A groundbreaking study has revealed that using iRhythm’s wearable heart monitor can significantly increase the diagnosis rate of atrial fibrillation (AFib) in older adults, though it falls short of reducing stroke-related hospitalizations. The research, known as the GUARD-AF study, aimed to determine if the Zio XT single-lead electrocardiogram (ECG) device could outperform standard care in detecting AFib and subsequently allow for earlier intervention.
Involving nearly 12,000 participants aged 70 and above from across the United States, the study provided compelling new insights. These individuals used the Zio XT device for a two-week period to see if it could identify AFib more effectively than traditional methods. Early detection is crucial, as timely treatment with oral anticoagulants can prevent ischaemic stroke, a severe complication linked to AFib.
Presented at the European Society of Cardiology (ESC) congress, the study’s results were striking. Over an average follow-up period of 15 months, the diagnosis rate for AFib was 5.0% for those using the Zio XT, compared to just 3.3% with standard care. This uptick in diagnoses also corresponded with a rise in anticoagulant therapy (4.2% vs. 2.8%), yet there was no significant increase in hospitalizations due to bleeding complications.
However, not all findings were positive. The trial did not show a decrease in hospitalization rates for strokes, a key objective given AFib’s substantial five-fold increase in stroke risk. According to Professor Renato Lopes of Duke University Medical Center and the study’s lead investigator, the early termination of the trial due to COVID-19 lockdowns played a part in this outcome. The study was originally designed to enroll 52,000 patients, but the early halt compromised its statistical power and, thus, its conclusive potential regarding stroke prevention.
The limitations of the trial were highlighted by Professor Lopes, who suggested that more extensive studies with prolonged follow-up and inclusion of higher-risk participants are necessary to fully understand the Zio XT’s role in stroke prevention. Despite these shortcomings, the study reinforces that AFib is widespread among older adults and can be effectively identified through primary care cardiac monitoring.
AFib is the most prevalent heart rhythm disorder globally, affecting over 40 million people. In the UK, the Zio XT has received endorsement from the National Institute for Health and Care Excellence (NICE) since 2020, as an option for patients who need ECG monitoring for more than 24 hours. It presents an advantageous alternative to conventional Holter monitors, which are bulkier and involve multiple electrodes.
While the GUARD-AF findings align with earlier studies indicating that longer-term AFib screening can raise diagnosis rates, there remains no definitive evidence that such screening can reduce stroke incidences. Professor Lopes emphasized the importance of refining screening parameters, such as target demographics and optimal screening durations, before recommending routine AFib screening.
Intriguingly, the study also revealed that most patients identified with AFib had low-burden paroxysmal AFib, characterized by short, infrequent episodes. These episodes are often missed by pulse checks or shorter ECG monitoring, but their identification could lead to more aggressive treatment of heart disease risk factors, potentially lowering the risk of future heart failure.
For iRhythm, the mixed results present a challenge, though the company remains hopeful. Ongoing trials, such as the AMALFI study in the UK, aim to evaluate the wearable device’s efficacy in NHS settings, with data expected within the next year. Additionally, other studies are examining the Zio XT’s potential in preventing heart failure, reducing cardiovascular hospitalizations, and minimizing healthcare costs.
In summary, while iRhythm’s Zio XT has shown promise in identifying AFib, more extensive research is needed to ascertain its true impact on clinical outcomes, particularly in stroke prevention.