Heart Monitor Screening for Atrial Fibrillation

Study Questions:

Does a strategy of twice-weekly ambulatory electrocardiogram (iECG) monitoring result in greater diagnostic yield of atrial fibrillation (AF) in patients ≥65 years of age with a CHA2DS2-VASc score ≥2?

Methods:

Patients were randomized to an AliveCor Kardia monitor attached to a WiFi-enabled iPod to obtain ECGs (iECGs) or routine care. iECG participants acquired iECGs twice weekly over 12 months. Time to diagnosis of AF was the primary outcome measure. The overall cost of the devices, ECG interpretation, and patient management were captured and used to generate the cost per AF diagnosis in iECG patients.

Results:

There were 1,001 patients (500 iECG, 501 routine care). They were on average 73 years of age; 534 were female. Mean CHA2DS2-VASc score was 3.0. Nineteen patients in the iECG group were diagnosed with AF versus 5 in the routine care arm (hazard ratio, 3.9; 95% confidence interval, 1.4–10.4; p = 0.007) at a cost of $10,780 (£8255) per AF diagnosis. There was a similar number of stroke/transient ischemic attack/systemic embolic events in both arms (6 vs. 10, iECG vs. routine care; hazard ratio, 0.61; 95% confidence interval, 0.22–1.69; p = 0.34).

Conclusions:

Screening with a twice-weekly single-lead iECG with remote interpretation in ambulatory patients ≥65 years of age at increased risk of stroke is significantly more likely to identify incident AF than routine care over a 12-month period.

Perspective:

Up to one third of strokes of undetermined origin may be caused by previously undetected and untreated AF. Prior studies utilizing pacemakers and implantable cardioverter-defibrillators showed increased risk of stroke in patients with so-called atrial high rate episodes, most of which represent atrial fibrillation or atrial flutter. One study showed that atrial high rate episodes as short as 5 minutes in MOST or 6 minutes in ASSERT studies were associated with an increased risk of stroke, although there did not appear to be a temporal association between AF and embolic events. It is still unclear whether anticoagulation, triggered by the detection of asymptomatic AF, reduces the risk of stroke in this population. While the present study was underpowered for hard clinical endpoints, the incidence of embolic events did not differ significantly between patients randomized to iECG or routine care. There are two randomized trials underway, which in a few years will hopefully provide some guidance: ARTESiA (Apixaban for the Reduction of Thrombo-Embolism in Patients With Device-Detected Sub-Clinical Atrial Fibrillation) and NOAH (Non-Vitamin K Antagonist Oral Anticoagulants in Patients With Atrial High Rate Episodes).


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