PEFCATII Expanded Safety and Feasibility Study of the FARAPULSE Endocardial Multi Ablation System to Treat Paroxysmal Atrial Fibrillation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for PEFCATII Expanded Safety and Feasibility Study of the FARAPULSE Endocardial Multi Ablation System to Treat Paroxysmal Atrial Fibrillation (NCT04170608), a na na study. The primary outcome is Safety: Number of Participants With Prespecified Primary Safety Events Within 30 Days of Index Procedure..

2. Clinical Question

PEFCAT II concerns the use of the FARAPULSE Endocardial Multi Ablation System in participants with paroxysmal atrial fibrillation. The registry describes a single-group study, with an enrollment of 10 and no randomized comparator. Its primary question is about safety: how many participants experienced a prespecified primary safety event within 30 days of the index procedure.

This question is descriptive rather than a comparison of outcomes between assigned treatments. The registry also reports counts for serious and other adverse events, but these categories should not be treated as interchangeable with the specifically defined primary safety endpoint. The record does not state whether every listed primary safety event occurred, how events were adjudicated, or whether participants had complete follow-up for the endpoint.

3. Trial Design

PEFCAT II is recorded as a completed, single-group study of the FARAPULSE Endocardial Multi Ablation System. The study concerns paroxysmal atrial fibrillation, and its intervention is described as ablation using that device. Enrollment is listed as 10. The registry gives the start date as 2019-10-18 and the primary completion date as 2020-12-07.

The study has no randomized comparator in the registry record: allocation is listed as NA, and the model is single group. Masking is recorded as NONE. These details mean the posted data describe outcomes among participants treated in the study arm; they do not estimate a randomized contrast between the device and another treatment or a control condition. The absence of masking also means the record does not describe outcome assessment as blinded.

The registry lists the phase as NA. A phase classification, further protocol details, the planned recruitment target, and a sample-size justification are not reported in the registry record. The record does not explain why the study enrolled 10 participants or whether that number was chosen to address feasibility, safety precision, or another objective.

Two outcome measures are recorded, and no analyses are listed in the analysis information. The primary outcome is a participant count for prespecified safety events within 30 days of the index procedure. The record does not provide the numerical primary-outcome result or a detailed statistical analysis plan. It also does not report an interim-analysis plan, a prespecified stopping rule, or a method for handling incomplete follow-up.

Because the design is single-group and the enrolled sample is small, the study is best understood as a descriptive safety and feasibility investigation, not as a controlled estimate of comparative benefit or harm. That characterization follows from the design and endpoint recorded; details of the study's intended decision criteria 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.

Before assignment: A total of 10 patients were enrolled (signed informed consent) and 10 subjects were treated at two (2) sites in Europe.

Overall Study

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 Safety: Number of Participants With Prespecified Primary Safety Events Within 30 Days of Index Procedure., measured over 30 Days.

The primary endpoint is titled as the number of participants with prespecified primary safety events within 30 days of the index procedure. Its unit is participants, and its measure is a count of participants rather than a rate of events. The listed event definition includes death, myocardial infarction, diaphragmatic paralysis, stroke or transient ischemic attack, thromboembolism, pericarditis, tamponade or perforation, vascular access complications, hospitalization, heart block, pulmonary vein stenosis, and atrioesophageal fistula.

A participant-count endpoint is useful for describing how many people experienced one or more events in the defined period. It gives a clinically interpretable summary of safety outcomes, while the specified time window makes clear which follow-up interval the endpoint concerns. A count of participants is different from a count of all event occurrences: a participant with multiple events may still contribute once to a participant-based endpoint, depending on the analysis definition. The registry does not state how recurrent events were handled or whether events were independently adjudicated.

The numerical result for this primary endpoint is not reported in the registry record. The separate adverse-event figures list 0 of 10 participants with serious adverse events, but those figures are not identified as the numerical result for the defined primary endpoint. Without an explicit link in the record, the serious-adverse-event count should not be substituted for the primary-endpoint result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General explanation: the endpoint is a participant count. For a binary outcome, each participant is classified according to whether the specified event occurred during the defined period. The aggregate count can describe the observed study group, but interpretation depends on the endpoint definition, the number of participants with evaluable follow-up, and how missing outcomes are treated. The registry record names the endpoint and its 30-day timeframe but does not report the primary-endpoint result, its missing-data rules, or the analysis population.

What does a participant count capture?

The primary endpoint asks how many participants had prespecified safety events, not how many total event episodes occurred. In general, participant-based endpoints avoid counting one participant multiple times in the headline total when the measure is defined as the number of people affected. However, the registry does not specify whether a participant with more than one listed event was counted once, nor does it provide an event-level listing. The result therefore cannot be reconstructed from the event definitions alone.

The endpoint's list spans a range of outcomes, including death, cardiovascular and neurological events, procedural complications, hospitalization, and other specified complications. Combining varied events into one endpoint can provide a broad safety summary. General explanation: a composite endpoint can be difficult to interpret if its components differ in severity or frequency, because the total does not reveal which components account for the result. The record does not report component-specific primary-endpoint counts, so the contribution of each listed event is unknown.

Why does the design matter?

PEFCAT II is recorded as a single-group study with allocation listed as NA and masking listed as NONE. A single-group design can describe observed outcomes after the intervention, but it does not supply a concurrent randomized control group for estimating a treatment contrast. General explanation: random allocation helps balance both measured and unmeasured characteristics between groups on average. Without such allocation, an outcome count cannot distinguish an intervention-associated effect from background risk, participant characteristics, or other aspects of care.

Masking concerns whether participants, clinicians, or outcome assessors know the assigned intervention. The record specifies NONE, but does not identify which roles were unmasked or explain how outcomes were assessed. General explanation: awareness of treatment can influence reporting, care decisions, or subjective outcome assessment. This concern may be less direct for clearly defined events than for subjective measures, but the record does not provide enough detail to assess event ascertainment.

How should small-sample counts be read?

The enrollment is 10. In a group this small, each participant's classification has a visible effect on the count, and the observed data provide limited information about the range of outcomes that could occur in a larger population. General explanation: a confidence interval around a proportion or event risk expresses sampling uncertainty; it does not address biases caused by selection, incomplete follow-up, or outcome misclassification. No confidence interval or other uncertainty interval is reported for the posted adverse-event counts.

General explanation: over-dispersion matters when observed variability is greater than a model's assumptions allow. For a simple binary participant outcome, the usual binomial model assumes a common event probability and independent participant outcomes. Dependence among participants or meaningful differences in their risks can make that model's uncertainty estimates too narrow. The registry does not report a model-based analysis or information sufficient to evaluate such assumptions. No over-dispersion adjustment is reported.

What statistical results are available?

The registry lists two outcome measures and no analyses. The primary endpoint's measurement definition is a count, but its numerical result is not reported in the registry record. The adverse-event summary reports 0 of 10 with serious adverse events, 6 of 10 with other adverse events, and 0 deaths. No p-value, confidence interval, model estimate, or adjusted result is reported. These counts should be interpreted descriptively, not as evidence from a reported hypothesis test.

The sample-size assumptions recorded for planning illustrations describe hypothetical calculations based on an observed effect, with two-sided significance level 0.05, equal allocation, and a normal approximation. They are not the study's own design rationale and do not represent observed power. Since the study is single-group, a hypothetical two-arm planning illustration cannot change the design or create a comparator that was not present. The sample-size justification for PEFCAT II is not reported in the registry record.

General explanation: statistical power is a design-stage probability of detecting a specified effect under stated assumptions. It is not a measure of whether a completed study's result is true, and a retrospective power calculation does not resolve uncertainty in an observed estimate. The available record does not report a prespecified power target, effect size for design, or formal calculation supporting the enrollment. No study-specific power conclusion can be drawn from the adverse-event counts.

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("FARAPULSE Endocardial Ablation")
n      <- c(10)
events <- c(0)
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  FARAPULSE Endocardial Ablation  10  0  0.0  0.0  30.8  0.0  27.8  0.2  28.5

11. Multiplicity, Missing Data and Analysis Populations

The registry records two outcome measures, but the numerical result for the defined primary safety endpoint is not reported in the registry record. No analyses are listed. The available information does not identify a hierarchy of outcomes, a multiplicity adjustment, or rules for selecting which outcomes to emphasize. Those details are not reported in the registry record.

General explanation: when several outcomes or statistical tests are examined, the chance of at least one apparently unusual result can increase if each test is interpreted without accounting for the others. Prespecified outcome hierarchies or multiplicity adjustments can address that issue. The registry record does not state whether any such approach was planned or used. Because no inferential analyses are listed, there are no reported p-values whose multiplicity handling can be assessed.

The record does not report whether all enrolled participants completed the 30-day follow-up, how missing outcomes were handled, or whether any participants were excluded from an analysis. It also does not describe an intention-to-treat, per-protocol, or safety analysis population. The adverse-event summaries use 10 participants as the number at risk, but that alone does not establish completeness of all endpoint assessments or resolve how missing information was treated.

General explanation: missing outcome data can bias a result if the probability of being observed is related to the outcome. A complete-case count describes only participants with recorded outcomes unless the analysis specifies otherwise. Without follow-up completeness, exclusion rules, or imputation procedures, the direction and size of any missing-data effect cannot be assessed.

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 non-serious adverse event terms

The posted adverse-event figures list 10 participants at risk for serious adverse events, with 0 affected; 10 at risk for other adverse events, with 6 affected; and 0 deaths. These counts describe the registry's adverse-event summaries for the FARAPULSE Endocardial Ablation group. The record does not provide event-level details for the six participants in the other-adverse-event category, and the list of top serious adverse-event terms is empty.

These summaries should not be conflated with the primary safety endpoint. That endpoint is defined by a specified list of events within 30 days of the index procedure, but its numerical result is not reported in the registry record. The registry does not say that the serious-adverse-event category is equivalent to the endpoint's event list, nor does it provide enough information to map each adverse-event summary to each primary-endpoint component.

General explanation: a count of zero observed events does not prove that the true event risk is zero. The result is limited by the number of participants observed, follow-up completeness, and how events were collected and classified. The record does not report confidence intervals, detailed severity or timing information, or event attribution. These counts therefore support a description of recorded events in this study group, not a precise estimate of risk in a wider population or a comparison with another treatment.

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

The results support a limited descriptive statement about the study group: the registry reports 0 of 10 participants with serious adverse events, 6 of 10 with other adverse events, and 0 deaths. PEFCAT II is recorded as a completed single-group study of the FARAPULSE Endocardial Multi Ablation System in participants with paroxysmal atrial fibrillation. These figures characterize the adverse events recorded in that group; they do not establish a comparative treatment effect.

The primary safety endpoint is specifically defined as the number of participants with prespecified events within 30 days of the index procedure. Its numerical result is not reported in the registry record. The adverse-event counts cannot be assumed to be the primary endpoint result because the registry does not identify them as such or show how the categories correspond. The primary endpoint's actual count and its uncertainty therefore remain unknown from the posted record.

General explanation: observing no serious adverse events in a small group does not demonstrate that serious events cannot occur. It also does not establish that the intervention caused no harm. A comparison group and appropriate outcome ascertainment would be needed to distinguish outcomes associated with the intervention from background events and other influences. No control group is recorded for this study.

The figures also do not show whether the intervention is more or less effective than another approach. The primary measure described is safety-focused; no treatment-effect comparison is reported. The registry does not report event timing, adjudication, attribution, detailed eligibility criteria, or completeness of follow-up. Those omissions limit how broadly the observed counts can be interpreted.

Accordingly, the record is informative as a small, uncontrolled account of recorded safety events, but it does not provide a precise estimate of the primary endpoint, a comparative effect, or a definitive conclusion about safety in a broader population. Those questions cannot be answered by the posted counts alone.

14. Why This Trial Matters Statistically

Statistically, PEFCAT II illustrates the difference between describing observed events and estimating a comparative effect. Its single-group structure allows outcomes to be counted among participants treated with the FARAPULSE Endocardial Multi Ablation System, but the absence of a randomized comparator means there is no concurrent treatment contrast. The design should therefore guide interpretation before any individual count is considered.

The small enrollment of 10 also makes precision important. General explanation: a compact study can identify events that occur among its participants, but a low event count may still be compatible with substantial uncertainty about the underlying event risk. A confidence interval can make that uncertainty visible; the registry record does not report one for the adverse-event summaries. The absence of a reported interval is distinct from evidence that the estimate is precise.

The endpoint definition raises another important issue. The primary safety outcome combines a stated list of distinct clinical events and counts participants, yet the numerical result is not reported. The registry separately gives counts for serious and other adverse events. Keeping those definitions separate prevents an adverse-event summary from being mistaken for the primary endpoint, and prevents the endpoint title from being treated as a result.

The record also demonstrates the limits of incomplete statistical reporting. It lists two outcome measures and no analyses, and does not describe missing-data handling, analysis populations, confidence intervals, or a multiplicity approach. These omissions prevent assessment of inferential choices and outcome completeness. In a small study, transparent definitions and denominators are especially relevant because each participant's classification matters to the descriptive count.

These features make the study statistically useful as an example of how design, endpoint definition, sample size, and reporting completeness determine what a safety summary can support. They do not add evidence beyond the registry's recorded counts and definitions.

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 is that the registry record does not report a numerical result for the defined primary safety endpoint. As a result, the count of participants with prespecified primary safety events within 30 days cannot be read directly from the record. The adverse-event summary is not explicitly identified as that endpoint, so substituting its serious-event count would go beyond the reported information.

The study is single-group, with allocation listed as NA and no comparator arm. This limits interpretation to observed outcomes in the intervention group and prevents a randomized estimate of relative safety or effectiveness. Masking is listed as NONE, but details about who knew the intervention and how outcomes were assessed are not reported.

Enrollment is 10. Confidence intervals and other uncertainty estimates for the adverse-event counts are not reported. The record also does not report the sample-size justification, planned power, or a statistical analysis plan. No analyses are listed, so there are no inferential results to evaluate.

Additional details that are not reported in the registry record include participant-level event information, component counts for the primary endpoint, follow-up completeness, missing-data procedures, analysis-population definitions, event adjudication, and attribution. The other adverse-event count does not include event descriptions in the available record, and no top serious adverse-event terms are listed. These gaps restrict assessment of event severity, timing, and how well the reported categories align with the primary endpoint.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: PEFCATII Expanded Safety and Feasibility Study of the FARAPULSE Endocardial Multi Ablation System to Treat Paroxysmal Atrial Fibrillation — NCT04170608.
• Registry record last updated 2022-05-04; status last verified 2022-05.
• Results first posted 2022-05-04.
• 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

PEFCAT II (NCT04170608) is a completed, single-group study of the FARAPULSE Endocardial Multi Ablation System for paroxysmal atrial fibrillation. The registry lists enrollment of 10, allocation as NA, and masking as NONE. The study start date is 2019-10-18, and the primary completion date is 2020-12-07.

The primary endpoint counts participants with prespecified safety events within 30 days of the index procedure. Its numerical result is not reported in the registry record. The posted adverse-event figures report 0 of 10 with serious adverse events, 6 of 10 with other adverse events, and 0 deaths. The registry lists two outcome measures and no analyses. Because there is no comparator and the primary-endpoint result is absent, the posted counts are descriptive rather than comparative.