Simplified electrocardiogram sampling maintains high diagnostic capability for atrial fibrillation: implications for opportunistic atrial fibrillation screening in primary care

Abstract

Aims: Atrial fibrillation (AF) is a major cause of morbidity, mortality, and health resource consumption. However, as many patients with chronic AF are asymptomatic, rapid, accurate opportunistic screening is needed in primary care to detect AF. Conventional electrocardiogram (ECG) technology is too clumsy and time consuming for mass opportunistic screening, thus technology that allows easy, rapid, yet accurate AF screening is required. To address this requirement a prototype hand-held electrode assembly was developed. We hypothesized that a 6-lead frontal-plane ECG acquired from this apparatus in a seated, clothed patient would be as accurate at detecting AF as conventional 12-lead ECG in the undressed, supine patient (the 'gold standard').

Methods and results: Electrocardiograms were obtained from 78 patients with AF and 79 with sinus rhythm (SR). All had a conventional 12-lead ECG, a 6-lead ECG from conventionally positioned limb electrodes, a supine 6-lead recording using the prototype recorder placed on the lower thorax/upper abdomen, and a 6-lead prototype recording in the seated patient, the latter with loosened clothing only. Electrocardiograms were randomly and blindly assessed by two cardiologists for (i) diagnosis of AF vs. SR and (ii) tracing quality (subjectively assessed as good, adequate, or bad). Compared with conventional 12-lead ECG recordings, all 'new' recording methods performed satisfactorily with sensitivities ≥90% (90-99%), specificities ≥94% (94-100%), positive predictive values ≥94% (94-100%), negative predictive values ≥90% (90-99%), and accuracies ≥93% (93-99%). Tracing quality was higher in conventional 12-lead recordings (71 and 80% were assessed as good by the two observers) compared with conventional 6-lead (57 and 59%), supine prototype (41 and 31%), and sitting prototype (39 and 19%).

Conclusions: Despite inferior electrocardiographic quality a 6-lead frontal plane ECG acquired by a simple prototype hand-held electrode assembly allowed reliable differentiation of AF from SR compared with standard 12-lead ECG.