which is what current guidelines recommend. “To change the guidelines, we need a different study that compares these approaches head to head.”

SPOT-AF received partial funding from Boehringer Ingelheim. Dr. Yan has spoken on behalf of Bayer, Boehringer Ingelheim, Pfizer, and Stryker.