Related Experiment Video
Updated: Nov 2, 2025

Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation
Published on: July 20, 2022
Application of a machine learning algorithm for detection of atrial fibrillation in secondary care
Kevin G Pollock1, Sara Sekelj2, Ellie Johnston2
1Bristol-Myers Squibb Pharmaceuticals Ltd, Uxbridge Business Park, Sanderson Road, Uxbridge, Middlesex UB8 1DH, UK.
Insights
Machine learning algorithms can identify undiagnosed atrial fibrillation (AF) in secondary care. This study found an algorithm successfully detected thousands of new AF cases, improving patient identification and stroke risk management.
Area of Science:
- Cardiology
- Medical Informatics
- Machine Learning
Background:
- Atrial fibrillation (AF) is a prevalent heart arrhythmia increasing stroke risk.
- Current AF detection methods, like electrocardiograms, can be inefficient for high-risk individuals.
- Risk-prediction algorithms and machine learning (ML) show promise for improving AF diagnosis.
Purpose of the Study:
- To evaluate an AF-risk prediction algorithm's performance using linked primary and secondary care data.
- To identify patients with undiagnosed AF in secondary care who were missed in primary care.
- To assess the impact of newly identified AF cases on the algorithm's predictive accuracy.
Main Methods:
- Applied an ML-based AF-risk prediction algorithm to the DISCOVER database, linking primary and secondary care data.
- Analyzed algorithm performance in identifying patients with AF diagnoses solely in secondary care.
- Calculated algorithm sensitivity and specificity at a 7.4% risk threshold for patients aged 30 years and older.
Main Results:
- An additional 5,444 patients with AF diagnoses exclusively in secondary care were identified.
- The algorithm accepted 49.5% of these patients, correctly assigning 97.8% to the AF cohort.
- At a 7.4% risk threshold, algorithm sensitivity was 38% and specificity was 95%.
Conclusions:
- The ML algorithm effectively identifies previously undiagnosed atrial fibrillation in secondary care settings.
- Integrating secondary care data enhances AF detection, revealing a significant number of missed diagnoses.
- This approach offers a valuable tool for proactive AF identification and stroke risk mitigation.
Abstract:
Atrial fibrillation (AF) is the most common sustained heart arrhythmia and significantly increases risk of stroke. Opportunistic AF testing in high-risk patients typically requires frequent electrocardiogram tests to capture the arrhythmia. Risk-prediction algorithms may help to more accurately identify people with undiagnosed AF and machine learning (ML) may aid in the diagnosis of AF. Here, we applied an AF-risk prediction algorithm to secondary care data linked to primary care data in the DISCOVER database in order to evaluate changes in model performance, and identify patients not previously detected in primary care. We identified an additional 5,444 patients who had an AF diagnosis only in secondary care during the data extraction period. 2,696 (49.5%) were accepted by the algorithm and the algorithm correctly assigned 2,637 (97.8%) patients to the AF cohort. Using a risk threshold of 7.4% in patients aged ≥ 30 years, algorithm sensitivity and specificity was 38% and 95%, respectively. Approximately 15% of AF patients assigned to the AF cohort by the algorithm had a secondary care diagnosis with no record of AF in primary care. These additional patients did not substantially alter algorithm performance. The additional detection of previously undiagnosed AF patients in secondary care highlights unexpected potential utility of this ML algorithm.
Related Concept Videos
Pulse rhythm
Conversely, an irregular pulse pattern is termed dysrhythmia, stemming from disruptions in cardiac...
Dysrhythmias V: Evaluating Dysrhythmias
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
Dysrhythmias II: Classification of Tachyarrhythmias
Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...

