Prediction and Maintenance of Sinus Rhythm Among Atrial Fibrillation Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Prediction and Maintenance of Sinus Rhythm Among Atrial Fibrillation Patients (NCT04313296), a na na study. The primary outcome is Number of Patients With a Relationship Between Left Atrial Global Longitudinal Strain and the Maintenance of Sinus Rhythm After Cardioversion.

2. Clinical Question

The study rationale focuses on whether left atrial strain measurements could be informative about maintaining normal sinus rhythm after cardioversion among patients with atrial fibrillation. The registry’s brief summary describes the aim as investigating predictive measures of left atrial global longitudinal strain. However, the primary outcome is titled as a number of patients with a relationship between strain and maintenance of sinus rhythm, while its description focuses on strain compared with the duration of rhythm maintenance. These descriptions do not specify a statistical definition for what constitutes a relationship or how a patient would be counted as having one.

The record does not report a comparator arm, a threshold for strain, or a rule for classifying rhythm maintenance. It therefore describes an observational relationship of interest, but does not establish from the recorded information how the investigators intended to quantify or test that relationship. No outcome findings are reported in the registry record.

3. Trial Design

The registry identifies this as a single-group study with allocation listed as not applicable and masking listed as none. The arm description refers to patients identified at PBMC with a documented diagnosis of atrial fibrillation at any point in time who had undergone any cardioversion. There is no like-for-like control group described, and the record does not present the study as a randomized comparison.

The listed intervention is a unique measurement using the commercial TOMTEC-ARENA software program. The measurement of interest is left atrial global longitudinal strain. The primary outcome description relates that measurement to the duration, in months, that sinus rhythm was maintained following elective cardioversion. The population and outcome descriptions differ in their wording about cardioversion: the arm description says any cardioversion, whereas the primary outcome description specifies elective cardioversion. The registry does not explain this difference.

Enrollment is recorded as 209. The study start date is 2020-05-01, and the primary completion date is 2022-09-06. The status is terminated. The reason for termination is not reported in the registry record. The phase is listed as NA, which is consistent with the record not presenting this as a phase-based drug trial; no further explanation is recorded.

With a single group and no comparator, the design can address an association between the strain measurement and subsequent rhythm duration only if those measurements and outcomes are defined and analysed appropriately. It cannot, by itself, separate that association from other differences among patients or establish that a measurement causes an outcome. The registry record does not provide a protocol, detailed eligibility criteria, recruitment flow, or an account of how the study was conducted. It also does not report whether the registered enrollment corresponds to the number assessed for the primary outcome.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number of Patients With a Relationship Between Left Atrial Global Longitudinal Strain and the Maintenance of Sinus Rhythm After Cardioversion, measured over 12 months.

The primary endpoint is titled as the number of patients with a relationship between left atrial global longitudinal strain and maintenance of sinus rhythm after cardioversion. Its description says strain was measured using TOMTEC-ARENA and compared with the duration of sinus rhythm maintenance. The stated timeframe is 12 months, and the unit is participants. In practical terms, this outcome appears intended to connect a measured cardiac imaging feature with how long sinus rhythm was maintained after cardioversion.

Such an endpoint is relevant to a prediction question because a measurement may be evaluated for whether it is associated with a later clinical state or its duration. A carefully defined association could help characterize whether variation in the measurement corresponds to variation in rhythm maintenance. This is a general explanation of the statistical purpose, not a conclusion about the study’s findings.

The registry record does not specify how strain was summarized, how duration was determined, or what counted as a patient having a relationship. It does not state whether rhythm recurrence was confirmed by a particular monitoring method, how patients with incomplete follow-up were handled, or how the relationship would be tested. Although the outcome is described as a number of participants, no observed count or estimate is reported in the registry record. The endpoint therefore identifies the intended topic of measurement but does not provide enough detail to reproduce its operational definition or interpret an observed estimate.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What can the design establish? The study is registered as single-group, with allocation listed as not applicable and masking as none. In general, a single-group study can describe measurements and outcomes among the participants studied. If an association analysis is conducted, it can estimate how a measurement varies with an outcome in that group. Without a comparator group or randomized allocation, such an association does not isolate a causal effect. The registry record does not report an analysis model or an adjustment strategy, so no specific statistical procedure can be attributed to this study.

How would an association be represented?

In general, an analysis relating a continuous measurement to a duration could use an estimate that describes the direction and strength of association, or a model suited to the outcome’s distribution and follow-up structure. The choice depends on how the measurement and duration were collected, whether the duration is fully observed, and whether relevant assumptions are reasonable. The record does not identify a planned estimate, model, or assumptions. It also does not state whether the investigators planned to treat duration as a continuous outcome or use a time-to-event approach.

These distinctions matter because a duration recorded for every participant is not necessarily analysed in the same way as time until an event when some participants have no observed event by the end of follow-up. In general, time-to-event methods can account for incomplete observation through censoring, provided that the event and censoring processes are appropriately defined. The registry does not say whether rhythm recurrence was treated as an event, whether censoring occurred, or whether time-to-event methods were used. The 12 months is the registered timeframe; it is not a reported follow-up distribution or evidence that every participant was observed for that duration.

What does a confidence interval add?

In general, a point estimate gives a single summary of an association, while a confidence interval communicates its statistical uncertainty under the analysis assumptions. A narrow interval indicates greater precision than a wide interval, although precision does not establish that an estimate is unbiased or clinically important. A p-value, when used, addresses compatibility between the data and a specified null hypothesis under the test assumptions; it does not measure the size or practical importance of an association. The registry record reports no point estimate, confidence interval, or p-value for the primary endpoint, so these interpretations cannot be applied to the study’s results.

The registry’s primary outcome is classified as binary and its parameter as a number, with the outcome meaning described as participants with an event (counts). The written endpoint title also refers to a number of patients with a relationship, while the description refers to duration in months. These classifications and descriptions do not give a complete analysis specification. In particular, no rule is reported for converting the relationship between strain and duration into a binary participant-level result.

Why do outcome definitions matter?

A reproducible analysis requires clear definitions for the measurement, outcome, and analysis population. For this question, readers would need to know how left atrial strain was calculated, what time origin was used after cardioversion, how maintenance or loss of sinus rhythm was assessed, and how the duration was determined. If a categorical outcome was planned, the classification rule would be needed as well. The registry record does not report these details. Their absence limits replication and makes it difficult to compare any eventual results with other studies.

In general, measurement error can weaken or distort an observed association. A software-derived strain value may depend on image acquisition, image quality, processing, and the analysis settings used. This is a general consideration for imaging measurements, not a reported problem in this study. The registry identifies TOMTEC-ARENA as the software but does not describe acquisition procedures, quality control, reader training, or reproducibility assessment.

What about the planning calculations?

Planning calculations associated with the posted results are illustrations, not the trial’s own design justification. Their stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of an observed effect. These are planning assumptions and do not describe the registered single-group design. They should not be read as observed power, as evidence that a particular effect was found, or as proof that the study was designed around a particular sample-size target. The registry record does not report a sample-size justification for the study itself.

In general, planning estimates depend on assumptions about the effect size, variability, outcome distribution, and analysis. If those assumptions do not match the study’s actual design or data, the resulting figures may not represent the study’s ability to answer its question. Because the registry does not report a primary estimate or its uncertainty, the observed effect used in any such illustration cannot be evaluated from the registry record. No new study-specific power conclusion follows from the available information.

10. Multiplicity, Missing Data and Analysis Populations

The registry record does not report a multiplicity plan. Multiplicity arises when researchers test or estimate several outcomes, subgroups, timepoints, or alternative models, increasing the chance that some result appears notable by chance. In general, a prespecified primary outcome and analysis help readers distinguish the main confirmatory question from exploratory work. Here, the record identifies a primary outcome but does not report how multiple analyses, if any, would be handled. No additional outcome analyses are reported in the registry record.

Missing-data methods are also not reported in the registry record. This is important because a participant may have a strain measurement but incomplete rhythm follow-up, or may have follow-up that ends before the outcome is determined. In general, excluding incomplete records, imputing missing values, or using methods that account for incomplete follow-up can lead to different estimates, and each approach relies on assumptions. The registry does not state how incomplete measurements, unavailable records, or loss to follow-up were addressed. It also does not report how many participants had data available for the primary endpoint.

The analysis population is not defined in the registry record. Enrollment is recorded as 209, but that figure should not be treated as the primary analysis population or as a count of participants with complete data. The record does not describe exclusions after enrollment, eligibility verification, or an intention-to-analyse approach. It also does not report a participant flow or the number contributing to an outcome estimate.

These omissions prevent assessment of whether missingness or analytic choices could have influenced the reported relationship. They do not establish that missing data or multiplicity affected the study; the relevant methods and results are simply not reported in the registry record.

11. What the Result Does, and Does Not, Mean

The record establishes that the study was designed to investigate a relationship between left atrial global longitudinal strain and the duration of sinus rhythm maintenance after cardioversion. It identifies TOMTEC-ARENA as the measurement software and gives 12 months as the primary outcome timeframe. It also records a single-group design, enrollment of 209, and terminated status. These are features of the registered study, not evidence of an observed association.

The record does not report the outcome count, an estimate of association, its uncertainty, or an analysis result. It therefore cannot show whether strain was associated with rhythm duration, whether any relationship was positive or negative, or whether the estimate was precise. It also cannot establish that strain predicts an individual patient’s outcome. Prediction requires assessment of how well a model performs, not merely a stated interest in a relationship; performance results are not reported in the registry record.

Even if an association were observed, a single-group design would not by itself show that changing strain changes rhythm maintenance. Association and causation are different questions. A measurement may correlate with an outcome because of other factors, and the registered information does not describe adjustment methods or other analyses that could address those possibilities. The record also does not provide enough outcome-definition detail to determine how any association would be interpreted.

The study’s terminated status does not explain why it ended or whether the intended analyses were completed. The reason for termination is not reported in the registry record. Readers should therefore distinguish the study’s stated research objective from findings that are not recorded. No conclusion about clinical benefit, harm, or treatment choice follows from the registry information.

12. Why This Trial Matters Statistically

Statistically, the study raises a measurement-and-outcome question: whether left atrial global longitudinal strain corresponds to how long sinus rhythm is maintained after cardioversion. This is a distinct question from whether a cardioversion strategy is better than another strategy. The registered single-group design and the absence of a comparator make that distinction central to interpretation.

The record also illustrates why a precise endpoint definition matters. “Number of patients with a relationship” suggests a participant-level count, while the outcome description refers to comparing a measurement with duration in months. Those formulations may represent different analytic targets. Without a definition of the relationship, a reader cannot determine how the endpoint would be calculated or reproduced. Clear definitions of rhythm status, follow-up time, and incomplete observations would also be important for a reliable analysis.

Prediction questions require more than an association estimate. In general, a useful prediction assessment considers how well predictions agree with observed outcomes and whether performance is likely to carry over to other patients. The registry record does not report a prediction model, validation approach, or performance results. It is therefore not possible to judge predictive accuracy from the registered information.

The lack of reported results and analysis methods limits statistical interpretation, but it does not erase the scientific question. Rather, it identifies what readers would need to assess the evidence: a clear endpoint definition, analysis population, statistical approach, estimates with uncertainty, and an account of missing data. The registry record does not report those elements for the primary outcome, so the stated aim cannot be translated into a finding about the strength or usefulness of the measurement.

13. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The primary limitation for interpreting this specific study is that the registry record does not report primary outcome results or a statistical analysis. No count of patients with the endpoint, association estimate, confidence interval, or p-value is recorded. The study’s terminated status is given, but the reason is not reported in the registry record.

The endpoint description is not operationally complete. It refers to a number of patients with a relationship between strain and sinus rhythm maintenance, but does not define what qualifies as a relationship or how that participant-level count would be derived. It also does not specify how strain values, rhythm status, or duration were measured in practice. The timeframe is stated as 12 months, but the record does not describe the timing or completeness of follow-up.

The population description leaves further uncertainty. The arm description includes patients with atrial fibrillation at any point in time who had undergone any cardioversion, while the primary outcome description refers to elective cardioversion. The registry does not explain this difference or give detailed eligibility criteria. It also does not say how many enrolled participants had data suitable for the primary analysis.

The single-group design has no separate comparator, so it cannot provide a randomized between-group contrast. The record does not report adjustment methods that might address other factors associated with strain or rhythm duration. Missing-data handling, analysis populations, multiplicity procedures, and sample-size justification are not reported in the registry record. These limitations concern what can be concluded from the registry information; they do not establish that the study was conducted incorrectly.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Prediction and Maintenance of Sinus Rhythm Among Atrial Fibrillation Patients — NCT04313296.
• Registry record last updated 2023-08-14; status last verified 2023-07.
• Results first posted 2023-08-14.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

17. Record Summary

The registry record describes NCT04313296, titled “Prediction and Maintenance of Sinus Rhythm Among Atrial Fibrillation Patients.” The sponsor is Crystal Blake-Parlin. The study is listed as a single-group, unmasked study, with allocation marked not applicable and phase listed as NA. Enrollment is recorded as 209. The start date is 2020-05-01, the primary completion date is 2022-09-06, and the status is terminated.

The listed intervention is a unique left atrial global longitudinal strain measurement using TOMTEC-ARENA. The primary outcome concerns the number of patients with a relationship between strain and maintenance of sinus rhythm after cardioversion, with a 12-month timeframe. The registry record does not report a primary outcome result, analysis method, reason for termination, or detailed missing-data approach. No analysis entries are reported.