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 The Effect of Blended Sensor Efficiency on Relieving the Heart's Inability to Increase Its Rate During Exercise (NCT01619800), a randomized na study. The primary outcome is Changed in Stress Test at 6 Months as Compared to Baseline.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01619800 |
| Phase | NA |
| Condition | Chronotropic Incompetence |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 2 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Vivek Reddy |
| Results posted | Yes |
2. Clinical Question
Population
The trial concerns patients with chronotropic incompetence: the registry describes this as an inability of the heart to increase its rate in response to increased physical activity or demand. The enrollment recorded was 2. Further eligibility criteria and participant characteristics are not reported in the registry record.
Intervention
The intervention was Blended Sensor Optimization (BSO), a device-based pacemaker setting. The arm description says participants would undergo pacemaker placement, with blended sensor optimization and the Minute Ventilation sensor activated. The brief summary describes the blended sensor as responding to physical activity, heart rate, and breathing rate.
Comparator
The comparator was Accelerometer Alone (AA). Its arm description says participants would undergo pacemaker implantation with the Minute Ventilation sensor not activated and only the accelerometer active. The brief summary characterizes this sensor as using physical activity and heart rate. The record says one pacemaker family would be used.
Primary question
The primary question was whether the stress-test measure changed from baseline to 6 months under the two sensor approaches. The listed outcome is titled “Changed in Stress Test at 6 Months as Compared to Baseline,” with an exercise or “Dobumatime” stress test described. The exact measured variable and a numerical comparison are not reported in the registry record.
3. Trial Design
The registry classifies the study as randomized, single-masked, and parallel, with phase listed as NA. The two named device arms were Blended Sensor Optimization (BSO) and Accelerometer Alone (AA). The arm descriptions distinguish whether the Minute Ventilation sensor was activated: it was to be optimized or activated in BSO and left inactive in AA, with the accelerometer remaining active in AA. The brief summary says the study would use one pacemaker family and compare the blended sensor with an accelerometer-only configuration.
The recorded enrollment was 2. The study status is terminated. Its recorded start is 2012-03, and its primary completion date is 2013-10. The reason for termination, the timing of termination, and whether the planned allocation and follow-up were completed are not reported in the registry record. The identity of the person or group masked is also not reported, so “single-masked” cannot be interpreted more specifically from this record.
The primary outcome was intended to assess a stress test at baseline and 6 months. The registry gives no participant flow, group-level baseline characteristics, or account of how many participants completed the stress test. Although an outcome is listed, no analysis is reported. The adverse-event record lists 2 participants at risk in BSO and 0 in AA; those safety counts do not establish how participants were assigned or followed for the primary outcome. Details of randomization procedures, allocation concealment, and the operational protocol are 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.
Overall Study
| Stage | Blended Sensor Optimization (BSO) | Accelerometer Alone (AA) |
|---|---|---|
| STARTED | 2 | 0 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 2 | 0 |
Reasons for not completing this period:
| Reason | Blended Sensor Optimization (BSO) | Accelerometer Alone (AA) |
|---|---|---|
| study terminated | 2 | 0 |
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 | Blended Sensor Optimization (BSO) | Accelerometer Alone (AA) | Total |
|---|---|---|---|---|
| Participants analysed | 2 | 0 | 2 | |
| Age, Categorical: <=18 years | Participants | 0 | — | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 1 | — | 1 |
| Age, Categorical: >=65 years | Participants | 1 | — | 1 |
| Sex: Female, Male: Female | Participants | 2 | — | 2 |
| Sex: Female, Male: Male | Participants | 0 | — | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Changed in Stress Test at 6 Months as Compared to Baseline, measured over baseline and 6 months.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is titled “Changed in Stress Test at 6 Months as Compared to Baseline.” Its stated timeframe is baseline and 6 months, and its description says an exercise or “Dobumatime” stress test would be performed to assess the outcome. The record does not specify the particular stress-test variable, its unit, the summary parameter, or the way change was to be calculated. It also does not provide numerical outcome results.
In general, a baseline-to-follow-up endpoint is used to describe how a measured characteristic changes over time. Comparing change between randomized groups can address whether the groups followed different patterns under their assigned strategies, subject to the quality of measurement and analysis. A stress test is relevant to the trial’s stated question because the condition and device settings concern heart-rate response to activity or demand. That rationale is general; the registry does not give a detailed endpoint rationale, measurement protocol, or a specific physiological value to be analyzed.
The registry’s skip note says the primary outcome had several categories or time points and was not reduced to one comparison. Consequently, the record does not identify one interpretable effect estimate, nor does it give the direction or magnitude of any change. The outcome’s exact scoring, handling of repeated measurements, and definition of a clinically meaningful difference are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record establishes that a randomized, single-masked, parallel comparison was planned between blended sensor optimization and accelerometer-only pacing. It also establishes an enrollment of 2 and a terminated status. These registry entries describe the trial’s design and scale, but they do not establish what happened to the primary stress-test outcome. No numerical endpoint results or primary analysis are reported in the registry record, and the record lists 0 analyses.
The listed primary outcome concerns stress testing at baseline and 6 months. However, its unit, parameter, and dispersion are absent, and the registry indicates that the outcome involved several categories or time points that were not reduced to one comparison. Without the underlying results and a clearly defined contrast, it is not possible to describe the size, direction, or precision of an effect. In particular, there is no reported confidence interval or hypothesis-test result to interpret.
The enrollment of 2 is important context for reading the record. It indicates a very small recorded study, but it should not be used to infer which arm each participant entered, whether follow-up was complete, or why the trial stopped. Those details are not reported. The safety record lists 2 at risk in BSO and 0 at risk in AA. This is not an outcome comparison: the registry does not show a corresponding AA population at risk, and the primary analysis is absent.
The termination status also limits interpretation. The reason for termination and whether it was related to recruitment, logistics, safety, or another issue are not reported in the registry record. No explanation should be inferred from status alone. The record does not establish that the planned study objectives were met, nor does the absence of a reported result demonstrate that the strategies had identical outcomes.
The appropriate statistical reading is therefore descriptive and cautious: the registry records a small, terminated randomized device trial and identifies a planned stress-test endpoint, but it does not report an analyzable treatment comparison. The available information cannot quantify an effect or its uncertainty, support a claim of benefit or lack of benefit, or establish comparative safety.
9. Statistical Methods Explained
The design labels indicate the intended framework, not a complete statistical analysis plan. Randomization means that assignment was intended to use a chance-based process; the specific sequence-generation and allocation-concealment procedures are not reported in the registry record. A parallel design means the listed arms represent separate assigned groups rather than a stated crossover. Single masking is recorded, but the masked party or parties and the masking procedure are not reported.
What would a between-group comparison estimate?
In general, a randomized comparison estimates differences between groups as assigned, provided the analysis and follow-up preserve the intended comparison. For a baseline-to-follow-up endpoint, an analysis might compare follow-up values, changes from baseline, or a model that accounts for baseline values. These approaches can estimate different quantities and require a defined endpoint and analysis plan. The registry does not report which approach was planned or used. It does not identify the exact stress-test measurement, the outcome scale, or a single contrast between BSO and AA.
What do uncertainty measures convey?
In general, a confidence interval describes the range of effect values that are reasonably compatible with the data and the statistical model used. Its width reflects precision: less information or more variability generally produces less precise estimates. A confidence interval would not, by itself, resolve concerns about bias, missing outcomes, or an unsuitable model. No confidence interval or variance estimate for the primary endpoint is reported in the registry record, so its precision cannot be assessed.
Why does the outcome definition matter?
A clear outcome definition specifies what is measured, how it is scored, when it is measured, and how the comparison is formed. These details are necessary to interpret an estimate and to distinguish a clinically meaningful quantity from a generic change. The registry identifies baseline and 6 months and refers to an exercise or “Dobumatime” stress test, but does not report the variable, unit, parameter, or dispersion. It also notes several categories or time points without reducing them to a single comparison. The intended endpoint analysis therefore cannot be reconstructed from the record.
What can be said about sample-size planning?
The registry includes generic assumptions for planning illustrations: a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect to detect defined as a stated fraction of the observed effect. It also describes how planning quantities are expressed for time-to-event outcomes versus other outcomes. These assumptions do not give a trial-specific sample-size justification, and numerical planning results are not reported in the registry record. The record does not state the original target enrollment or the assumptions used to design this trial. A planning illustration is not an observed power calculation, and it cannot substitute for the missing endpoint estimate and its uncertainty.
What role would a significance test play?
In general, a significance test evaluates how compatible the observed data are with a specified null model, under the test’s assumptions. A p-value is not the probability that a treatment effect is true, nor does it describe the size or importance of an effect. Interpretation normally considers the estimate, its uncertainty, the study design, and the prespecified analysis together. No p-value or test result is reported for the primary outcome. The record also does not state which test or model was planned.
Why can small studies be difficult to interpret?
In general, limited information can make estimates unstable and uncertainty wide, while a small number of participants may make distributional assumptions hard to assess. These are statistical considerations, not a reconstruction of this trial’s results. The recorded enrollment was 2, and the endpoint analysis is absent, so no estimate of variability or model performance is available. Over-dispersion, which means variation greater than a model expects, can matter for some count outcomes; it cannot be evaluated for the stress-test endpoint from this record because no outcome distribution or analysis is reported.
10. Multiplicity, Missing Data and Analysis Populations
The registry notes that the primary outcome had several categories or time points and was not reduced to one comparison. When a study examines multiple outcomes, time points, categories, or contrasts, the chance of observing an apparently notable result can increase if many tests are considered. In general, a prespecified primary contrast and an appropriate multiplicity strategy can clarify which result is confirmatory and how to interpret its uncertainty. The registry record does not report a multiplicity plan, a hierarchy of outcomes, or which categories or time points were intended to be emphasized.
The primary endpoint is described as a comparison involving baseline and 6 months, but its exact measurement and analysis are not specified. No primary outcome analysis or numerical result is reported. The record does not identify whether all planned tests were conducted, whether any were selected for reporting, or whether an adjustment for multiple comparisons was used. These points cannot be inferred from the listed outcome alone.
Missing-data methods and the amount or pattern of missing primary outcome data are not reported in the registry record. There is no account of participants who did not complete follow-up, reasons for missing measurements, or sensitivity analyses. The analysis population is also not specified: the record does not say whether analyses were to follow randomized assignment, include only participants receiving a device setting, or use another population definition. No interim-analysis plan, stopping boundary, or related statistical procedure is reported. The terminated status does not establish that an interim analysis occurred or explain why the study stopped.
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 |
|---|---|---|---|
| Blended Sensor Optimization (BSO) | 0 | 2 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Blended Sensor Optimization (BSO) | 0 of 2 |
| Accelerometer Alone (AA) | 0 of 0 |
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 |
|---|---|
| Blended Sensor Optimization (BSO) | 0 of 2 |
| Accelerometer Alone (AA) | 0 of 0 |
The adverse-event record lists BSO with 2 participants at risk, 0 serious events, 0 other events, and 0 deaths. For AA, it lists 0 participants at risk, 0 serious events, 0 other events, and 0 deaths. No serious-event terms are listed. These figures describe the registry’s reported safety counts; they are not a balanced comparison between the arms.
In particular, zero events alongside 0 participants at risk in AA does not provide evidence about the event experience of an AA participant. The record does not explain why no participants are listed at risk in that group or how the safety population was defined. For BSO, the record reports no affected participants among 2 at risk, but such a small count cannot establish that serious or other events would not occur in a larger or differently followed group.
In general, adverse-event counts should be read with their population at risk, follow-up period, event definitions, and ascertainment procedures. Those additional details are not reported in the registry record. The counts should not be interpreted as proof of safety or as a comparative safety estimate.
12. What the Result Does, and Does Not, Mean
The registry supports a limited description of the intended study: it compared blended sensor optimization with accelerometer-only pacing in patients with chronotropic incompetence, using a randomized, single-masked, parallel design. The listed primary question concerned a stress-test change from baseline to 6 months. The recorded enrollment was 2, and the study status is terminated.
Those details do not provide an answer to the comparative efficacy question. No primary outcome values, effect estimate, confidence interval, or test result are reported in the registry record. The endpoint is not specified sufficiently to reconstruct a statistical comparison, and the record explicitly notes that its categories or time points were not reduced to one comparison. The missing analysis means neither the direction nor the magnitude of a difference can be described.
The absence of a reported result is not evidence that the two sensor strategies produced equal outcomes. It is also not evidence that one strategy performed better. A conclusion about either possibility would require outcome data and a defined analysis. Similarly, the adverse-event counts do not establish comparative safety because the record lists no participants at risk in AA.
The trial’s termination should be kept distinct from its outcome. The reason for termination is not reported, and the status alone does not reveal whether it was related to recruitment, conduct, safety, or another cause. The record cannot establish whether the intended follow-up was completed or whether the available participants represent the planned study population.
In general, a clinical trial’s evidential value depends on the quality and completeness of its design, measurement, analysis, and reporting. Here the registry documents the study question and some design features, but not a usable primary result. The most defensible interpretation is that the posted information is insufficient to estimate the effect of the two device settings or determine how precisely any difference was measured.
13. Why This Trial Matters Statistically
This trial is statistically noteworthy because it illustrates the distinction between a registered comparison and an interpretable treatment-effect estimate. The record specifies randomized assignment and two device strategies, but an analysis is not reported. Without an estimate and its uncertainty, readers cannot quantify the primary comparison or judge its precision.
The enrollment of 2 makes transparent reporting especially important. In general, sparse data can leave estimates highly uncertain and make it difficult to assess whether a model is appropriate. The record does not provide a sample-size justification or a numerical planning target. Its generic planning assumptions do not explain why this study enrolled the recorded number of participants, and they cannot be treated as evidence of adequate power.
The endpoint description also matters. A baseline-to-6-month stress-test comparison could be interpreted in different ways depending on the measured variable, scoring, and analysis. Because these details are not reported and several categories or time points were not reduced to one comparison, the endpoint cannot be translated into a single statistical estimand from the registry record.
Finally, the safety population counts differ across the arms, with 2 at risk in BSO and 0 in AA. That reporting pattern reinforces why denominators and analysis populations must accompany event counts. Overall, this record is a useful example of why registration details alone do not replace outcome reporting, transparent analysis methods, and participant-flow information.
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.
Several limitations specific to this trial constrain interpretation. The recorded enrollment was 2, and the study status is terminated. The reason for termination, the planned target enrollment, the number assigned to each arm, and participant flow are not reported in the registry record. The safety record lists 2 at risk in BSO and 0 in AA, but it does not explain this imbalance or establish the primary-outcome analysis populations.
The primary outcome is identified by a title and a general stress-test description, but its measured variable, unit, parameter, and dispersion are absent. The registry notes several categories or time points without reducing them to one comparison, and no primary analysis is reported. As a result, neither the endpoint estimand nor its precision can be evaluated. Details on missing outcomes, adherence, protocol deviations, and handling of incomplete follow-up are also not reported.
Although the design is labeled randomized, single-masked, and parallel, the sequence-generation method, allocation concealment, and identity of the masked party are not described. The record does not provide a statistical analysis plan, multiplicity approach, interim-analysis information, or analysis-population definition. It also does not report a trial-specific sample-size justification or numerical planning result.
The adverse-event counts are limited by the absence of participants at risk in AA and by the small BSO safety population. Definitions, observation periods, and ascertainment methods are not reported. These omissions, together with the lack of primary outcome results, mean that neither comparative effectiveness nor comparative safety can be assessed from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: The Effect of Blended Sensor Efficiency on Relieving the Heart's Inability to Increase Its Rate During Exercise — NCT01619800.
- Registry record last updated 2017-04-18; status last verified 2017-04.
- Results first posted 2015-03-02.
- 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
The registry record describes NCT01619800, titled “The Effect of Blended Sensor Efficiency on Relieving the Heart's Inability to Increase Its Rate During Exercise,” with the official title “The impAct of Blended Sensor Optimization on resoLVing Chronotropic Incompetence: ABSOLVE CI.” The listed condition is chronotropic incompetence. The study was randomized, single-masked, and parallel, with phase listed as NA.
The two device arms were Blended Sensor Optimization and Accelerometer Alone. The primary outcome concerned stress-test change from baseline to 6 months. Recorded enrollment was 2; the study status is terminated. Its recorded start is 2012-03 and primary completion is 2013-10.
No primary analysis or numerical outcome result is reported in the registry record. The reason for termination, primary analysis methods, and detailed participant flow are not reported. The adverse-event record lists 2 at risk in BSO and 0 in AA, with no serious events, other events, or deaths recorded.