Physiologic Pacing Registry: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Physiologic Pacing Registry (NCT03719040), a registered phase not stated study. The primary outcome is Physiologic Pacing Implant Success Rate.

2. Clinical Question

3. Trial Design

The Physiologic Pacing Registry is a prospective, observational, multicenter registry sponsored by Abbott Medical Devices. Its stated aim is to broaden understanding of physiologic pacing implant and follow-up workflows, including pacing and sensing measurements. It also examines the clinical utility of creating a three-dimensional electro-anatomical map of cardiac structures before physiologic pacing device implants, as part of clinical sites' routine care.

The registry began on 2018-11-27, reached primary completion on 2021-10-07, and has a completed status. Enrollment is listed as 870. The primary endpoint description states that 849 subjects underwent attempted physiologic pacing lead implants. These figures describe enrollment and attempted implants; the record does not establish that they are interchangeable analysis populations.

The intervention is a physiologic pacing device implant. The primary analysis population is described as people receiving an Abbott pacemaker, defibrillator, or CRT-P/D with any market-released pacing lead during a physiologic pacing procedure. The procedures were conducted according to each clinical site's routine care. The registry record does not specify the number of participating centers, a randomized allocation, or a concurrent control group. It also does not report a protocol-level analysis plan or the sample-size justification.

Three outcome measures are listed, and no analyses are listed in the record. The primary outcome is investigator-reported implant success during the procedure. The record also includes adverse-event counts, but it does not provide a complete statistical analysis of those events. Without a reported outcome count for implant success, the central endpoint cannot be interpreted as a numerical success estimate.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The patient population for this analysis includes subjects underwent implantation of an Abbott pacemaker, defibrillator, or CRT-P/D with any market released pacing lead as part of a physiologic pacing procedure according to the clinical site's routine care.

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: The patient population for this registry was potential subjects undergoing implantation of an Abbott pacemaker, defibrillator, or CRT-P/D with any market released pacing lead as part of a physiologic pacing procedure according to the clinical site's routine care.

6. Primary Endpoint

The registry lists the primary outcome as Physiologic Pacing Implant Success Rate, measured over During procedure.

The primary endpoint is titled Physiologic Pacing Implant Success Rate. It is measured in participants, uses a count of participants, and is assessed during the procedure. The description says that 849 subjects underwent attempted physiologic pacing lead implants and that success was based on an investigator-reported outcome. The registry record does not report how many attempts were judged successful, the resulting rate, or an uncertainty interval.

General statistical context: a procedural success endpoint can describe whether an intended procedure reached a prespecified or recorded procedural outcome. Such an endpoint may be useful for characterizing implementation in the settings where procedures occur. Its interpretation depends on a clear definition of success, consistent assessment, and an identified population of attempts. The registry record does not give a detailed success definition or assessment criteria beyond investigator reporting.

A rate needs both a count of successful outcomes and a defined denominator. The attempted-implant count is reported, but the success count is not. Therefore, the endpoint's name should not be mistaken for a published numerical result. The posted information identifies what the registry intended to measure, not the observed success rate.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General statistical context: A binary endpoint records whether an outcome occurred for a participant, such as whether a procedure was judged successful. A count of participants with the event is not itself a rate. A rate requires a defined group at risk or a stated denominator as well as the event count. In this registry, the primary endpoint is described as an investigator-reported implant success count, and 849 attempted implants are reported. The success count and resulting rate are not reported in the registry record.

What uncertainty would convey: General statistical context: a confidence interval expresses the range of values compatible with an estimate under a stated statistical model and sampling assumptions. Its width conveys precision; it does not remove possible bias from outcome measurement, selection, or incomplete follow-up. No confidence interval for the primary endpoint is reported in the registry record. Without the underlying success count and a reported estimate, readers cannot assess the endpoint's precision.

Why the design matters: General statistical context: observational registries record care as it occurs rather than assigning participants to treatment groups by randomization. This can make registry evidence useful for describing practice and outcomes across participating settings, while limiting causal interpretation. A randomized comparison can balance many measured and unmeasured characteristics on average; an observational record does not achieve that through random allocation. The Physiologic Pacing Registry is described as observational, and its allocation is not stated. No like-for-like control comparison is identified. Therefore, the registry's reported counts should not be interpreted as evidence of a treatment effect relative to a control.

Clustering and site practice: General statistical context: when participants are treated at multiple centers, outcomes from the same center may be more alike than outcomes from different centers because workflows and clinical practices can vary. Analysis methods can account for this clustering when appropriate. The registry is described as multicenter, but the number of centers and any method for accounting for center-level variation are not reported in the registry record. The record's stated interest in site routine care makes consistency of measurement and practice relevant, but it does not report how these were handled analytically.

Event counts and over-dispersion: General statistical context: event-count data can vary more than a simple statistical model expects, a property often called over-dispersion. If an analysis assumes less variation than is actually present, uncertainty may be understated. The primary outcome is described as a participant count, and adverse-event counts are reported, but the registry record does not identify a statistical model for these outcomes. There is therefore no basis for saying whether over-dispersion was assessed or whether a particular count model was used.

Planning assumptions: General statistical context: a sample-size calculation is a planning exercise based on assumptions about the effect to detect, variability, significance level, allocation, and analysis method. It is not a measure of the observed result and must not be interpreted as observed power. Planning assumptions associated with the registry material describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. They describe an illustration, not a stated design justification for this observational registry. No calculated planning sample sizes or observed effect are reported in the registry record, and the registry does not report two randomized arms.

Analysis and reporting: The record lists three outcome measures and zero analyses. It does not report an analysis population for each outcome, a model specification, covariate adjustment, missing-data method, or inferential results for the primary endpoint. The endpoint description identifies investigator reporting as the basis for success assessment, but does not give a more detailed measurement protocol. These omissions mean readers cannot reproduce an endpoint estimate or evaluate the assumptions behind an inferential analysis from the registry record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Physiologic Pacing Registry")
n      <- c(849)
events <- c(768)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Physiologic Pacing Registry  849  768  90.5  88.3  92.4  88.3  92.3  88.3  92.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures, but no analyses are listed in the registry record. It does not identify a hierarchy of outcomes, a family of statistical tests, or a multiplicity adjustment. General statistical context: when several outcomes or hypotheses are tested, the chance of a false-positive finding can increase if each is assessed independently. A prespecified hierarchy or adjustment can address that issue, but the record does not say whether either was planned or used. Since no analyses are reported, there are no posted primary or secondary hypothesis-test results for which multiplicity can be evaluated.

The primary analysis population is described as subjects who underwent implantation of an Abbott pacemaker, defibrillator, or CRT-P/D with any market-released pacing lead during a physiologic pacing procedure according to the site's routine care. The endpoint description reports 849 subjects with attempted implants, while enrollment is 870. The record does not explain the difference, state how many participants were included in the endpoint analysis, or describe exclusions from that analysis. It also does not report a complete analysis-population definition for the adverse-event figures.

Missing-data handling is not reported in the registry record. There is no account of whether endpoint assessments or follow-up information were incomplete, how missing observations were treated, or whether any sensitivity analysis was conducted. The record also does not describe the duration or completeness of follow-up for adverse events. These details matter because a count or rate can be affected by which participants have available outcome information and by the period over which events are observed. No imputation or other missing-data procedure should be inferred from the posted information.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: infection (2.0%), lead migration/dislodgement (1.4%), exacerbation of heart failure (0.9%), atrial fibrillation (0.7%), death (0.5%).

The registry reports 95 serious adverse events and 47 other adverse events among 870 at risk. It also records 23 deaths. These counts are descriptive. The record does not state whether a participant could contribute to more than one event category, whether all events were adjudicated, or how the at-risk period was defined. The counts should not be interpreted as mutually exclusive groups or as a comparison between treatments.

The listed serious-event terms and percentages are infection, 2.0%; lead migration/dislodgement, 1.4%; exacerbation of heart failure, 0.9%; atrial fibrillation, 0.7%; death, 0.5%; and gastrointestinal bleeding, 0.3%. The registry record does not provide additional detail about how these percentages were calculated or whether they represent participants or events. It also does not report confidence intervals for them. The listed term Death and the total death count of 23 are different forms of reporting; the record does not explain their relationship.

General statistical context: adverse-event summaries describe what was recorded in a defined population and observation period. Without a comparator and fuller information about exposure and follow-up, such summaries do not establish that a device or procedure caused an event, nor do they quantify a comparative risk.

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

The registry's primary endpoint asks whether physiologic pacing implants were recorded as successful during the procedure. It reports 849 subjects with attempted implants, but it does not report the success count or success rate. Thus, the central numerical outcome cannot be determined from the registry record. The absence of a reported estimate is not evidence that success was absent or present; it means the posted record does not quantify it.

The registry does report adverse-event counts and a list of serious-event terms with percentages. Those data describe events recorded among the registry population, but the record does not provide the detail needed to interpret them as comparative risks. In particular, no like-for-like control group or randomized allocation is reported, and the record does not explain overlap between event categories or the observation period for these counts.

General statistical context: an observational registry can characterize clinical workflows and describe recorded outcomes in routine practice. It cannot, by design alone, separate the effect of a procedure or device from differences in who received it, how care was delivered, or what else occurred during follow-up. Such interpretation also depends on clear outcome definitions, complete ascertainment, and appropriate adjustment where needed. The registry record does not report enough information to evaluate these issues fully.

These findings should therefore be read as limited descriptive information about a completed registry, not as a controlled test of a device or procedure. The record supports the statement that the registry sought to describe implant workflows and clinical information and that it recorded certain adverse-event figures. It does not support a numerical conclusion about implant success, a causal claim, or a comparison of outcomes between treatments.

14. Why This Trial Matters Statistically

Statistically, this registry is useful to distinguish a study's stated measurement objective from a result that can actually be estimated from its posted record. The record names implant success as the primary endpoint and identifies investigator reporting during the procedure as the measurement basis. It also reports attempted implants. But without the number recorded as successful, neither a success count nor a success rate can be interpreted. That gap illustrates why endpoint definitions and outcome reporting need to be considered together.

The observational, multicenter design is also relevant. The registry was intended to describe workflows and clinical utility in routine care, rather than to assign a treatment and compare it with a randomized control. Such a design can provide descriptive evidence about clinical practice, but the interpretation of counts depends on the population, measurement process, and follow-up. The record does not report several details needed to evaluate those features, including the center count, a detailed endpoint definition, and the analysis methods.

The adverse-event summary demonstrates another statistical distinction: event counts and listed percentages are not equivalent to a controlled estimate of comparative risk. Without a specified comparator, fuller timing information, and clarity about the relationship among event categories, the reported figures remain descriptive. The record also lists outcome measures but no analyses, limiting the available basis for assessing precision or inferential claims.

These limitations are not unique to this registry; they are central considerations when reading observational clinical data. Clear denominators, transparent outcome definitions, complete analysis populations, and uncertainty estimates help readers understand what a reported number represents. In this record, the design and intended questions are described more fully than the primary outcome result.

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 primary limitation for interpreting the main endpoint is that the registry record does not report the success count or rate, even though it names implant success as the primary outcome and reports 849 attempted implants. The endpoint is investigator-reported, but the record does not provide a detailed operational definition, assessment criteria, or information about consistency of assessment across sites. The reported enrollment of 870 and attempted-implant count of 849 are not reconciled, and the endpoint analysis population is not fully specified.

The registry is observational, and no randomized allocation or like-for-like control comparison is reported. This prevents a direct controlled comparison and limits causal interpretation. The record does not report the number of centers, participant characteristics beyond the listed conditions, center-level analytic methods, or potential adjustment variables. It also does not report a detailed statistical analysis plan, model specifications, confidence intervals, or hypothesis tests.

For adverse events, the record gives counts and selected serious-event terms with percentages, but does not describe the event definitions, ascertainment procedures, timing, follow-up duration, or whether categories overlap. The relationship between the 23 deaths and the listed death term is not explained. Missing-data handling and the completeness of follow-up are not reported. These limitations restrict interpretation of both event frequency and uncertainty.

The registry's purpose includes workflow description and the clinical utility of mapping according to site routine care, but the record does not report a numerical result for mapping utility. No detailed sample-size justification for the registry is reported. Planning assumptions associated with an illustration do not substitute for a stated design rationale or an analysis of the registry's observed outcomes.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Physiologic Pacing Registry — NCT03719040.
• Registry record last updated 2024-08-19; status last verified 2024-08.
• Results first posted 2024-08-19.
• 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.

19. Record Summary

The Physiologic Pacing Registry (NCT03719040) is a completed, prospective, observational, multicenter registry sponsored by Abbott Medical Devices. Enrollment is 870. The registry began on 2018-11-27, and primary completion was 2021-10-07. Its stated aims include describing physiologic pacing implant and follow-up workflows and the clinical utility of creating a three-dimensional electro-anatomical map before device implantation as part of routine site care.

The primary endpoint is investigator-reported physiologic pacing implant success during the procedure. The record reports 849 subjects with attempted implants but does not report the number successful or the success rate. It lists three outcome measures and no analyses. Adverse-event reporting includes 95 serious events, 47 other events, and 23 deaths among 870 at risk, with selected serious-event terms and percentages. The record does not report a randomized comparator, a detailed statistical analysis plan, or enough outcome detail for a comparative or causal conclusion.