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 Post-Market Randomized Trial: Endoscopically- Guided Ablation vs. Radiofrequency Ablation (NCT01057394), a randomized phase 4 study. The primary outcome is Rate of Permanent Pulmonary Vein Isolation of EAS-AC Compared to EAM Guided Radiofrequency Ablation.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01057394 |
| Phase | Phase 4 |
| Condition | Paroxysmal Atrial Fibrillation |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 21 |
| Arms in the primary outcome | n/a |
| Lead sponsor | CardioFocus |
| Results posted | Yes |
2. Clinical Question
Population
Participants with paroxysmal atrial fibrillation enrolled in a post-market randomized trial. The record states that 21 participants were enrolled, 19 were treated, and 17 returned for the 3 month pulmonary vein remapping used to evaluate effectiveness.
Intervention
Visually guided pulmonary vein isolation using an endoscopic ablation system. The intervention is also described as endoscopically guided pulmonary vein isolation ablation.
Comparator
Pulmonary vein isolation using radiofrequency ablation guided by electroanatomical mapping. The registry describes this arm as radiofrequency ablation.
Primary question
How many initially isolated pulmonary veins remained isolated at 3 month remapping, comparing endoscopically guided ablation with electroanatomical-mapping-guided radiofrequency ablation?
The registry frames the broader purpose as comparing safety and chronic pulmonary vein isolation for the two ablation types. The named primary outcome concerns pulmonary veins, not a participant-level measure: its description counts initially isolated veins that remained isolated at remapping. The record states that 46/59 pulmonary veins were assessed for chronic isolation among participants who returned for effectiveness evaluation.
The clinical question therefore has two related but distinct parts. The primary endpoint concerns persistence of isolation at the pulmonary-vein level. Safety concerns adverse events among treated participants. The record does not report a numerical primary-outcome result or an analysis comparing the randomized groups, so the relative endpoint performance cannot be determined from the registry information.
3. Trial Design
The study is identified as a Phase 4, randomized, parallel-group trial with no masking. It is titled a post-market randomized trial and compares endoscopically guided ablation with radiofrequency ablation. CardioFocus is listed as the sponsor. The registry lists the start as 2009-12, primary completion as 2011-06, and status as terminated. It does not report why the trial was terminated.
The two interventions are devices. One arm used pulmonary vein isolation with visually guided ablation and an endoscopic ablation system; the other used pulmonary vein isolation with radiofrequency ablation. The primary outcome title describes comparison of EAS-AC with electroanatomical-mapping-guided radiofrequency ablation. The record does not explain the relationship between the EAS-AC label and the full intervention wording beyond these descriptions.
The enrollment figure is 21. The registry further reports that 19 participants were treated and that 17 of those treated participants returned for 3 month pulmonary vein remapping. Those returning participants were considered evaluable for effectiveness. The outcome description says 46/59 pulmonary veins were assessed for chronic isolation. These figures describe different stages and units of observation: enrolled and treated participants, returning participants, and pulmonary veins assessed.
Randomization supports a planned comparison between intervention groups, but the record does not give allocation details, concealment procedures, or a statistical analysis plan. Masking is listed as none. The record does not report whether allocation was stratified, how treatment adherence was handled, or whether the analysis followed an intention-to-treat approach. It also does not provide arm-specific participant counts for the primary endpoint.
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: The Sponsor stopped the study for business reasons before any participants were enrolled in the RF arm.
Overall Study
| Stage | Radiofrequency Ablation | Visually Guided Ablation |
|---|---|---|
| STARTED | 0 | 21 |
| COMPLETED | 0 | 19 |
| NOT COMPLETED | 0 | 2 |
Reasons for not completing this period:
| Reason | Radiofrequency Ablation | Visually Guided Ablation |
|---|---|---|
| Not eligible | 0 | 2 |
Analysis population for the primary outcome, as defined in the registry: Of the 21 enrolled participants, 19 were treated participants and 17 of the 19 came back for the 3 month PV remapping and were thus evaluable for effectiveness. This resulted in 46/59 (78%) pulmonary veins being assessed for chronic isolation.
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.
| Characteristic | Unit | Visually Guided Ablation |
|---|---|---|
| Participants analysed | 21 | |
| Age, Continuous | years | 59 (SD 8) |
| Sex: Female, Male: Female | Participants | 9 |
| Sex: Female, Male: Male | Participants | 12 |
| Region of Enrollment: Czech Republic | participants | 16 |
| Region of Enrollment: Italy | participants | 5 |
6. Primary Endpoint
The registry lists the primary outcome as Rate of Permanent Pulmonary Vein Isolation of EAS-AC Compared to EAM Guided Radiofrequency Ablation, measured over 3 Months.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | isolated pulmonary veins |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled as a rate of permanent pulmonary vein isolation, but the registry describes the measure as the number of initially isolated pulmonary veins that remained isolated at 3 month remapping. Its unit is treated pulmonary veins, and its parameter is recorded as a number. The timeframe is 3 Months.
This endpoint addresses whether electrical isolation was still present when veins were remapped after the initial ablation. It is used to assess chronic, rather than only immediate, isolation. As described, it counts veins that were initially isolated and remained isolated; it is not described as a count of participants who remained free of an outcome.
The record states that 17 treated participants returned for the remapping and were evaluable for effectiveness. It says 46/59 pulmonary veins were assessed for chronic isolation. However, it does not report the number of those veins that remained isolated in either treatment group, nor does it report a rate or between-group estimate. The endpoint definition and assessment population are available, but the numerical primary result is not reported in the registry record.
In general, a clearly defined endpoint helps connect the clinical question to the observed measurement. Here, the unit matters: veins assessed within the same participant may share characteristics. A statistical analysis should account for the endpoint’s structure, but the registry record does not state how any such dependence was handled.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes the trial question, the endpoint, and the population assessed, but it does not report the primary outcome values. In particular, it gives no group-specific count of pulmonary veins that remained isolated at 3 month remapping and no estimate of the difference between the ablation groups. As a result, the primary comparison cannot be interpreted quantitatively from the registry record.
The information about the effectiveness population should be read in its own units. The record reports 21 enrolled participants, 19 treated participants, and 17 who returned for remapping. It also reports 46/59 pulmonary veins assessed for chronic isolation. The participant counts describe trial participation and follow-up; the vein count describes the primary endpoint’s assessment unit. They should not be treated as interchangeable denominators.
The registry outcome title uses the word “rate,” while the outcome description specifies a number of veins. Without group-specific results, a numerator, or an analysis method, there is no reported rate or effect estimate to interpret. No confidence interval, hypothesis test, or statistical comparison is reported. The registry lists no analyses for the primary outcome.
For safety, the registry reports a visually guided ablation group with 19 participants at risk for serious adverse events and 2 affected. It lists 19 at risk and 0 affected for other adverse events in that group. The serious adverse event terms listed are pericardial effusion and groin bleed, each reported as 5.3%. These entries do not provide a comparative safety result: corresponding figures for the radiofrequency group are not reported in the registry record. The record also does not state whether any adverse event was considered related to treatment.
In general, estimates should be interpreted alongside their uncertainty. A confidence interval describes a range of values compatible with the data and the method used; without an estimate or interval, precision cannot be assessed. A p-value, if reported, would address compatibility with a specified statistical null model, not the size or clinical importance of an effect. Neither a p-value nor an interval is reported for the primary endpoint.
The trial status is terminated, but the record does not give a reason. It would be inappropriate to infer whether termination affected enrollment, follow-up, or the analysis. The absence of a posted primary comparison means the registry record does not establish a direction or magnitude of difference between treatments. It also does not establish that the approaches were equivalent.
9. Statistical Methods Explained
What is the endpoint’s unit?
The primary endpoint is defined at the pulmonary-vein level. The registry describes counting initially isolated veins that remained isolated at 3 month remapping. That differs from a participant-level outcome, such as counting participants with a specified result. The record says 46/59 pulmonary veins were assessed, while the effectiveness follow-up is described in participants: 17 treated participants returned for remapping. Keeping these units distinct is essential when reading any estimate or denominator.
In general, measurements from multiple veins within the same participant may be related. Treating every vein as if it were independent could make uncertainty estimates too narrow when outcomes within a participant are correlated. Methods for clustered or correlated observations can account for that structure. The registry record does not describe the statistical method used for the pulmonary-vein endpoint, so it is not possible to tell whether or how within-participant dependence was addressed.
What would a between-group estimate mean?
A comparative analysis would summarize how the endpoint differed between the randomized interventions. Depending on the prespecified analysis, that summary might be a difference in counts or proportions, or another measure suited to the design and endpoint. This is a general description, not a claim about the analysis conducted in this trial. The registry gives no group-specific primary results, effect estimate, or confidence interval, and reports no primary-outcome analyses. Therefore, no comparative estimate can be interpreted from the posted results.
In general, a confidence interval expresses uncertainty around an estimated effect under the assumptions of the analysis. Its width reflects precision: a wider interval indicates greater uncertainty than a narrower interval, all else equal. An interval can also show which values remain compatible with the observed data and method. No such interval is reported for this endpoint, so its precision is not documented in the registry record.
How should significance testing be read?
A hypothesis test evaluates the data against a stated null hypothesis using a statistical model. A p-value is not the probability that the null hypothesis is true, and it does not measure the clinical importance of an effect. Interpretation also depends on the analysis population, outcome definition, model assumptions, and whether the test was planned. These are general principles. The registry record does not report a p-value or a test for the primary outcome, nor does it provide a statistical analysis plan.
The sample-size assumptions described for planning illustrations include a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and effects expressed as a stated fraction of the observed effect. These are planning assumptions, not evidence that the trial was designed using those assumptions. The record does not report a trial-specific sample-size justification. Planning sample sizes based on an observed effect are illustrations for future planning; they are not observed power and do not establish the precision of the trial’s findings.
Why can over-dispersion matter?
In general, count outcomes can vary more than a simple statistical model expects. This is called over-dispersion. If it is present and ignored, standard errors and confidence intervals may not reflect the true variability. Models that allow extra variation can be appropriate for some count data, but the choice depends on the outcome and design. The record does not report a model for the pulmonary-vein count, its variance, or whether over-dispersion was assessed. The primary endpoint is also described as a count of veins, while veins are grouped within participants, so both count variability and within-participant dependence may be relevant considerations in a future analysis.
What can the safety summaries establish?
The safety information is descriptive in the registry. For the visually guided ablation group, it reports serious adverse events for participants at risk and a separate count for other adverse events. Descriptive counts can communicate what was recorded, but a comparative safety analysis requires corresponding information for both groups and clarity about event definitions, observation periods, and analysis methods. The registry does not report these elements for a group comparison. The listed serious-event terms and percentages do not by themselves establish comparative risk or causation.
Overall, the available information supports a description of the trial design and follow-up, not a reconstruction of the primary statistical analysis. The record does not provide the data needed to verify a model, assess assumptions, calculate uncertainty, or compare the two arms. Any such analysis would require information beyond the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and reports no analyses. It does not describe a prespecified statistical analysis plan, a hierarchy of endpoints, or procedures for controlling multiplicity. Multiplicity arises when multiple outcomes, time points, subgroup comparisons, or statistical tests are considered; repeated testing can increase the chance of a chance-positive result. This is a general concern, not evidence that such testing occurred in this trial.
The primary endpoint timeframe is 3 Months. The registry does not report additional time points for that endpoint or specify whether other outcomes were considered primary or secondary in a trial analysis. Without an analysis plan and reported results, it is not possible to assess how outcome selection or multiple comparisons were handled.
Follow-up for effectiveness is incomplete relative to the enrolled and treated populations described in the record: 17 of the 19 treated participants returned for remapping. The record states that these returning participants were evaluable for effectiveness and that 46/59 pulmonary veins were assessed. It does not explain why participants did not return, whether missing veins arose among returning participants, or how missing endpoint data were handled. Imputation, sensitivity analyses, and the assumptions used to address missing data are not reported in the registry record.
The record also does not identify the primary analysis population or state whether the primary analysis was intended to include all randomized participants, treated participants, or those with evaluable remapping. Those distinctions can affect interpretation. The participant flow and endpoint population are described, but the analysis strategy for incomplete follow-up is not.
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 |
|---|---|---|---|
| Visually Guided Ablation | 2 | 19 | 10.5% |
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 |
|---|---|
| Visually Guided Ablation | 0 of 19 |
Most frequent serious adverse event terms
| Event term | Organ system | Visually Guided Ablation |
|---|---|---|
| Pericardial effusion | Cardiac disorders | 1 of 19 |
| Groin bleed | Vascular disorders | 1 of 19 |
Serious events with the highest arm-level rate: pericardial effusion (5.3%), groin bleed (5.3%).
For the visually guided ablation group, the registry reports 19 participants at risk for serious adverse events and 2 affected. For other adverse events, it reports 19 at risk and 0 affected. The listed serious adverse event terms are pericardial effusion at 5.3% and groin bleed at 5.3%. These are registry entries; the record does not provide further event-level detail or establish whether the terms account for all serious events.
The safety figures are not a comparison between the randomized groups. Corresponding risk and event counts for the radiofrequency ablation group are not reported in the registry record. The record does not state whether events were considered treatment-related, how events were defined, or the observation period used for the safety summaries. It also does not report a death count.
In general, adverse-event counts describe what was recorded under a study’s definitions and follow-up procedures. They do not, on their own, show that an intervention caused an event or quantify relative safety. The available entries therefore support only a limited description of reported events in the visually guided group.
12. What the Result Does, and Does Not, Mean
The registry record identifies a randomized comparison of endoscopically guided ablation and electroanatomical-mapping-guided radiofrequency ablation, with chronic pulmonary vein isolation assessed by remapping at 3 Months. It also describes participant follow-up and lists limited safety information for the visually guided group. These details clarify the intended clinical question and the measurement used.
However, the record does not report the primary endpoint values by group, an effect estimate, a confidence interval, or a statistical test. It therefore does not show which group had more pulmonary veins remaining isolated, how large any difference was, or how precisely that difference was estimated. No conclusion about equivalence or superiority follows from the absence of a reported comparison.
The safety entries likewise do not establish comparative safety because corresponding radiofrequency-group figures are not reported. The listed adverse-event terms and percentages should be read as descriptive information rather than as evidence of cause or relative risk.
In general, a trial’s result is interpreted in light of its design, outcome definition, completeness of follow-up, analysis methods, and uncertainty. Here, the registry describes the endpoint and the number of participants who returned, but does not explain the analysis of missing follow-up or the method used for the pulmonary-vein-level outcome. These omissions limit statistical interpretation.
The trial’s terminated status is recorded, but no reason is given. It cannot be used to infer why the trial ended or what effect that had on the evidence. The registry record supports understanding what the study set out to compare; it does not report enough outcome analysis to resolve that comparison.
13. Why This Trial Matters Statistically
This trial illustrates why the unit of analysis should be read alongside the clinical question. Participants were randomized to ablation approaches, while the primary endpoint counts pulmonary veins that remained isolated. The registry reports participant follow-up as well as the number of veins assessed. Those are related but different levels of observation, and an analysis should make clear how they are connected.
It also shows the distinction between an endpoint definition and an endpoint result. The registry gives a specific remapping timeframe and describes what counts as persistent isolation, but does not report the group-specific counts. A detailed outcome definition cannot substitute for an effect estimate or its uncertainty.
The safety record offers another statistical lesson: events reported in one group do not establish a comparative safety profile. A randomized design creates the basis for a comparison, but interpretation still depends on complete group-specific results and transparent methods. In this record, the safety information is limited to the visually guided ablation group.
Finally, the stated effectiveness population makes follow-up important to interpretation. The registry reports that some treated participants did not return for remapping, but does not report reasons or missing-data methods. Such information matters because incomplete assessment can affect how representative the observed endpoint is of the randomized groups.
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 main limitation for interpreting this specific trial record is that no primary endpoint result or between-group analysis is reported. The number of pulmonary veins remaining isolated in each group, a comparative estimate, and its uncertainty are absent. The registry lists no analyses for the primary outcome.
The primary measure is described as a count of treated pulmonary veins, while treatment allocation is at the participant level. The record does not state how the analysis handled veins grouped within participants. It also does not give group-specific endpoint denominators or explain how the 46/59 assessed veins were distributed across participants and treatment groups.
The record says 17 treated participants returned for 3 month remapping, but it does not report reasons for non-return, missing-data handling, or sensitivity analyses. It does not identify the primary analysis population or describe adherence-related analysis decisions. These gaps prevent assessment of how incomplete follow-up may affect the endpoint comparison.
Safety reporting is limited to the visually guided ablation group. Comparative safety cannot be assessed from the listed counts because corresponding radiofrequency-group figures and details about event definitions, attribution, and observation are not reported in the registry record. The record also does not give a reason for trial termination.
Finally, the registry does not report a statistical analysis plan, a trial-specific sample-size justification, or methods for multiplicity. The planning assumptions described for sample-size illustrations do not establish the design rationale or analysis actually used. These limitations concern what can be interpreted from the registry record; they do not establish what information may exist elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Post-Market Randomized Trial: Endoscopically- Guided Ablation vs. Radiofrequency Ablation — NCT01057394.
- Registry record last updated 2016-08-01; status last verified 2016-07.
- Results first posted 2016-08-01.
- 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
NCT01057394 is a Phase 4, randomized, parallel-group post-market trial with no masking, sponsored by CardioFocus. It compares visually guided endoscopic pulmonary vein isolation with radiofrequency pulmonary vein isolation guided by electroanatomical mapping. The record lists the start as 2009-12, primary completion as 2011-06, and status as terminated.
The primary endpoint is described as the number of initially isolated pulmonary veins remaining isolated at 3 month remapping. The record reports 21 enrolled participants, 19 treated participants, and 17 returning for effectiveness evaluation; 46/59 pulmonary veins were assessed. It does not report the endpoint result or a between-group analysis.
Safety figures are listed for the visually guided group only. No primary-outcome analyses are reported, and the record does not explain the termination or provide a statistical analysis plan.