For eligible patients from primary care clinics randomly selected for the Atrial Fibrillation Spot-Check arm, practice medical assistants will screen assenting patients for undiagnosed AF during regularly scheduled office visits using a single-lead handheld electrocardiogram (ECG). Single-lead handheld electrocardiogram readings detecting AF will be confirmed during the same office visit with a standard 12-lead ECG at the discretion of the primary care physician. If AF is detected, the patient's PCP will be able to address the condition with them during the clinic visit and initiate appropriate follow-up to manage the AF.

For eligible patients from primary care clinics randomly selected for the Usual Care arm, they will receive standard care during outpatient visits without change.

Screening for atrial fibrillation during outpatient primary care office visits among patients 65 years and older

The numerator of the outcome is the number of eligible patients with newly diagnosed AF during the study period. The eligible study population comprising the denominator will be assessed in two ways: (1) the whole population, defined as all patients aged 65 years and older presenting for an outpatient clinic appointment with a participating physician, nurse practitioner, or physician assistant at a study clinic during the enrollment period, and (2) the whole population excluding patients with an AF diagnosis prior to outcome assessment (prevalent AF).

The numerator of the outcome will be the number of eligible patients with newly diagnosed AF associated with a primary care visit. Similar to the primary outcome, the denominator will be assessed in two ways: (1) the whole population, and (2) the whole population excluding prevalent AF.