Future of wearable trackers in health care, with focus on atrial fibrillation detection

Atrial fibrillation, a common heart rhythm anomaly, often emerges after 65, affecting one in three individuals throughout their lives.

The risk of stroke escalates fivefold with atrial fibrillation, yet judicious use of blood thinners can slash this risk by up to two-thirds.

Interestingly, atrial fibrillation can often remain silent, silently influencing the heart's rhythm without symptoms. In certain cases, it manifests briefly and fades by the time medical attention is sought, making detection elusive.

Approximately one out of every four strokes can be traced back to atrial fibrillation, a revelation often uncovered after the fact.

The ability to identify covert atrial fibrillation offers a potent opportunity for stroke prevention.

Enter modern technology. The Apple Heart Study unveiled a noteworthy correlation between irregular heartbeats detected by their watch and subsequent atrial fibrillation discerned via an ECG patch. Similar findings have emerged from other studies utilizing wearables and home ECG monitors.

A novel term, "subclinical atrial fibrillation," is coined to characterize atrial fibrillation incidentally spotted by smartwatches, implanted cardiac pacemakers, or other wearable cardiac devices. Astonishingly, the ASSERT study estimates "subclinical atrial fibrillation" to be eight times more prevalent than its "clinical atrial fibrillation" counterpart.

Amidst the landscape of "subclinical atrial fibrillation," certain uncertainties linger. Stroke risk appears relatively lower (2.5-fold increased risk vs. the 5-fold with traditionally detected atrial fibrillation), spurring discussions about optimal treatment duration. For instance, fleeting episodes of "atrial fibrillation" lasting mere seconds are occasionally unearthed during routine pacemaker checks, yet solid data to warrant treatment for such brevities is lacking. The TRENDS study suggests that atrial fibrillation should exceed 5.5 hours per day to warrant significant concern.

In a nutshell, who stands to gain the most from wearable devices for irregular heartbeat detection?

In our view:

- Individuals aged 65 and above,

- Those at heightened stroke risk (with a combination of risk factors like diabetes, high blood pressure, congestive heart failure, or prior heart attacks),

- Individuals with a history of stroke where initial investigations failed to unveil atrial fibrillation.

Additionally, those who sporadically experience palpitations or rapid heartbeats lasting longer than a few minutes, but occurring less frequently than once a month, might find value in these devices. Regular, medical-grade external wearable ECGs might not be practical for extended use beyond a month.

References: TRENDS, ASSET, Apple Heart Study, e-Brave AF trials.