Telephone training to improve ECG quality in remote screening for atrial fibrillation.

Objective: Self-recorded, single-lead ECGs are increasingly used to diagnose arrhythmias. However, they can be of variable quality, affecting the reliability of interpretation. In this analysis of ECGs collected in atrial fibrillation screening studies, our aims were to: (i) determine the quality of ECGs when recorded unsupervised; and (ii) investigate whether telephone training improved ECG quality. Approach: Data was obtained from the Screening for Atrial Fibrillation with ECG to Reduce stroke (SAFER) programme, where participants recorded four single-lead ECG traces per day for three weeks using a handheld device. ECG quality was assessed by an automated algorithm, and participants who recorded >25% poor-quality ECGs from days 4-10 of screening were identified for training to improve ECG recording technique. Training was delivered when research team capacity permitted. Main results: 13,741 participants recorded 1,127,264 ECGs, of which 41,288 (3.7%) were poor-quality. Most participants (51.5%) didn't record any poor-quality ECGs. 1,088 (7.9%) participants met the threshold for training. Of these, 165 participants received training and 923 didn't. The median proportion of poor-quality ECGs per participant on days 1-3 was 41.7 (27.3-50.0) % for those who received training and 33.3 (25.0-45.5) % for those who didn't. On days 11-21, the median proportions of poor-quality ECGs per participant were significantly lower (p<0.001) for those who received training, 17.8 (5.0-31.6) %, and those who didn't, 14.0 (4.8-30.2) %. Comparing these groups, the mean (95% confidence interval) reduction in proportion of poor-quality ECGs from days 1-3 to days 11-21 was 20.2 (16.8-23.5) % in those who received training and 16.0 (14.7-17.3) % in those who didn't (p=0.396). Significance: Most participants achieved adequate quality ECGs. For those that didn't, ECG quality improved over time regardless of whether they received telephone training. Telephone training may therefore not be required to achieve improvements in ECG quality during screening. .