Frequent premature atrial complexes and risk of concurrent atrial fibrillation
Bibliographic record
Abstract
Abstract Background Premature atrial complexes (PACs) predict incident atrial fibrillation (AF) in long-term follow-up studies. It is unclear whether frequent PACs on ambulatory ECG recordings indicate a higher likelihood of concurrent, undiagnosed AF. Furthermore, the reproducibility of a 24 h PAC count is unclear. Objectives To determine if frequent PACs on 24 h ambulatory ECG monitoring predicts concurrent AF during subsequent, prolonged ECG monitoring and to assess the diagnostic reliability of PAC counts on a 24 hour ECG recording. Methods AF was defined as ≥30 seconds of irregular rhythm without P waves, which was detected by a proprietary algorithm and manually verified. The proportion of AF occurrence during the remainder of the monitoring period was calculated for pre-specified levels of PACs during the first 24 h, and a function describing the association was fitted. The diagnostic reproducibility of a 24 h PAC count was assessed by calculating the likelihood of a PAC count ≥1000/day during the entire monitoring duration for prespecified PAC count levels during the first 24h. Results The study population comprised 20,973 patients (41% men, mean age 69.5 years) who had recorded an ambulatory ECG with a monitoring duration of 4–30 days in the United States during the year 2017 (median monitoring duration 16 days). AF was detected in 2,029 (9.7%) of patients and the median time to first occurrence of AF was 5 days. PAC frequency during the first 24 h was associated with AF during the monitoring period beyond the first 24 h, increasing steadily from 4.2% among those with 0–5 PACs, to a plateau around 17% among those with 250–1000 PACs per day and above. (Fig. 1A). The reproducibility of low PAC counts was good. Only 5.5% of patients with 0–5 PACs during the first 24 h of monitoring (31.8% of the population), had ≥1000 PACs on an alternate monitoring day. In contrast, among subjects with 100 PACs the probability of a day with ≥1000 PACs was close to 50% (Fig. 1B). Conclusion In patients undergoing ambulatory ECG monitoring, frequent PACs during the first 24 h indicate a higher likelihood of AF occurrence during subsequent days of monitoring. Less than 5 PACs during the first 24 h indicate a low probability of AF or frequent PACs on a subsequent day of ECG monitoring. Figure 1 Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): The Swedish Heart and Lung Foundation; The Swedish Heart and Lung Association
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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 | 0.001 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".