Detection of atrial fibrillation in primary care with radial pulse palpation, electronic blood pressure measurement and handheld single-lead electrocardiography: a diagnostic accuracy study

Abstract

Objective: To determine the diagnostic accuracy of three tests-radial pulse palpation, an electronic blood pressure monitor and a handheld single-lead ECG device-for opportunistic screening for unknown atrial fibrillation (AF).

Design: We performed a diagnostic accuracy study in the intention-to-screen arm of a cluster randomised controlled trial aimed at opportunistic screening for AF in general practice. We performed radial pulse palpation, followed by electronic blood pressure measurement (WatchBP Home A) and handheld ECG (MyDiagnostick) in random order. If one or more index tests were positive, we performed a 12-lead ECG at shortest notice. Similarly, to limit verification bias, a random sample of patients with three negative index tests received this reference test. Additionally, we analysed the dataset using multiple imputation. We present pooled diagnostic parameters.

Setting: 47 general practices participated between September 2015 and August 2018.

Participants: In the electronic medical record system of the participating general practices (n=47), we randomly marked 200 patients of ≥65 years without AF. When they visited the practice for any reason, we invited them to participate. Exclusion criteria were terminal illness, inability to give informed consent or visit the practice or having a pacemaker or an implantable cardioverter-defibrillator.

Outcomes: Diagnostic accuracy of individual tests and test combinations to detect unknown AF.

Results: We included 4339 patients; 0.8% showed new AF. Sensitivity and specificity were 62.8% (range 43.1%-69.7%) and 91.8% (91.7%-91.8%) for radial pulse palpation, 70.0% (49.0%-80.6%) and 96.5% (96.3%-96.7%) for electronic blood pressure measurement and 90.1% (60.8%-100%) and 97.9% (97.8%-97.9%) for handheld ECG, respectively. Positive predictive values were 5.8% (5.3%-6.1%), 13.8% (12.2%-14.8%) and 25.2% (24.2%-25.8%), respectively. All negative predictive values were ≥99.7%.

Conclusion: In detecting AF, electronic blood pressure measurement (WatchBP Home A), but especially handheld ECG (MyDiagnostick) showed better diagnostic accuracy than radial pulse palpation.

Trial registration number: Netherlands Trial Register No. NL4776 (old NTR4914).

Keywords: cardiology; pacing & electrophysiology; preventive medicine.

Figure 1

The three index tests. (A) Radial pulse palpation. (B) WatchBP Home A, an automatic blood pressure monitor with atrial fibrillation detection algorithm. (C) MyDiagnostick, a handheld single-lead ECG device with atrial fibrillation detection algorithm.

Figure 2

Patients receiving index tests and their results. *Terminally ill, unable to give informed consent, unable to visit the practice, pacemaker/ICD, previous diagnosis of atrial fibrillation. ^†We included 4339 patients in the diagnostic accuracy study and 4106 in the randomised controlled trial. The screening of 233 patients occurred after the end of the study year and therefore they were not eligible for the randomised controlled trial. However, we did include them in the diagnostic accuracy study. ^‡An ‘AFIB’ icon appears on the screen in case of suspected atrial fibrillation. ^§A red light is indicative of atrial fibrillation, whereas a green light is not. ¶A random sample of patients with all performed tests negative received a 12-lead ECG.

Figure 3

Venn diagram* depicting the positive test results of the three index tests (n=526/4339†), including the distribution of patients with atrial fibrillation (AF) (n=30). *Created with Pacific Northwest National Laboratory software from omics.pnl.gov. †12-Lead ECG results were available for 485 out of 526 patients.