ProMRI Study of the Entovis Pacemaker System: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for ProMRI Study of the Entovis Pacemaker System (NCT01761162), a registered phase not stated study. The primary outcome is MRI and Pacing System Related Serious Adverse Device Effect (SADE) Free Rate.

2. Clinical Question

In plain terms, the question is whether serious device effects related to both the MRI and the pacing system were observed during the stated follow-up period. This is a safety question, not a comparison of the system against another device or treatment. Without a reported endpoint estimate, the size and precision of the measured free rate cannot be evaluated from the registry record.

The study objective was to demonstrate clinical safety under specific MRI conditions. That objective does not, by itself, establish what result was observed or how the evidence was assessed. The registry record gives no numerical primary endpoint result, no confidence interval, and no analysis details. It also does not report the specific MRI conditions or define further eligibility criteria. Those omissions limit how closely readers can match the study population and setting to any particular clinical situation.

3. Trial Design

The ProMRI Study of the Entovis Pacemaker System is recorded as completed. The listed enrollment is 229. The study start is recorded as 2013-02, and primary completion as 2014-03. Biotronik, Inc. is identified as the sponsor. The stated objective was to demonstrate clinical safety of the ProMRI Pacemaker System when used under specific MRI conditions.

The registry describes one arm, Pacemaker Therapy, with the description “Patients with a ProMRI Pacemaker System.” It also lists a Magnetic Resonance Imaging (MRI) scan as an intervention. The record does not describe a separate control arm or a randomized allocation. The allocation method is not stated, and the record cautions that the arms are not a like-for-like control comparison. Consequently, the design information does not support interpreting the study as a randomized comparison of treatment groups.

The primary endpoint is a percentage of participants, with a 95% Confidence Interval listed as its dispersion measure and 1 Month Post-MRI as its timeframe. The record lists five outcome measures, but the primary endpoint’s numerical result is not reported in the registry record. The record also lists zero analyses. This means registry analysis results are not available there; it does not establish whether analyses were performed outside the registry.

Further design information—including detailed eligibility criteria, the MRI protocol, the precise enrollment and analysis populations, and the sample-size justification—is not reported in the registry record. The listed enrollment describes the number enrolled, not necessarily the number included in every outcome analysis. Readers should distinguish the completed study status and enrollment figure from the missing outcome results and analysis details.

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:

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.

6. Primary Endpoint

The registry lists the primary outcome as MRI and Pacing System Related Serious Adverse Device Effect (SADE) Free Rate, measured over 1 Month Post-MRI.

The primary endpoint is the “MRI and Pacing System Related Serious Adverse Device Effect (SADE) Free Rate.” It is expressed as a percentage of participants, with the assessment timeframe listed as 1 Month Post-MRI. In concept, a free rate describes the proportion of participants who did not experience the specified event during the defined assessment period. The event named is a serious adverse device effect related to both the MRI and the pacing system.

General statistical context: a safety endpoint of this kind can describe how often a specified serious event was absent or present in a defined group over a specified period. It is important that the event definition and assessment period are clear, because changing either can change what the endpoint represents. The registry record identifies the endpoint and timeframe, but the endpoint description supplies no further operational definition, and additional detail is not reported in the registry record.

A 95% Confidence Interval is listed as the measure of uncertainty for the endpoint. General statistical context: a confidence interval expresses the precision of an estimate under the assumptions of the method used. A narrower interval indicates greater precision than a wider interval, while neither the estimate nor its interval alone establishes causation or proves that an event cannot occur.

The endpoint’s numerical estimate and confidence interval are not reported in the registry record. Therefore, the recorded endpoint name describes what the study intended to measure, but it does not reveal the observed free rate or its precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary endpoint as a percentage of participants and lists a 95% Confidence Interval. It does not report the endpoint estimate or the interval itself. The statistical methods used to calculate the endpoint are not reported in the registry record. The explanations below describe general statistical concepts relevant to an endpoint of this type, not confirmed methods used in this study.

What does a percentage endpoint represent?

General: a percentage endpoint expresses the share of a defined participant group meeting a specified condition. For a free-rate endpoint, that condition is absence of the event specified by the endpoint definition during the stated period. The result depends on how the event is defined, how participants are followed, and which participants are included in the analysis. A percentage should therefore be read together with its numerator, denominator, event definition, and timeframe whenever those details are available.

For this study, the registry names the outcome as an MRI and pacing system related serious adverse device effect free rate and gives the timeframe as 1 Month Post-MRI. It does not provide the result or the number of participants included in that endpoint analysis. Although enrollment is 229, the analysis denominator cannot be assumed to equal enrollment. Missing follow-up, exclusions, or other analysis decisions could affect a denominator, but the record does not describe whether any such decisions occurred.

What does a confidence interval add?

General: a confidence interval communicates the precision of an estimate under the assumptions of the statistical procedure. The point estimate is the central reported value; the interval indicates a range of values compatible with the data and method at the stated confidence level. A confidence interval is not a guarantee that the true value lies within its particular endpoints, and it does not by itself resolve questions about bias, event classification, or applicability to other populations.

The registry lists a 95% Confidence Interval as the endpoint’s dispersion measure, but no interval endpoints are reported. Readers therefore cannot assess whether the estimate, if one were available elsewhere, was precise or uncertain. The confidence level alone is not an outcome finding.

What can the adverse-event counts tell us?

General: adverse-event summaries describe recorded events or participants affected according to the reporting categories used. Serious adverse events and other adverse events are distinct categories in the registry. Their counts do not automatically equal the number of events meeting a particular primary endpoint, because an endpoint may require a specific seriousness classification and a specific causal relationship. In this study, the primary endpoint names effects related to both MRI and the pacing system. The adverse-event summary alone does not establish that each listed serious event met those endpoint criteria.

The record gives 21 affected participants for serious adverse events and 30 for other adverse events, each among 229 at risk in the Pacemaker Therapy group. It also lists several serious adverse-event terms with percentages. These entries describe the registry’s adverse-event summary; they do not supply the primary endpoint result. The record does not explain the event coding rules or provide further detail on the relationship between these terms and the device, MRI, or endpoint.

Why does over-dispersion matter in general?

General: over-dispersion occurs when observed variability is greater than a statistical model expects. In count data, for example, a model that assumes a particular level of variability may give uncertainty estimates that are too small if the data are more variable than assumed. Methods that account for over-dispersion can produce more appropriate uncertainty estimates when that feature is present. The registry record does not report an over-dispersion assessment, and the posted endpoint is a percentage rather than a reported count-model result. No claim about whether over-dispersion was relevant to the study can be made from the record.

What do sample-size illustrations mean?

General: a sample-size calculation is a planning exercise based on assumptions about an effect to detect, significance level, power, allocation, and statistical method. It is not a statement of what the trial observed. A calculation based on an observed effect is especially dependent on that effect estimate and should be regarded as an illustration, not a prospective design justification. It is not “observed power.”

The recorded planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect described as a stated fraction of an observed effect. The assumptions also distinguish between total event counts for time-to-event calculations and participants per arm for other calculations. These planning assumptions do not establish that the actual study used equal allocation, had two comparable arms, or was designed with that sample size. The registry does not report the study’s own sample-size justification, and the observed primary endpoint result needed to assess an effect-based illustration is not reported in the registry record.

General: when a study has no like-for-like comparison, a conventional two-group sample-size illustration may not describe its actual design. The record cautions that this is not a randomized comparison and that arms are not a like-for-like control comparison. Its allocation is not stated. Therefore, any hypothetical two-arm planning calculation should be read only according to its explicit assumptions, not as evidence that the study conducted such a comparison or attained a specified power.

Overall, the listed endpoint scale and confidence-interval type identify the intended form of the primary result, but the estimate and analysis procedures are absent from the registry record. Statistical interpretation is consequently constrained: methods can be explained in general, but the actual calculation, uncertainty, and analysis decisions cannot be verified from the 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("Pacemaker Therapy")
n      <- c(229)
events <- c(229)
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  Pacemaker Therapy  229  229  100.0  98.4  100.0  98.4  100.0  98.4  100.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures, but the primary endpoint is the only outcome described in detail in the available record. It lists zero analyses. No multiplicity adjustment, testing hierarchy, or strategy for distinguishing primary from secondary analyses is reported in the registry record. This does not establish whether the study team used such procedures outside the registry; it means the registry entry does not allow readers to assess them.

General statistical context: when several outcomes or statistical tests are examined, the chance of at least one apparently unusual result can increase if each is treated as an independent opportunity for discovery. A prespecified hierarchy or multiplicity adjustment can address some of this concern. Which approach is appropriate depends on the study aims and analysis plan. Without a reported plan and results, the effect of multiple outcomes on interpretation cannot be determined.

The record does not report missing-data counts, follow-up completeness, an imputation method, or sensitivity analyses. It also does not identify the analysis population for the primary endpoint. These details matter because the analyzed group and handling of unavailable observations can affect a participant-level percentage. Enrollment of 229 should not be assumed to be the endpoint denominator.

Further details about exclusions, protocol deviations, and analysis populations are not reported in the registry record. As a result, readers cannot assess whether the reported adverse-event counts and the intended primary endpoint used the same population or whether missing observations could have influenced the endpoint estimate. No primary endpoint result is posted against which to evaluate these issues.

12. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: coronary artery disease (1.3%), syncope/pre-syncope (1.3%), angina (0.9%), arrhythmia (0.9%), arterial stenosis (0.9%).

The registry’s Pacemaker Therapy group lists 229 participants at risk for serious adverse events and 21 affected, and 229 at risk for other adverse events and 30 affected. These are separate adverse-event categories. The record also lists serious adverse-event terms: Coronary Artery Disease and Syncope/Pre-Syncope at 1.3% each; Angina, Arrhythmia, Arterial Stenosis, and Infection at 0.9% each. These are the percentages recorded for the listed terms.

These figures should be read as adverse-event summaries, not as the primary SADE-free rate. The primary endpoint specifically concerns serious adverse device effects related to MRI and the pacing system at 1 Month Post-MRI. The adverse-event terms do not, on their own, show that an event was related to MRI, related to the pacing system, or counted as a primary endpoint event. The registry record does not report the primary endpoint estimate or explain how the listed terms relate to it.

General statistical context: counts, participant counts, and percentages answer different questions and are interpretable only with their definitions and denominators. The record identifies participants at risk and affected, but further information on event classification and analysis is not reported in the registry record. Avoid treating the serious-event count, other-event count, or term percentages as a substitute for the missing primary endpoint result.

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

The study record establishes that the trial was completed, enrolled 229 participants, and aimed to assess clinical safety of the ProMRI Pacemaker System under specific MRI conditions. It identifies a primary endpoint focused on the percentage of participants free from an MRI and pacing system related serious adverse device effect at 1 Month Post-MRI. These registry entries describe the study’s question and recorded design, not the numerical answer to that question.

The registry does not report the primary endpoint percentage or its 95% Confidence Interval. Consequently, the record does not show the observed free rate or the precision of its estimate. The serious and other adverse-event counts and listed serious-event terms provide safety information, but they do not replace the endpoint result or establish which events met its specific definition.

The record also does not describe a randomized comparison or a like-for-like control group. Allocation is not stated. Thus, it does not provide a controlled estimate of how outcomes differed between the ProMRI system and another device or condition. The study objective cannot be treated as a result, and the completed status cannot be interpreted as evidence for or against a particular safety conclusion.

General statistical context: a study result applies most directly to its defined participants, procedures, follow-up, and outcome definition. The specific MRI conditions, detailed participant characteristics, and analysis population are not reported in the registry record. Without those details and the endpoint result, readers cannot determine the scope or precision of any safety estimate from this entry.

The appropriate interpretation is therefore bounded. The registry documents a completed safety study, its enrollment, and its intended primary question, along with adverse-event summaries. It does not provide the primary outcome data needed to quantify the SADE-free rate. It cannot establish a comparative effect, and it should not be used to infer findings for settings or populations not described in the record.

14. Why This Trial Matters Statistically

This study illustrates an important distinction in clinical-trial interpretation: a clearly named research objective is not the same as a reported result. The registry identifies a specific safety question, a participant-level percentage endpoint, and a follow-up timeframe. Yet without the endpoint estimate and its confidence interval, readers cannot judge the magnitude or precision of the primary finding.

The distinction between an endpoint and a broad adverse-event summary is also statistically important. A primary endpoint may require a particular event type, seriousness level, causal relationship, and assessment period. General adverse-event counts and terms may inform safety review, but they should not be assumed to measure the same outcome. Here, the SADE-free endpoint is specifically related to MRI and the pacing system, whereas the registry’s adverse-event summary does not report how each event maps to that definition.

The record also shows why design context matters. Allocation is not stated, and the registry cautions that this is not a randomized comparison with like-for-like control arms. Any comparative interpretation would require a suitable comparator and information on how participants were assigned and analyzed. A study’s safety objective alone cannot supply those missing design features.

Finally, reporting of analysis populations, missing data, outcome definitions, and uncertainty is central to evaluating a percentage endpoint. Those elements help readers distinguish the enrolled group from the analyzed group and understand how much the estimate might vary. Their absence from the registry entry limits independent statistical assessment. The case is a reminder that completion status and enrollment are useful record details, but they do not convey the primary outcome or its statistical reliability.

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.

Several study-specific details needed to interpret the safety question are not reported in the registry record. The specific MRI conditions are not described, despite being central to the stated objective. Eligibility criteria, participant characteristics, the operational definition of the primary endpoint, and the detailed follow-up procedures are also not reported. Without those details, the precise setting and population represented by the study cannot be fully characterized.

The registry lists enrollment of 229 but does not report the number included in the primary endpoint analysis or identify the analysis population. It does not provide the primary endpoint estimate or confidence interval. Missing-data counts, follow-up completeness, exclusions, and sensitivity analyses are not reported. These omissions prevent assessment of how the analyzed group may relate to those enrolled and whether unavailable observations affected the endpoint.

The record lists five outcome measures and zero analyses. It does not report the statistical analysis plan, a multiplicity strategy, or the methods used to calculate the primary endpoint. It also does not report the study’s sample-size justification. Planning assumptions described for sample-size illustrations should not be mistaken for the trial’s design justification or actual allocation scheme.

Finally, allocation is not stated, and the record does not describe a like-for-like control comparison. The adverse-event summary does not establish which events met the primary endpoint’s definition. These limitations are specific to the information recorded for this trial; they do not establish that the missing procedures or analyses were absent from the conduct of the study. They do mean that the registry entry alone cannot support a full statistical evaluation of the primary safety result.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: ProMRI Study of the Entovis Pacemaker System — NCT01761162.
• Registry record last updated 2017-02-09; status last verified 2016-12.
• Results first posted 2014-11-04.
• 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 registry record describes the completed ProMRI Study of the Entovis Pacemaker System, sponsored by Biotronik, Inc. It records enrollment of 229, a study start of 2013-02, and primary completion of 2014-03. The objective was to demonstrate clinical safety when the ProMRI Pacemaker System was used under specific MRI conditions.

The primary endpoint is the percentage of participants free from an MRI and pacing system related serious adverse device effect at 1 Month Post-MRI, with a 95% Confidence Interval listed. The endpoint result and interval are not reported in the registry record. The entry lists five outcome measures and zero analyses.

The Pacemaker Therapy group lists 21 participants affected by serious adverse events and 30 affected by other adverse events, among 229 at risk in each category. The record does not describe a randomized, like-for-like control comparison, and allocation is not stated. Detailed MRI conditions, analysis populations, missing-data handling, statistical methods, and the study’s sample-size justification are not reported in the registry record.