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 Oxytocin Effects on Cardiac Electrophysiology (NCT01780337), a randomized early/phase 1 study. The primary outcome is Change in Electrophysiology Measure of AH Interval.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01780337 |
| Phase | EARLY/Phase 1 |
| Condition | Cardiac Arrhythmia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 12 |
| Arms in the primary outcome | 2 |
| Lead sponsor | William Whang |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned individuals undergoing clinically indicated catheter ablation procedures for paroxysmal atrial fibrillation. The registry lists cardiac arrhythmia as the condition. The completed study enrolled 12 participants, while the endpoint description says that only 3 out of 6 in the Oxytocin group and 2 out of 6 in the Saline group were evaluable for the primary endpoint.
Intervention
Participants assigned to Oxytocin received an intranasal dose of 20 IU oxytocin. Electrophysiologic measurements were scheduled at baseline and at 15 minutes and 30 minutes after administration. The registry describes this as a pilot study of intranasal oxytocin.
Comparator
The comparison group received intranasal saline. The study was randomized, double-blind, and parallel, according to the registry. The posted endpoint results contain summary statistics for both groups, but no two-arm comparison was estimable.
Primary question
The primary outcome was change in the electrophysiology measure of AH interval from baseline to 30 minutes, reported in milliseconds. The study description frames the investigation as estimating effects on cardiac refractoriness. The registry does not report an inferential result establishing whether the groups differed on this outcome.
The registry describes the study as a pilot intended to estimate effect sizes for a larger future study. That purpose is important to the interpretation: the posted endpoint summaries are based on a small evaluable subset, and the record does not provide a statistical comparison of the treatment groups. The clinical question is therefore best read as an exploratory measurement question, not as a definitive test of a treatment effect.
3. Trial Design
The study, titled Oxytocin Effects on Cardiac Electrophysiology, is registered as an early phase 1 trial and is marked completed. It used randomized allocation, double masking, and a parallel-group model. The registry lists Oxytocin and Saline as the two interventions. Participants were individuals undergoing clinically indicated catheter ablation procedures for paroxysmal atrial fibrillation.
The Oxytocin group was to receive an intranasal dose of 20 IU oxytocin; the Saline group was to receive intranasal saline. Electrophysiologic measurements were planned at baseline and at 15 minutes and 30 minutes after administration of the study medication or placebo. The primary endpoint uses the measurement at baseline and 30 minutes. The registry describes the measurements as occurring during the pre-ablation period, before general anesthesia and delivery of ablation lesions, while standard ablation procedures continued during the waiting periods.
The registry reports enrollment of 12. Its brief summary says the investigators sought to enroll 20 patients, with the stated purpose of estimating effect sizes for a larger future study. These are different quantities: the first is the recorded enrollment, and the second is the stated target in the study description. The primary endpoint description reports 6 participants in each group as the group counts, but only 3 Oxytocin participants and 2 Saline participants were evaluable for that endpoint.
The study started in 2013-01 and had primary completion in 2016-05. The sponsor is listed as William Whang. The registry record does not report further detail about sequence generation, concealment procedures, masking checks, or a statistical analysis plan. Those design features should not be inferred from the labels randomized and double-blind alone.
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
| Stage | Oxytocin | Saline |
|---|---|---|
| STARTED | 6 | 6 |
| COMPLETED | 6 | 6 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Only 3 out of 6 were evaluable for the Oxytocin group. Only 2 out of 6 were evaluable for the Saline group.
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 | Oxytocin | Saline | Total |
|---|---|---|---|---|
| Participants analysed | 6 | 6 | 12 | |
| Age, Continuous | years | 63.8 (SD 15.5) | 68.1 (SD 3.7) | 66.0 (SD 11.0) |
| Sex: Female, Male: Female | Participants | 1 | 1 | 2 |
| Sex: Female, Male: Male | Participants | 5 | 5 | 10 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Electrophysiology Measure of AH Interval, measured over Baseline and 30 min.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | milliseconds |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is titled Change in Electrophysiology Measure of AH Interval. It is a continuous measure, expressed in milliseconds, summarized as a mean with a standard deviation. The endpoint compares the measurement at baseline with the measurement at 30 minutes after administration. The registry also describes measurements at 15 minutes, but the posted primary endpoint is specifically framed around baseline and 30 minutes.
The study description identifies the broader purpose as assessing measures of cardiac refractoriness in people undergoing a clinically indicated catheter ablation procedure. Within that context, the AH interval was selected as an electrophysiologic measurement, and change in the interval was the outcome specified for the primary analysis. The registry does not provide a more detailed rationale for choosing this endpoint over the other outcome measures, nor does it define a clinically important threshold for interpreting a change.
For the Oxytocin group, the posted mean change was 12.7 milliseconds with a standard deviation of 11.2, based on 3 evaluable participants. For the Saline group, the posted mean change was -1.5 milliseconds with a standard deviation of 13.4, based on 2 evaluable participants. These summaries describe the observed endpoint values among evaluable participants; they do not by themselves quantify uncertainty in the between-group contrast. No confidence interval or estimable two-arm comparison is reported.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The endpoint summaries show a mean change of 12.7 milliseconds in the Oxytocin group and -1.5 milliseconds in the Saline group. The corresponding standard deviations are 11.2 and 13.4. Those figures describe the group averages and the spread of individual observations around each average, respectively. They are based on only 3 evaluable Oxytocin participants and 2 evaluable Saline participants.
The small evaluable counts matter for interpretation. A sample mean can vary substantially from one set of participants to another, particularly when it is calculated from very few observations. The standard deviations describe observed variability, but they do not remove uncertainty about the underlying group averages. Without an interval estimate or a valid two-group analysis, the precision of the apparent difference in group summaries cannot be assessed from the posted results.
The record explicitly indicates that values were missing or not estimable for a two-arm comparison of this continuous endpoint. It reports no analyses. Consequently, there is no posted treatment-effect estimate with a confidence interval, no reported significance test, and no basis in the registry record for judging the statistical compatibility of the results with different possible group effects. The group means should not be treated as a formal comparative result.
The registry describes the study as a pilot whose purpose was to estimate effect sizes for a larger future study. Pilot estimates can be useful for planning, but estimates from very small evaluable groups are uncertain and may be strongly influenced by individual observations. The record does not report a sample-size justification or a prespecified threshold for a meaningful effect. It also does not report an analysis plan that would clarify how the endpoint was to be handled if measurements were unavailable.
Enrollment was 12, while the record states that 3 out of 6 Oxytocin participants and 2 out of 6 Saline participants were evaluable for the primary endpoint. The reason the remaining participants were not evaluable is not reported in the registry record. The endpoint summaries therefore apply to the evaluable participants, not necessarily to everyone enrolled or assigned to a group.
These results are descriptive and limited. They do not establish that oxytocin changed the endpoint relative to saline, nor do they establish that the groups were equivalent. A lack of an estimable comparison is not evidence of no effect. The record leaves the uncertainty too substantial for a reliable comparative conclusion, and the posted data do not support a treatment recommendation.
9. Statistical Methods Explained
The primary endpoint is continuous: it is a measured quantity reported in milliseconds. The registry summarizes it with a mean and standard deviation. The mean describes the average observed change among participants with endpoint data. The standard deviation describes how dispersed the participant-level observations are around that mean. Neither statistic alone gives the uncertainty around a comparison between randomized groups.
What a group mean can tell us
A group mean condenses the observed participant values into one summary. It can be useful for describing the center of the measurements, but its interpretation depends on the number of observations and the variability in those observations. Here, the reported means are based on 3 Oxytocin participants and 2 Saline participants. With so few evaluable observations, each participant’s value can have substantial influence on the group summary. The posted mean is not a prediction for every participant and is not itself an estimate of the uncertainty in a treatment contrast.
What the standard deviation describes
The standard deviation is a measure of spread among observed values. It is not the same as a confidence interval, and it does not show the range of all plausible values for the underlying group mean or between-group effect. The reported standard deviations, 11.2 for Oxytocin and 13.4 for Saline, should be read alongside the small evaluable counts. The registry does not report participant-level data, so the distribution of individual values cannot be inspected from the record.
Why a comparative estimate matters
In a randomized two-group study, the central comparative question concerns the difference in outcomes between assigned groups. A formal analysis can estimate that contrast and describe its uncertainty, typically with an interval estimate and, when prespecified, a test. A confidence interval represents a range of effect values compatible with the data and the model assumptions at a stated confidence level. A narrower interval indicates greater precision; a wider interval indicates greater uncertainty. No confidence interval or two-arm estimate is posted for this endpoint, and no test result is reported.
The registry marks the continuous two-arm comparison as having values missing or not estimable. This means the listed arm summaries do not support a reported formal comparison in the record. It would be inappropriate to create an inferential result from the two means and standard deviations alone, particularly given the very small evaluable groups and the absence of an analysis specification. The posted summaries remain descriptive rather than a substitute for the sponsor’s analysis.
Missing outcomes and analysis populations
The endpoint description states that only 3 out of 6 Oxytocin participants and 2 out of 6 Saline participants were evaluable. This establishes that endpoint availability was incomplete, but it does not explain why. Missing measurements can affect an analysis if the reasons for missingness are associated with participant characteristics or outcomes. Statistical approaches to missing data depend on information about the missingness process and on the assumptions specified in an analysis plan. The reasons, methods, and assumptions are not reported in the registry record.
The term analysis population refers to the participants included in a particular analysis, such as all randomized participants or only those with an observed endpoint. The record identifies the endpoint-evaluable counts, but it does not report a prespecified analysis population or explain how participants without endpoint values were handled. It is therefore not possible to determine from the record whether an intention-to-treat analysis, a per-protocol analysis, or another defined approach was planned or performed.
Planning assumptions are not trial results
The registry’s planning illustration is described as using a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. It defines the effect to detect as a stated fraction of the observed effect. These are assumptions for a planning exercise, not evidence about the effect observed in this study. The registry record does not report a sample-size justification for the trial itself. Any planning illustration based on the observed effect should be treated cautiously when that observed effect comes from very few evaluable participants.
A planning sample size answers a hypothetical design question under stated assumptions. It is not an observed study result and is not observed power. The planning assumptions do not resolve the uncertainty in the endpoint comparison, account for unreported reasons for missing outcomes, or demonstrate that a future study would reproduce the pilot estimate. No numerical planning sample sizes are stated in the registry record.
Multiplicity and interpretation
Multiplicity arises when several outcomes, time points, or comparisons are assessed, increasing the chance of apparently notable findings if results are selected after analysis. The record lists 3 outcome measures, but no secondary outcome results are posted and no analyses are reported. It does not state whether multiplicity adjustments were planned. There is therefore no basis for describing the inferential handling of multiple outcomes or time points. These uncertainties reinforce the descriptive interpretation of the posted primary endpoint summaries.
10. Confidence Intervals for Each Arm
No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.
| Arm | Participants | Mean | Standard deviation | 95% CI for the mean |
|---|---|---|---|---|
| Oxytocin | 3 | 12.700 | 11.200 | -15.122 to 40.522 |
| Saline | 2 | -1.500 | 13.400 | -121.894 to 118.894 |
R code and output
arm <- c("Oxytocin", "Saline")
n <- c(3, 2)
m <- c(12.7, -1.5)
sp <- c(11.2, 13.4)
sd <- sp # posted standard deviations
for (i in seq_along(n)) {
se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}
CARM Oxytocin 3 12.700 11.200 -15.122 40.522
CARM Saline 2 -1.500 13.400 -121.894 118.89411. Multiplicity, Missing Data and Analysis Populations
The registry lists 3 outcome measures and reports no posted secondary outcome results. It reports no analyses for the primary endpoint either. The record does not specify whether the 15-minute measurement was treated as a secondary time point, how other outcomes were ranked, or whether adjustments for multiple outcomes or comparisons were planned. Any multiplicity strategy is not reported in the registry record.
For the primary endpoint, 3 out of 6 Oxytocin participants and 2 out of 6 Saline participants were evaluable. Thus the posted endpoint summaries do not include all participants represented by the group counts. The registry does not report why participants were not evaluable, whether measurements were attempted and unavailable, or whether participants left the study before measurement. The cause and timing of missingness are not reported in the registry record.
The record also does not state the intended analysis population or how missing endpoint measurements would be handled. This leaves open whether the planned analysis would have included every randomized participant, only those with observed endpoint data, or another defined group. Different approaches can answer different questions and may rely on different assumptions. Without the prespecified plan and the reasons for missing outcomes, the impact of the incomplete endpoint data cannot be assessed.
The record reports the evaluable counts and arm-level summaries but marks a two-arm comparison as not estimable. It is therefore important to distinguish the available descriptive results from an analysis of all randomized participants. The record does not establish that missingness was random, nor does it support an assumption about why observations were unavailable.
12. 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 |
|---|---|---|---|
| Oxytocin | 0 | 6 | 0.0% |
| Saline | 0 | 6 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Oxytocin | 0 of 6 |
| Saline | 0 of 6 |
The safety record lists 6 participants at risk in each group. For Oxytocin, 0 participants are recorded as affected by a serious adverse event and 0 by another adverse event. The same figures are recorded for Saline: 6 at risk, 0 affected by a serious adverse event, and 0 affected by another adverse event.
These are counts in the registry record, not evidence that an event could not have occurred or that the interventions are free of risk. The study is small, and the primary endpoint has fewer evaluable participants than the group counts reported in the safety record. The safety counts should be interpreted as the recorded event information for this trial, without extending them beyond its participants.
Deaths are not reported in the registry record. No serious adverse event terms are listed. The absence of listed terms should be read in conjunction with the recorded zero counts, rather than as a detailed account of event types or monitoring procedures. The registry does not provide further safety-analysis details, such as event definitions, follow-up duration, or a comparative statistical assessment. The posted counts are descriptive and do not establish a safety difference between groups.
13. What the Result Does, and Does Not, Mean
The posted result for the primary endpoint is a pair of descriptive summaries among participants with evaluable measurements: a mean change of 12.7 milliseconds for Oxytocin and -1.5 milliseconds for Saline, with standard deviations of 11.2 and 13.4, respectively. The summaries are based on 3 and 2 participants. They give a limited account of the observed data, not a precise estimate of the treatment contrast.
The registry does not report an estimable two-arm comparison, a confidence interval, or a significance test. Therefore, the record does not establish that the groups differ, and it does not establish that they are the same. A result that cannot be compared statistically should not be described as a negative finding or as evidence of equivalence. The amount and direction of uncertainty around a group contrast are not quantified in the posted endpoint results.
The study was described as a pilot intended to estimate effect sizes for a larger future study. Such an exploratory purpose can motivate further investigation, but very small evaluable groups make effect estimates unstable. The available summaries do not show whether the pattern would persist in a larger study, and the registry record does not report a sample-size justification for this trial or a threshold defining a meaningful change.
The endpoint itself is a measurement of change in AH interval from baseline to 30 minutes. The record does not provide a clinically important threshold or a more detailed interpretation framework for a change in milliseconds. The broader aim concerns cardiac refractoriness, but these results alone do not establish the clinical consequences of the measured changes.
Overall, the record documents a randomized, double-blind pilot and posts limited endpoint and safety summaries. The small number of evaluable participants, lack of an estimable comparison, and unreported reasons for missing data constrain what can be inferred. These findings should be understood as incomplete descriptive evidence, not as medical guidance or a definitive assessment of treatment effect.
14. Why This Trial Matters Statistically
This trial is statistically informative in part because it illustrates the difference between recording an outcome and obtaining an interpretable comparison. The registry posts means and standard deviations for both groups, yet also indicates that a two-arm comparison was not estimable. Descriptive summaries can show what was recorded among evaluable participants, but they cannot replace an estimate of the between-group effect and its uncertainty.
The gap between the group counts and endpoint-evaluable counts is also central. The record reports 6 participants in each group for the endpoint population description, while only 3 Oxytocin participants and 2 Saline participants were evaluable. A complete interpretation would require information about why those values were unavailable and how missingness was addressed. Without that information, the endpoint results may not represent everyone enrolled or assigned.
The stated pilot purpose makes precision especially relevant. The investigators sought to estimate effect sizes for a larger future study, but estimates based on very few observations are uncertain and may be sensitive to individual measurements. A planning illustration based on an observed pilot effect is not a substitute for a justified design, and it should not be confused with observed power or a confirmed treatment effect.
The record also shows why readers need to separate safety counts from broad safety conclusions. Zero recorded affected participants in each group is a useful description of the posted data, but a small study cannot settle questions beyond those observations. Together, the incomplete endpoint availability, absent comparative analysis, and pilot scope make transparent reporting of uncertainty and analysis populations essential to statistical interpretation.
15. 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 principal limitation is the small number of evaluable observations for the primary endpoint: 3 in the Oxytocin group and 2 in the Saline group. Although the endpoint description gives 6 participants in each group, the record does not explain why the remaining participants were not evaluable. The effect of this incomplete outcome availability cannot be determined from the posted information.
No formal two-arm comparison is reported, and the registry identifies the endpoint values as missing or not estimable for such a comparison. There is no posted confidence interval, test result, or adjusted analysis. The record also does not report an analysis plan, the intended analysis population, a method for handling missing data, or whether any interim analyses were conducted.
The study description states that investigators sought to enroll 20 patients, whereas the recorded enrollment is 12. The registry does not explain the difference. It also does not report a sample-size justification for the study itself, a clinically meaningful effect threshold, or a detailed rationale for the primary endpoint. The planning assumptions described for an illustration should not be mistaken for the trial’s own design justification.
The record lists 3 outcome measures but posts no secondary outcome results and no analyses. The approach to multiple outcomes and time points is not reported. Safety results are limited to event counts, with deaths not reported in the registry record and no serious adverse event terms listed. Additional details about event definitions, follow-up, measurement procedures, and the reasons for missing endpoint data are not reported in the registry record.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Oxytocin Effects on Cardiac Electrophysiology — NCT01780337.
- Registry record last updated 2016-07-21; status last verified 2016-06.
- Results first posted 2016-06-17.
- 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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19. Record Summary
NCT01780337, Oxytocin Effects on Cardiac Electrophysiology, is a completed early phase 1 randomized, double-blind, parallel-group pilot study. It compared intranasal Oxytocin with intranasal Saline among individuals undergoing clinically indicated catheter ablation procedures for paroxysmal atrial fibrillation. The study started in 2013-01 and had primary completion in 2016-05. Recorded enrollment was 12; the study description says investigators sought to enroll 20 patients to estimate effect sizes for a larger future study.
The primary endpoint was change in AH interval from baseline to 30 minutes, measured in milliseconds and summarized as a mean with standard deviation. Only 3 out of 6 Oxytocin participants and 2 out of 6 Saline participants were evaluable. The record posts group summaries but no estimable two-arm comparison or analysis. Safety counts show no affected participants recorded for serious or other adverse events in either group, while deaths are not reported in the registry record.