A secondary analysis of the Apple Heart Study looking at outcomes related to electrocardiogram (ECG) patch monitoring after an irregular pulse notification from an Apple Watch app, "provides a foundation for large-scale pragmatic studies in which outcomes or adherence can be reliably assessed with user-owned devices," said researchers. Finding from the analysis were presented at AHA 2019 and published in the New England Journal of Medicine (NEJM).

The analysis by Marco V. Perez, MD; John S. Rumsfeld, MD, PhD, FACC, et al. looked at 450 of the 2,161 participants enrolled in the Apple Heart Study who had received an irregular pulse notification from the Apple Watch. This smaller group participated in a telemedicine visit following the notification and then completed wearing an ECG patch monitor for an average of 6.3 days.

Of these participants, AFib was observed in 34 percent of patients overall and in 35 percent of those 65 years of age or older. Among participants who were notified of an irregular pulse, the positive predictive value was 0.84 for observing AFib on the ECG simultaneously with a subsequent irregular pulse notification and 0.71 for observing AFib on the ECG simultaneously with a subsequent irregular tachogram, researcher said.

In addition to AFib, ECG patch monitoring also identified several arrhythmias that may require further medical attention. Of the 297 participants without AFib, researchers noted that 25 percent had a premature atrial contraction (PAC) burden between 1-15 percent; 1.3 percent had a PAC burden ≥ 15 percent; and 3.7 percent had an episode of NSVT ≥ 8 beats. An additional five patients had episodes of high-grade AV block associated with transient sinus slowing lasting less than 4 seconds or ≥ 15 percent premature ventricular contractions. No patient had Mobitz II or complete heart block and there were no reports of serious app-related adverse events, researchers said.

In a related NEJM editorial, Edward W. Campion, MD, and John A. Jarcho, MD, FACC, write: "After taking over media, social communication, and the consumer economy, the forces of digital innovation are moving into the worlds of medical practice and medical research. Both the power and the limitations of digital innovation in medicine are evident in [the] report by Perez and colleagues."

Campion and Jarcho highlight several ways the Apple Heart Study data can be valuable, including challenging clinicians to "reassess the relation of AFib to stroke." However, they also caution about risks and challenges, ranging from "obtaining long-term patient commitment and compliance" to the "need to protect the interests of patients against the use of technology that ignores the greater good."

Clinical Topics: Arrhythmias and Clinical EP, Sports and Exercise Cardiology, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: AHA19, AHA Annual Scientific Sessions, Sports, Atrial Fibrillation

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