This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Effects of Fish Oil on Post Ablation Arrhythmias (NCT00791089), a randomized phase 4 study. The primary outcome is Number of Participants With Normal Sinus Rhythm (Freedom From Atrial Arrhythmias).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00791089 |
| Phase | Phase 4 |
| Condition | Atrial Fibrillation |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Michigan |
| Results posted | Yes |
2. Clinical Question
Population
Patients with atrial fibrillation undergoing radiofrequency catheter ablation. The registry record reports enrollment of 12, but further eligibility criteria and participant characteristics are not reported in the registry record.
Intervention
The treatment arm received omega-3 fatty acids, described as EPA+DHA 4 gram/day, for 4 weeks before and 3 months after ablation.
Comparator
The control arm received placebo and no omega-3 fatty acids, alongside ablation.
Primary question
At 6 months, how many participants had normal sinus rhythm, defined in the record as freedom from atrial arrhythmias with or without antiarrhythmic drug therapy? The stated aim also concerns early recurrences within 30 days and longer-term rhythm maintenance, but comparative results for these questions are not reported in the registry record.
The clinical question is whether peri-operative omega-3 treatment is associated with rhythm outcomes after ablation. Because the registry lists a placebo arm, the planned comparison is treatment against placebo in patients receiving ablation. It does not describe a comparison of ablation against no ablation. The registry record does not report a primary-outcome analysis, so it does not establish how the groups compared on the six-month endpoint. Participant characteristics, eligibility details, and the precise analysis population are not reported in the registry record.
3. Trial Design
This was a Phase 4, randomized, parallel-group trial with single masking. The sponsor was the University of Michigan. Enrollment was 12, and the registry status is terminated. The study start is listed as 2008-11 and primary completion as 2009-12.
Both arms involved radiofrequency catheter ablation for atrial fibrillation. The treatment arm description specifies omega-3 fatty acids (EPA+DHA 4 gram/day) for 4 weeks before and 3 months after the procedure. The control arm description says participants received placebo and no omega-3 fatty acids. The intervention listings name LOVAZA Omega 3-acid ethyl esters, LOVAZA, and placebo. The record does not clarify the distinction between the two LOVAZA entries. Who was masked is not reported in the registry record; “single” masking alone does not identify whether participants, clinicians, outcome assessors, or another group was masked.
Random allocation is intended to make treatment groups comparable on average, while a parallel design assigns each participant to one arm. These are general design principles, not evidence that groups in this small trial were balanced. The registry does not report the allocation sequence method, concealment procedures, reasons for termination, or a sample-size justification. A study-specific statistical analysis plan is not reported in the registry record.
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.
Before assignment: All of the 12 participants were assigned to an intervention, but none completed all aspects of the study, because of study termination due to funding withdrawal. Still, basic baseline and outcome measure data was available for 11 of the 12, as noted below.
Overall Study
| Stage | Fish Oil, Ablation, Sinus Rhythm | Placebo, Ablation, Sinus Rhythm |
|---|---|---|
| STARTED | 6 | 6 |
| Began Actually Taking Fish Oil or Placeb | 6 | 5 |
| Six-month Data Collected | 6 | 5 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 6 | 6 |
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.
Population: Baseline analysis is provided for all persons who actually began their assignment.
| Characteristic | Unit | Fish Oil, Ablation | Placebo, Ablation, Sinus Rhythm | Total |
|---|---|---|---|---|
| Participants analysed | 6 | 5 | 11 | |
| Age, Continuous | years | 56 (43 to 64) | 48.8 (26 to 65) | 52.7 (26 to 65) |
| Sex: Female, Male: Female | Participants | 0 | 1 | 1 |
| Sex: Female, Male: Male | Participants | 6 | 4 | 10 |
| Region of Enrollment: United States | participants | 6 | 5 | 12 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Normal Sinus Rhythm (Freedom From Atrial Arrhythmias), measured over 6 months.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The listed primary endpoint is the number of participants with normal sinus rhythm, described as freedom from atrial arrhythmias, at 6 months. Its definition includes absence of atrial arrhythmias with or without antiarrhythmic drug (AAD) therapy. The record also refers to “the two lines,” but the meaning of those lines and the precise outcome categories are not available in the registry record.
This endpoint is a participant count: it classifies participants according to whether they meet the rhythm definition at the specified follow-up. In general, a binary outcome is useful because it expresses whether a defined event or state occurred, rather than measuring the degree of change on a continuous scale. However, the registry identifies this outcome as having several categories or time points and does not reduce it to one comparison. The actual category-level results, denominators for the primary endpoint, and any treatment-effect estimate are not reported in the registry record.
Because the definition allows assessment with or without AAD therapy, the endpoint does not by itself distinguish rhythm status attributable to ablation alone from rhythm status while using medication. The registry does not report a separate result by AAD use.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a randomized comparison of omega-3 fatty acids and placebo around ablation, but it does not report a primary-outcome analysis. It therefore supplies no comparative estimate for the six-month normal-sinus-rhythm endpoint, no uncertainty interval, and no statistical test for that endpoint. There is no basis in the record for describing the size or precision of a treatment-group difference.
Enrollment was 12. That total is important context for interpreting the record, but it cannot substitute for the outcome-group counts or an estimate with uncertainty. The numbers of participants assigned to each arm and included in the primary analysis are not reported in the registry record. Nor are losses to follow-up, exclusions, or the handling of missing endpoint data reported. Without those details, it is not possible to determine which participants contributed to the outcome or whether the analysis retained the randomized groups.
The stated primary endpoint is at 6 months. The brief study summary also describes interest in early atrial-arrhythmia recurrences within 30 days and longer-term maintenance of sinus rhythm. Comparative results for those outcomes are not reported in the registry record. The study is marked terminated, but the reason for termination is not reported in the registry record. Termination status alone does not explain whether planned follow-up was completed or why the record lacks outcome analyses.
The adverse-event entries are descriptive counts. In the fish-oil arm, 1 participant is listed with a serious adverse event and 1 with another adverse event; in the placebo arm, the corresponding counts are 0 and 3. Deaths are listed as 0 in each arm. The registry also lists Cardiac Tamponnade at 16.7% among the top serious terms, but does not identify that term by treatment group in the displayed information. These entries do not provide a treatment-effect estimate for safety, and the small enrollment limits how much can be inferred from the counts.
In general, an estimate and its confidence interval help communicate both the direction and precision of a comparison. Neither is reported for the primary endpoint. No p-value or adjusted analysis is reported either. As a result, the registry record supports description of the design and listed counts, not a conclusion about the comparative rhythm outcome.
9. Statistical Methods Explained
The registry identifies a randomized, single-masked, parallel-group Phase 4 study and a participant-count outcome. It does not provide the primary-outcome analysis. The concepts below explain how such a trial might be analyzed in general; they do not describe analyses confirmed to have been conducted in this trial.
What does randomization contribute?
In general, random assignment is used to reduce systematic differences between groups at the point of assignment. If allocation is implemented as planned and participants are analyzed appropriately, the groups can be compared as randomized. Randomization does not guarantee that a small study will have similar groups on every characteristic. This record reports enrollment of 12, but participant characteristics and arm-specific enrollment are not reported in the registry record. The allocation sequence and concealment procedures are also not reported in the registry record.
In a parallel-group design, each participant is assigned to one treatment group rather than crossing over between treatments. The described comparison is omega-3 fatty acids versus placebo, with both arms receiving ablation. The record labels masking as single, but the masked parties are not reported in the registry record. Masking can, in general, reduce the influence of treatment knowledge on behavior, assessment, or reporting; its practical value depends on who is masked and how outcomes are measured.
What does a participant count represent?
The primary endpoint is a count of participants meeting the record’s definition of normal sinus rhythm at 6 months. In general, this is a categorical outcome: each participant is classified according to whether the stated condition is met. A group count is interpretable only alongside the relevant denominator and a clear rule for classifying participants. The registry record does not report the primary endpoint’s group counts, analysis denominators, or category-specific results. The note that the endpoint has several categories or time points and was not reduced to one comparison further limits interpretation of a single treatment contrast.
When a binary outcome is reported, an analysis may compare group proportions or use a model that estimates a treatment contrast. The appropriate contrast depends on the endpoint definition, trial plan, and data structure. No such primary-outcome estimate or model is reported in the registry record. It would be inappropriate to infer a risk difference, risk ratio, odds ratio, or other effect from the information available.
How should uncertainty be understood?
General statistical principle: a confidence interval gives a range of values compatible with the data under the analysis assumptions and communicates the precision of an estimate. A wide interval indicates less precision than a narrow interval; an interval’s interpretation also depends on the estimator and method used. No confidence interval for the primary endpoint is reported in the registry record, so the precision of any treatment comparison cannot be assessed.
General statistical principle: a p-value measures how incompatible data are with a specified null model, under the assumptions of the test. It is not the probability that a treatment is effective, nor does it convey the magnitude or clinical importance of an effect. A primary-outcome p-value is not reported in the registry record. Thus there is no posted significance test to interpret.
What can the planning illustration establish?
The record describes sample-size calculations as planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect and distinguishes calculations reported per arm from time-to-event calculations reported as a total. These are assumptions for an illustration, not evidence of the trial’s original design or justification. The registry does not report the trial’s own sample-size justification or the planning results in the information available for this analysis. Such illustrations are not observed power and cannot replace an outcome estimate or uncertainty interval.
General statistical principle: sample-size planning asks how much information a future study might need under specified assumptions. Power is a design property conditional on those assumptions, not a measure of whether a completed study has proved a hypothesis. Because the primary outcome analysis is absent, a planning calculation cannot establish the precision or reliability of the trial’s actual findings.
Why do analysis choices matter?
The endpoint definition permits normal sinus rhythm status with or without AAD therapy. In general, a study should specify whether medication use is part of the endpoint, an adjustment variable, a separate outcome, or a treatment after randomization that is handled in another way. Those choices can change the estimand—the precise treatment effect the analysis is intended to describe. The registry record does not report an estimand or a separate analysis by AAD use.
General statistical principle: an analysis should also make clear which randomized participants are included, how missing observations are handled, and whether the model accounts for the design. These details affect interpretation and reproducibility. The registry record does not report the analysis population, missing-data method, or model for the primary endpoint. Consequently, no claim about an intention-to-treat, per-protocol, or other analysis can be made from the record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure, but the primary-outcome description is flagged as involving several categories or time points and not being reduced to one comparison. The registry record does not report how those categories or times were analyzed, which comparison was prioritized, or whether any multiplicity adjustment was used. When several outcomes, time points, or contrasts are tested, general statistical practice recognizes that the chance of at least one false-positive finding can increase. Methods for controlling that risk depend on the analysis plan and are not reported in the registry record.
The primary endpoint is described at 6 months, while the study summary also refers to early recurrences within 30 days and longer-term rhythm maintenance. The relation between these aims and the listed outcome measure is not fully explained in the registry record. A prespecified hierarchy or distinction between primary and secondary analyses is not reported.
Missing-data handling and analysis populations are not reported in the registry record. The record does not state how many participants had six-month endpoint data, whether any participants withdrew or were excluded, or how missing rhythm assessments were treated. It also does not identify whether analysis followed randomized assignment or another population definition. These omissions prevent assessment of attrition, completeness, and the consequences of any exclusions. The reason for termination is not reported in the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Fish Oil, Ablation | 1 | 6 | 16.7% |
| Placebo, Ablation | 0 | 6 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Fish Oil, Ablation | 0 of 6 |
| Placebo, Ablation | 0 of 6 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Fish Oil, Ablation | 1 of 6 |
| Placebo, Ablation | 3 of 6 |
Most frequent serious adverse event terms
| Event term | Organ system | Fish Oil, Ablation | Placebo, Ablation |
|---|---|---|---|
| Cardiac Tamponnade | Surgical and medical procedures | 1 of 6 | 0 of 6 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Fish Oil, Ablation | Placebo, Ablation |
|---|---|---|---|
| Anxiety | Psychiatric disorders | 0 of 6 | 1 of 6 |
| Fluid gain | Surgical and medical procedures | 0 of 6 | 1 of 6 |
| Spot on Face | Skin and subcutaneous tissue disorders | 0 of 6 | 1 of 6 |
| Painful vericose veins | Blood and lymphatic system disorders | 0 of 6 | 1 of 6 |
| Bradycardia | Cardiac disorders | 0 of 6 | 1 of 6 |
| pneumonitis | Surgical and medical procedures | 1 of 6 | 0 of 6 |
Serious events with the highest arm-level rate: cardiac tamponnade (16.7%).
The registry lists serious adverse events for 1 of 6 participants in the Fish Oil, Ablation group and 0 of 6 in the Placebo, Ablation group. Other adverse events are listed for 1 of 6 and 3 of 6, respectively. Deaths are listed as 0 in both groups. These are the posted counts; they should not be read as a complete description of event timing, recurrence, severity beyond the serious/non-serious distinction, or causal attribution.
Cardiac Tamponnade appears among the top serious terms with a listed value of 16.7%. The record does not specify the treatment group associated with that term in the information, so it should not be assigned to either arm. The registry also does not report detailed event narratives or an analysis comparing safety between groups.
General statistical context: with small groups, a count describes what was recorded but gives limited precision about how often an event might occur in a broader population. The absence of a listed death does not establish absence of risk. These data are descriptive and do not by themselves establish whether an event was caused by study treatment or ablation.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized, parallel-group study was registered to examine omega-3 fatty acids around ablation for atrial fibrillation. It describes a placebo comparator, the treatment schedule, and a six-month rhythm endpoint. It also lists adverse-event counts and marks the study as terminated. Those details make the trial’s question and some aspects of its design clear.
The record does not report a primary-outcome analysis or comparative rhythm results. It therefore cannot show whether the treatment and placebo groups differed in the number of participants meeting the rhythm definition, or how precisely any such difference was estimated. The record also does not report results for the early-recurrence aim described in the summary. A treatment effect, its direction, and its magnitude cannot be inferred from the design alone.
The adverse-event counts describe entries in the registry; they do not establish a causal relationship or a comparative safety effect. The serious-event term listed at 16.7% is not identified by arm in the available record. With enrollment of 12, the counts also represent a small set of participants, and the registry does not provide the detail needed to assess completeness or follow-up.
General statistical principle: an absent analysis is not evidence that groups had the same outcomes, and a trial’s termination status is not itself an outcome. Likewise, a planning illustration is not an observed result and does not answer the clinical question. The appropriate interpretation is limited to the design information and counts actually posted; the primary efficacy question remains unanswered by the registry results.
13. Why This Trial Matters Statistically
This trial matters statistically because it illustrates the distinction between a clearly stated study question and an interpretable estimate of the answer. The registry identifies a randomized comparison around ablation and defines a six-month rhythm outcome. Yet it does not report the group results or an analysis for that endpoint. Without those elements, readers cannot assess the estimated contrast, its uncertainty, or whether the endpoint’s multiple categories and time points were handled consistently with a prespecified plan.
The small enrollment also makes transparent reporting especially important. Counts alone are useful descriptive information, but they do not convey the precision of a treatment comparison unless paired with appropriate denominators and an analysis. The record does not report the primary endpoint denominators or the analysis population. These are not technical details detached from interpretation: they determine which participants and observations the result represents.
The case also highlights why adverse-event entries should be read separately from efficacy results. The registry gives arm-level serious and other event counts, but it does not provide an arm-specific attribution for the listed serious term or a comparative safety analysis. Descriptive counts can support careful reporting without justifying broader claims.
Finally, the planning illustration is explicitly distinct from the trial’s own design justification. In general, planned sample size calculations depend on assumptions, whereas completed-trial interpretation depends on observed data and uncertainty. The registry does not provide the outcome analysis needed to connect the design to a conclusion. A transparent account of analyses, missing observations, and outcome categories would be necessary for a fuller statistical assessment.
14. 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 registry marks the study as terminated, but the reason for termination is not reported in the registry record. Enrollment is 12, and the record does not report arm-specific enrollment for the primary endpoint, participant flow, or follow-up completeness. These omissions make it difficult to understand the extent of information available for the planned six-month comparison.
The primary endpoint description refers to freedom from atrial arrhythmias with or without AAD therapy and mentions “the two lines,” but the registry does not explain those lines or provide the corresponding outcome results. The record also flags multiple categories or time points without a single comparison. The analysis plan for handling these elements is not reported in the registry record.
The record does not report participant characteristics, eligibility criteria, the allocation procedure, who was masked, or the analysis population. It also does not provide a sample-size justification, a missing-data strategy, or a primary-outcome model. These limitations restrict assessment of comparability, risk of bias, and statistical precision. The listed safety information is limited to counts and a serious-event term; detailed event descriptions, timing, and attribution are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effects of Fish Oil on Post Ablation Arrhythmias — NCT00791089.
- Registry record last updated 2017-09-12; status last verified 2017-08.
- Results first posted 2017-05-05.
- 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.
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18. Record Summary
NCT00791089 is a Phase 4 randomized, single-masked, parallel-group trial sponsored by the University of Michigan. It enrolled 12 participants and is listed as terminated. The study compared omega-3 fatty acids with placebo around radiofrequency catheter ablation for atrial fibrillation. The treatment description specifies EPA+DHA 4 gram/day for 4 weeks before and 3 months after ablation.
The primary outcome is the number of participants with normal sinus rhythm at 6 months, defined as freedom from atrial arrhythmias with or without AAD therapy. The registry record does not report a primary-outcome analysis or comparative rhythm results. Adverse-event entries list serious events in 1 participant in the fish-oil group and 0 in the placebo group, other events in 1 and 3, and deaths of 0 in each group. The reason for termination and the primary endpoint analysis details are not reported in the registry record.