Risk of atrial fibrillation according to electrocardiographic risk factors: a nationwide cohort study of 1.5 million patients

Atrial fibrillation (AF) is associated with an increased risk of stroke, yet no evidence exists on the collective effect of electrocardiogram (ECG) risk factors in early detection of AF. We aimed to evaluate the risk of new-onset AF and stroke according to specific ECG risk factors to identify patients at high risk of developing AF.

We included patients who had an ECG performed and grouped them according to how many of the following ECG risk factors they presented with: Elevated heart rate at rest, prolonged PR-interval, biphasic P-waves, abnormal P-terminal force in V1, and prolonged P-wave duration. Among 1 434 491 included patients, 632 628 had none of the five ECG risk factors and 802 163 had at least one ECG risk factor on their ECG. The 5-year cumulative incidence of AF and stroke was lowest among patients with no ECG changes and exceeded 8% and 7%, respectively among patients with all five ECG risk factors [AF: 8.3%, 95% confidence interval (CI): 5.7–11.0%, stroke: 7.3%, 95% CI: 4.7–9.9%]. Patients with all five ECG risk factors had a two-fold increased risk of AF [hazard ratio (HR): 2.57, 95% CI: 1.85–3.57] and of stroke (HR: 2.11, 95% CI: 1.47–3.01) compared to patients with none.

The selected ECG risk factors were commonly observed. The 5-year incidence of AF and stroke was low among patients with no ECG risk factors, yet increased in a dose–response-like manner according to the number of ECG risk factors. Scoring patients according to simple ECG risk factors effectively identified patients at high risk of AF and stroke.