Subclinical Atrial Fibrillation in Older Patients
Bibliographic record
Abstract
Background: Long-term continuous electrocardiographic monitoring shows a substantial prevalence of asymptomatic, subclinical atrial fibrillation (SCAF) in patients with pacemakers and patients with cryptogenic stroke. Whether SCAF is also common in other patients without these conditions is unknown. Methods: We implanted subcutaneous electrocardiographic monitors (St. Jude CONFIRM-AF) in patients ≥65 years of age attending cardiovascular or neurology outpatient clinics if they had no history of atrial fibrillation but had any of the following: CHA 2 DS 2 -VASc score of ≥2, sleep apnea, or body mass index >30 kg/m 2 . Eligibility also required either left atrial enlargement (≥4.4 cm or volume ≥58 mL) or increased (≥290 pg/mL) serum NT-proBNP (N-terminal pro–B-type natriuretic peptide). Patients were monitored for SCAF lasting ≥5 minutes. Results: Two hundred fifty-six patients were followed up for 16.3±3.8 months. Baseline age was 74±6 years; mean CHA 2 DS 2 -VASc score was 4.1±1.4; left atrial diameter averaged 4.7±0.8 cm; and 48% had a prior stroke, transient ischemic attack, or systemic embolism. SCAF ≥5 minutes was detected in 90 patients (detection rate, 34.4%/y; 95% confidence interval [CI], 27.7–42.3). Baseline predictors of SCAF were increased age (hazard ratio [HR] per decade, 1.55; 95% CI, 1.11–2.15), left atrial dimension (HR per centimeter diameter, 1.43; 95% CI, 1.09–1.86), and blood pressure (HR per 10 mm Hg, 0.87; 95% CI, 0.78–0.98), but not prior stroke. The rate of occurrence of SCAF in those with a history of stroke, systemic embolism, or transient ischemic attack was 39.4%/y versus 30.3%/y without ( P =0.32). The cumulative SCAF detection rate was higher (51.9%/y) in those with left atrial volume above the median value of 73.5 mL. Conclusions: SCAF is frequently detected by continuous electrocardiographic monitoring in older patients without a history of atrial fibrillation who are attending outpatient cardiology and neurology clinics. Its clinical significance is unclear. Clinical Trial Registration: URL: http://www.clinicaltrials.gov . Unique identifier: NCT01694394.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".