SJ4 Post Approval Study in Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy Defibrillator Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for SJ4 Post Approval Study in Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy Defibrillator Patients (NCT00940888), a registered phase not stated study. The primary outcome is Right Ventricle (RV) Bipolar Capture Thresholds.

2. Clinical Question

The clinical question is descriptive rather than a randomized comparison of two treatments. The registry identifies the device system under study and an endpoint intended to characterize performance over time. It does not set out a treatment-versus-control contrast or describe a control arm suitable for estimating such a contrast.

The endpoint is defined by a measurement recorded at the five-year follow-up visit. Its stated population therefore consists of participants who had an RV bipolar capture threshold at that visit, not necessarily every participant enrolled. The number of participants contributing to this endpoint is not reported in the registry record.

The registry record does not report the mean threshold, the 90% confidence interval, or other numerical primary outcome results. It consequently does not allow a reader to determine the observed threshold level or its precision from the record alone. The listed conditions are tachyarrhythmias, sudden cardiac death, and heart failure, while the stated study purpose is device-performance characterization.

3. Trial Design

This is the SJ4 Post Approval Study, a completed study identified as “other” in the registry. It enrolled 1701 participants. The recorded start is 2009-06, and the primary completion is 2015-09. The sponsor is Abbott Medical Devices.

The study purpose was to characterize chronic performance of the St. Jude Medical SJ4 connector and RV high voltage SJ4 leads. The intervention is listed as a device: the SJ4 connector and RV high voltage SJ4 lead. The adverse-event group is titled “SJ4 System Implanted.” These descriptions identify the device being followed, but do not establish a randomized comparison or a separate control group.

The registry identifies an arm description, “No treatment: ICD/CRTD-indicated,” but does not state how allocation was determined. The record warns that this is not a randomized comparison and that the arms are not a like-for-like control comparison. In the absence of a suitable comparator, the design should be read as a device-performance study rather than as a controlled estimate of a treatment effect.

Two outcome measures are recorded, but the registry record does not provide an analysis entry for either. The primary outcome is RV bipolar capture thresholds, with a mean as the stated measure, a 90% confidence interval as the stated dispersion, and a five-year timeframe. No protocol details beyond the information in the registry record are available: the sample-size justification, detailed statistical plan, interim analyses, and approach to follow-up 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Study participants with RV bipolar capture threshold at the 5 year follow up visit.

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: Participants had an approved indication, as per ACC/AHA/HRS guidelines, for implantation of an ICD or CRT-D system for treatment of heart failure or life-threatening ventricular tachyarrhythmia(s) and will be implanted with a St. Jude Medical SJ4 system and had given informed consent prior to enrollment.

6. Primary Endpoint

The registry lists the primary outcome as Right Ventricle (RV) Bipolar Capture Thresholds, measured over 5 years.

The primary endpoint is the mean right ventricle (RV) bipolar capture threshold, measured in Volts. The stated timeframe is five years. The endpoint population is participants with an RV bipolar capture threshold recorded at the five-year follow-up visit.

A capture threshold describes the level at which a device stimulus captures the heart tissue in the measured chamber. In general, measuring such a threshold can serve as one indicator of device performance. The registry record’s stated purpose is to characterize chronic performance of the SJ4 connector and RV high voltage SJ4 leads; it does not provide a separate clinical benefit endpoint or explain why this particular endpoint was selected.

The registry specifies a mean and a 90% confidence interval. In general, the mean describes the central level of the recorded measurements, while a confidence interval conveys uncertainty around an estimate under the statistical method used. A confidence interval does not show the spread of individual participants’ measurements; that is a different feature of the data.

The registry record does not report the mean, confidence interval limits, or the number of participants contributing measurements. The endpoint definition therefore indicates what was intended to be summarized, but the numerical result and its precision are not reported in the registry record. The record also does not describe how measurements were handled when a participant missed the five-year visit or had no usable threshold measurement.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a mean RV bipolar capture threshold in Volts, with a 90% confidence interval and a five-year timeframe. It does not report the estimate or interval limits, and it records zero analysis entries. The methods can therefore be described only at the level of the endpoint and general statistical concepts; the analysis procedure used for this study is not reported in the registry record.

What does a mean summarize?

In general, a mean is a measure of the central level of a set of numerical observations. It uses the magnitudes of the observations, so unusually high or low measurements can influence it. For a clinical endpoint, interpreting a mean requires knowing which participants contributed data and how the measurement was collected. The registry specifies participants with a threshold measurement at the five-year follow-up visit, but it does not report the number measured or the distribution of their values.

A mean alone does not describe how much participants’ measurements varied. It also does not indicate whether a result is clinically important. The registry record gives no threshold estimate, variability summary, reference value, or interpretation criterion. Those details cannot be inferred from the choice of a mean as the summary measure.

What does a confidence interval communicate?

In general, a confidence interval expresses uncertainty around an estimated quantity under a specified statistical procedure and its assumptions. A narrower interval indicates greater statistical precision than a wider interval, all else equal. The interval is not a range containing every participant’s measurement, and it is not a guarantee about the value in any individual participant.

The registry names a 90% confidence interval for the primary endpoint. It does not give either limit, say how the interval was calculated, or describe assumptions used to account for the data structure. Without the interval itself, its width and the precision of the estimate cannot be judged. The confidence level alone does not reveal whether the estimate is clinically meaningful or whether the study’s follow-up data represent all enrolled participants.

Why does the endpoint population matter?

The primary endpoint is defined among participants with an RV bipolar capture threshold at the five-year follow-up visit. This is a measurement-based population definition. It should not automatically be treated as equivalent to the full enrolled cohort of 1701. In general, if follow-up measurements are unavailable for some participants, a mean among observed measurements may differ from the mean that would have been obtained if measurements were available for everyone. The direction and extent of any such difference depend on why data are missing and on the values that would otherwise have been observed.

The registry record does not report the number with a five-year measurement, reasons for missing measurements, or any method for addressing missing data. It therefore does not establish whether the endpoint estimate represents all enrolled participants or only those with observed follow-up. The record also does not describe an analysis population apart from the endpoint’s stated eligibility description.

What can be inferred from the study design?

The study is identified as a post-approval study and is intended to characterize chronic device performance. The registry warns that it is not a randomized comparison, that allocation is not stated, and that its arms are not a like-for-like control comparison. In general, random allocation can help make groups comparable with respect to both measured and unmeasured characteristics. Without a randomized, suitable control comparison, differences between groups can reflect differences in who was included, their clinical circumstances, or other factors, as well as any device-related influence.

The design description therefore supports a descriptive reading of measurements collected in the study, not a causal estimate against a comparable control group. The record does not report a comparative estimate for the primary endpoint. It also does not report adjustments for other factors, subgroup analyses, or a prespecified model.

What does the lack of analysis entries mean?

The registry records two outcome measures and zero analysis entries. That means no analysis-specific results are available in the registry record, including estimates or inferential tests attached to those outcomes. It does not establish that no analysis was conducted outside the registry; it establishes that analysis results are not recorded there. Likewise, a detailed statistical analysis plan, interim analyses, and a sample-size justification are not reported in the registry record.

General statistical practice distinguishes the result observed in a study from planning calculations about a future study. A planning calculation can illustrate what sample size might be needed under specified assumptions, but it is not “observed power” and does not replace the reported estimate and its uncertainty. The registry’s record does not give a study-specific sample-size justification. Any planning illustration should not be treated as evidence that the completed study had a particular probability of detecting an effect.

These general principles help explain what the listed endpoint and design would mean statistically. They cannot supply the missing endpoint values or determine the actual procedures used in this study. For those details, the registry record is not informative.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures, but records zero analysis entries. It does not report which outcomes were analyzed, whether any were designated secondary, or whether multiple comparisons were planned. A multiplicity procedure or a rationale for not using one is not reported in the registry record.

In general, when several outcomes or repeated statistical tests are examined, the chance of at least one apparently unusual result can increase if each test is treated as an isolated finding. Prespecified priorities and appropriate multiplicity methods can help clarify how results should be interpreted. The registry information does not establish whether this issue was addressed in the study’s analysis.

The primary endpoint description refers to participants with a threshold measurement at the five-year follow-up visit. The number with such a measurement, the number without one, reasons for missingness, and the method used to handle missing data are not reported in the registry record. In general, missing follow-up data can affect interpretation if the availability of measurements is related to participants’ health, device experience, or measured threshold. The record does not allow the extent or direction of any such effect to be assessed.

The analysis population is not otherwise described. The registry does not state whether all enrolled participants, only participants with observed measurements, or another defined population was used for any analysis. It also does not report interim analyses, a detailed statistical analysis plan, or the sample-size justification. These omissions limit assessment of how outcomes were selected, how incomplete observations were handled, and whether the reported analysis followed a prespecified approach.

11. 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 1% reporting threshold.

Most frequent non-serious adverse event terms

For the “SJ4 System Implanted” group, the registry lists 1701 participants at risk for serious adverse events and 0 serious adverse events affected. For other adverse events, it lists 1701 at risk and 376 affected. The record does not list any top serious adverse-event terms. Deaths are marked as not reported in the registry record.

These counts should be read as the adverse-event figures recorded for this group, not as a complete clinical description. The registry entry does not report event-level details, timing, duration, severity categories beyond the serious-versus-other distinction, or whether events were considered related to the device. It does not provide further information about how events were collected or classified.

In general, an event count and an at-risk count provide context for the recorded safety information, but do not by themselves explain the clinical nature of events or establish causation. The posted counts do not show how many events occurred per participant, whether events were recurrent, or how events were distributed over follow-up. Those details are not reported in the registry record. The listed count of 0 serious adverse events should therefore be reported as the registry figure, without treating it as a complete account of safety or inferring unreported details.

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

The registry record identifies a completed study designed to characterize chronic performance of the SJ4 connector and RV high voltage SJ4 leads. It defines a primary endpoint: the mean RV bipolar capture threshold in Volts at the five-year follow-up among participants with a measurement at that visit. It also records enrollment of 1701 participants and gives adverse-event counts for the SJ4 System Implanted group.

However, the registry record does not report the numerical primary endpoint result or its 90% confidence interval. It therefore does not show the observed mean threshold, the precision of that estimate, or the number contributing to the endpoint. A defined endpoint is not itself an outcome result. Without its estimate and uncertainty, the central measurement cannot be evaluated from this record.

The study is not described as a randomized, like-for-like comparison; allocation is not stated. Consequently, the record does not provide a basis for attributing any difference between groups to the device. It also does not report a comparative analysis. The study purpose and endpoint support a descriptive characterization framework, but the numerical endpoint findings needed for that characterization are absent from the registry record.

The safety counts are limited to the figures listed: 0 serious adverse events and 376 other adverse events among 1701 at risk in the named group. Event details, deaths, and causal assessments are not reported in the registry record. The numbers should not be converted into claims about the full safety profile or interpreted as proving a causal relationship.

In general, study results are interpreted in light of their design, measurement completeness, uncertainty, and analysis choices. Here, the registry record does not report the analysis details or missing-data handling needed to assess these features. The record documents the study and selected outcomes, but does not establish a controlled treatment effect or supply enough endpoint information to judge the observed five-year threshold estimate.

13. Why This Trial Matters Statistically

This study is statistically notable as a post-approval device-performance study with a stated long-term measurement, rather than a randomized comparison. Its purpose is to characterize chronic performance of the SJ4 connector and RV high voltage SJ4 leads. Recognizing the descriptive design helps keep interpretation aligned with what the registry record can support: characterization rather than a controlled causal comparison.

The primary endpoint is a mean measured at the five-year follow-up, with a 90% confidence interval specified as the uncertainty summary. That combination identifies both the target quantity and the intended way of expressing precision. It also highlights why the numerical result matters: the endpoint definition alone cannot indicate the magnitude or precision of the observed measurement. Neither the mean nor the interval is reported in the registry record.

The endpoint’s visit-based population raises a further statistical question about follow-up completeness. In general, a summary of participants with observed measurements may not represent all enrolled participants if measurement availability is selective. The registry record does not give the number with a five-year measurement or explain missing data, so the representativeness of the endpoint population cannot be assessed.

The safety record also illustrates the importance of separating counts from interpretation. The registry lists serious and other adverse-event figures, but does not provide the detailed event descriptions needed to understand their nature, timing, or relationship to the device. Reporting those counts precisely is more informative than extending them into conclusions the record cannot substantiate.

Finally, the record includes two outcome measures but no analysis entries. This leaves a gap between the stated measurement framework and the statistical results needed to interpret it. The study’s design, endpoint, and posted safety counts are identifiable; the primary estimate, its precision, and key analysis details are not reported in the registry record.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The most important limitation of the registry record for interpreting this study is that the primary endpoint result is not reported. Although the outcome is defined as a mean RV bipolar capture threshold in Volts with a 90% confidence interval at five years, neither the mean nor interval limits appear in the record. The number of participants contributing to that outcome is also not reported.

The endpoint applies to participants with a measurement at the five-year follow-up visit. The registry does not report follow-up completeness, reasons for absent measurements, or the handling of missing data. As a result, it is not possible to judge whether the observed endpoint population represents the enrolled cohort or whether missing measurements could affect interpretation.

The design is not a randomized, like-for-like control comparison, and allocation is not stated. The record therefore does not provide a suitable basis for a controlled comparison or causal attribution. It also records zero analysis entries, leaving no analysis-specific estimates, uncertainty results, or inferential comparisons to evaluate.

The registry lists adverse-event counts but does not report details about event types, timing, recurrent events, or causal assessment. Deaths are not reported, and no top serious adverse-event terms are listed. These omissions limit the safety description to the counts recorded.

Additional study details—including the sample-size justification, detailed statistical plan, and interim analyses—are not reported in the registry record. The record also does not explain the rationale for selecting the primary endpoint. These limits concern what can be concluded from the registry information; they do not establish what procedures may have been documented elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: SJ4 Post Approval Study in Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy Defibrillator Patients — NCT00940888.
• Registry record last updated 2019-02-04; status last verified 2019-01.
• Results first posted 2017-08-14.
• 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.

18. Record Summary

The SJ4 Post Approval Study is listed as completed, with enrollment of 1701 participants. Its recorded start is 2009-06 and its primary completion is 2015-09. The sponsor is Abbott Medical Devices. The study purpose is to characterize chronic performance of the SJ4 connector and RV high voltage SJ4 leads.

The primary outcome is the mean RV bipolar capture threshold in Volts at five years, among participants with a measurement at that follow-up visit. A 90% confidence interval is specified, but the estimate and interval limits are not reported in the registry record. Two outcome measures are listed, with zero analysis entries.

The registry identifies no randomized, like-for-like control comparison and does not state allocation. For the SJ4 System Implanted group, it lists 0 serious adverse events and 376 other adverse events among 1701 at risk. Deaths are not reported in the registry record. The available record therefore describes the study framework and selected safety counts, but does not give the primary endpoint result or detailed analysis information.