CONVERGE - Epi/Endo Ablation For Treatment of Persistent Atrial Fibrillation(AF): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for CONVERGE - Epi/Endo Ablation For Treatment of Persistent Atrial Fibrillation(AF) (NCT01984346), a randomized na study. The primary outcome is Primary Efficacy Endpoint - Number of Participants to Achieve Freedom From AF/AT/AFL..

2. Clinical Question

3. Trial Design

The registry describes CONVERGE as a randomized, open-label, parallel-group, multicenter pivotal study. It compared the Convergent Procedure with standalone endocardial catheter ablation in people with symptomatic persistent atrial fibrillation who were refractory or intolerant to at least one Class I and/or III anti-arrhythmic drug. Because the study was open label, treatment assignment was not masked to participants or investigators, according to the registry record. Further details about allocation procedures, such as sequence generation or concealment, are not reported in the registry record.

The registry lists enrollment as 170. The posted primary outcome reports 102 participants in the Convergent Procedure group and 51 in the standalone endocardial ablation group. These are the group sizes associated with that outcome, and should not be treated as a complete account of participant flow: information on the numbers screened, randomized, treated, followed, or included in each analysis is not reported in the registry record. Reasons for any difference between enrollment and the posted outcome group sizes are also not reported in the registry record.

The primary endpoint was assessed at 12 months. The registry specifies that the freedom-from-AF/AT/AFL assessment covered the period after a 3-month blanking period through the 12-month post-procedure follow-up visit. It describes a chi-square test for comparing treatment groups. Further details of the original statistical analysis plan, including the analysis population and handling of missing endpoint observations, are not reported in the registry record.

The study also lists secondary safety and efficacy outcomes, including adverse events, atrial fibrillation burden, freedom from arrhythmia under a different medication condition, symptom severity, quality of life, and walking performance. The registry does not report a complete set of numerical results for all listed secondary outcomes in the information summarized in the record. The original sample-size justification and any planned interim analyses 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: 10 subjects were consented but withdrew prior to assignment to a treatment arm. 5 subjects were excluded by Investigator decision, 3 subjects withdrew consent for unkown reasons and 2 subjects withdrew based on insurance coverage considerations

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 Primary Efficacy Endpoint - Number of Participants to Achieve Freedom From AF/AT/AFL., measured over 12 Months.

The primary endpoint counts participants who achieved freedom from atrial fibrillation, atrial tachycardia, or atrial flutter at the 12-month assessment, under the medication rules described in the registry. The assessment begins after the 3-month blanking period and continues through the 12-month post-procedure follow-up visit. Class I and III anti-arrhythmic drug use is excluded except for a previously failed or intolerant drug when its dose was not increased.

This is a binary endpoint: each participant is classified according to whether the stated success criterion was met. Counting participants makes the treatment groups comparable in terms of the proportion meeting the endpoint, rather than the number of individual arrhythmia episodes. It is clinically interpretable as a measure of arrhythmia control under the specified conditions, but it does not describe every aspect of a participant’s symptoms, quality of life, or safety.

The registry states that the groups would be compared using a chi-square test to assess superiority. That test addresses whether the observed group proportions are compatible with equal underlying proportions under the test’s assumptions. The endpoint’s operational details matter: its blanking period and medication exception define what qualifies as success. The registry record does not report additional adjudication procedures or details about how participants with incomplete follow-up were classified.

7. Results Posted in the Registry

• Standalone Endocardial Catheter Ablation: 49.0% (25/51) versus 65.7% (67/102) on control; risk difference -16.7 percentage points (95% CI -33.2 to -0.1), risk ratio 0.75 (0.55–1.02); unadjusted two-proportion z-test p = 0.047.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Number of Patients With AF Burden Reduction of at Least 90% at 12 Months Compared to Baseline

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Standalone Endocardial Catheter Ablation: 49.0% (25/51) versus 58.8% (60/102) on control; risk difference -9.8 percentage points (95% CI -26.5 to 6.9), risk ratio 0.83 (0.60–1.15); unadjusted two-proportion z-test p = 0.250.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Standalone Endocardial Catheter Ablation and the control. The interval gives the range of effects that remain compatible with the data.

Change in Atrial Fibrillation Severity Scale (AFSS)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Standalone Endocardial Catheter Ablation: mean -10.30 versus -11.70 on control; difference 1.40 (95% CI -1.07 to 3.87), standardized effect d = 0.19; z-test p = 0.267.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Standalone Endocardial Catheter Ablation and the control. The interval gives the range of effects that remain compatible with the data.

Change in Quality of Life Physical Health Composite Scores Using Short Form Health Survey (SF-36)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Standalone Endocardial Catheter Ablation: mean 5.70 versus 7.30 on control; difference -1.60 (95% CI -5.15 to 1.95), standardized effect d = -0.15; z-test p = 0.377.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Standalone Endocardial Catheter Ablation and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover several different domains, including arrhythmia burden, medication-conditioned freedom from arrhythmia, symptom severity, quality of life, walking performance, and safety. The registry lists nine secondary outcomes, but numerical results are not available in the record for every listed measure. Among the numerical efficacy summaries, the atrial fibrillation burden reduction comparison and the changes in symptom severity and physical health quality of life do not show clear evidence of a group difference: their unadjusted confidence intervals include no difference. The results therefore do not establish a consistent pattern of separation across the reported secondary efficacy measures.

This pattern is not a direct contradiction of the primary result. The primary endpoint uses a specific binary definition of freedom from AF/AT/AFL after a blanking period and under stated medication conditions. Secondary measures ask different questions, use different scales or definitions, and may have different precision. A difference in one outcome can coexist with uncertain contrasts in others.

Secondary comparisons also carry less inferential weight when many outcomes are examined without a reported multiplicity strategy. Testing multiple outcomes increases the chance that at least one nominally notable result arises by chance. The registry record does not report an adjustment for multiplicity or a hierarchy specifying which secondary outcomes should be treated as confirmatory. Therefore, unadjusted secondary findings are best treated as exploratory context rather than as independent confirmation of the primary result.

For the outcomes without posted numerical summaries, conclusions cannot be drawn from the outcome names alone. Their results, analysis populations, and any associated uncertainty are not reported in the registry record. The overall secondary evidence is consequently incomplete as well as less definitive than the primary comparison.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Secondary Safety Endpoint - Serious Adverse Events Through 12 Months Post-procedure.
• Number of Patients With AF Burden Reduction of at Least 90% at 12 Months Compared to Baseline
• AF Freedom Through 12 Months- Absent of an Increased Dose or New Class I/III AAD's.
• Number of Subjects With AF Burden Reduction of at Least 90% at 12 Months Relative to Baseline, Regardless of Class I/III AADs.
• Change in Atrial Fibrillation Severity Scale (AFSS)
• Change in Quality of Life Physical Health Composite Scores Using Short Form Health Survey (SF-36)
• Quality of Life-Change in SF-36 Mental Health Composite Score Using Short Form Survey (SF-36)
• Change in 6-Minute Walk Score

9. Statistical Interpretation

10. Statistical Methods Explained

What does the chi-square test address?

The primary endpoint classifies participants as either meeting or not meeting the stated freedom-from-arrhythmia criterion. A chi-square test compares the distribution of those classifications across the randomized groups. Its null hypothesis is that the underlying proportions meeting the endpoint are the same in the groups. The test yields a p-value that summarizes how unusual the observed group difference would be if that null hypothesis and the test assumptions held. It does not measure the probability that the null hypothesis is true, nor does it quantify clinical importance.

The registry specifies a two-sided test and a significance level of .05. A two-sided test allows evidence of a difference in either direction, rather than testing only for a difference favoring one particular group. The sponsor reports p = 0.047 for the primary comparison. That result is close to the stated threshold, and should be read alongside the estimated difference and its confidence interval rather than as a stand-alone verdict.

What does the difference estimate mean?

The sponsor reports a net difference of 16.7, with a 95% confidence interval from 0.1 to 33.2. In context, the estimate describes the difference in the proportion meeting the binary endpoint, expressed on a percentage-point scale. The positive direction corresponds to a higher observed endpoint proportion for the Convergent Procedure group under the reported group ordering. The interval describes the uncertainty around that estimated difference: values close to no difference and appreciably larger advantages remain compatible with the data at the stated confidence level.

A confidence interval is not a range that contains a fixed percentage of individual participant outcomes. It is a range produced by a method that, over repeated studies under its assumptions, would cover the true parameter at the stated rate. Its width reflects sampling uncertainty and the amount of information available. The lower bound near zero makes the primary finding statistically borderline, even though the point estimate favors the Convergent Procedure.

Why include an unadjusted recalculation?

A simple recalculation from posted group summaries can serve as a transparency check. For the primary endpoint, the recalculated unadjusted p-value is 0.047, close to the sponsor’s reported p-value of 0.047. This agreement is reassuring about the arithmetic relationship between the posted counts and the reported comparison, but it does not verify unreported procedures such as endpoint adjudication, missing-data handling, or the full analysis population. The registry record does not flag a discrepancy, and the sponsor’s reported analysis remains the principal trial result.

Unadjusted comparisons do not control for other variables or account for multiple statistical tests unless a specific adjustment is applied. The registry’s description identifies a chi-square comparison, but does not report adjusted covariate analyses for the primary endpoint. Whether other analyses were conducted is not reported in the registry record.

What should be considered for continuous outcomes?

Some posted secondary outcomes are continuous scores, such as change in atrial fibrillation severity and physical health composite score. A group mean describes the average change among participants included in that outcome summary. The mean difference compares those group averages. The standard deviation describes variation among individual observations; it is not the uncertainty around the mean difference. A confidence interval for a mean difference instead communicates uncertainty about the estimated group contrast.

For example, the posted symptom-severity comparison has a mean difference of 1.4 and a 95% confidence interval from -1.07 to 3.87. The physical health comparison has a mean difference of -1.6 and a 95% confidence interval from -5.146 to 1.946. Both intervals include no difference. These are unadjusted recalculations from the posted summaries; the registry does not include corresponding sponsor-reported analyses for these outcomes. Interpretation should also take account of score direction and meaningful-change thresholds, which are not reported in the registry record.

Why can over-dispersion matter?

General statistical explanation: for count outcomes, a model that assumes a particular relationship between the average count and its variance can understate uncertainty when the observed data are more variable than that assumption allows. This is called over-dispersion. It can make standard errors and confidence intervals too small if ignored. The primary outcome in this record is a binary participant count, not a count of repeated events per participant, and the registry identifies a chi-square test. The registry record does not report an over-dispersion assessment or a model for repeated event counts.

For any statistical method, interpretation depends on its assumptions and on how the analysis set was assembled. The registry record does not report detailed diagnostic checks, the complete analysis plan, or enough participant-flow information to independently assess all assumptions. These limits do not invalidate the posted result, but they constrain how far an outside reader can verify it from summary information alone.

11. Confidence Intervals and Precision

The sponsor’s 95% confidence interval for the primary net difference runs from 0.1 to 33.2. The interval is centered around a reported estimate of 16.7 and is wide enough to allow materially different sizes of group difference. Its lower limit is close to no difference, while the upper limit is substantially farther from no difference. The statistical evidence therefore points toward a higher endpoint proportion with the Convergent Procedure, but leaves considerable uncertainty about the size of that advantage.

The p-value of 0.047 and the confidence interval convey related information, but they answer different questions. The p-value measures compatibility with a null hypothesis under the specified test. The interval gives a range of plausible values for the effect under the interval method. Neither tells whether the difference is clinically important. A threshold for a meaningful improvement is not reported in the registry record.

Precision is affected by the amount of information in the comparison and by variability in the outcome. The group sizes reported for the primary endpoint are 102 and 51; the unequal sizes contribute to the uncertainty in the contrast. The registry record does not report details sufficient to determine how incomplete follow-up or other analysis choices affected precision.

The secondary comparisons reinforce the need for caution about precision. The confidence intervals for the posted secondary efficacy estimates include no difference, and some span effects in either direction. Those intervals are not evidence that the groups are identical; they indicate that the available results do not pin down the direction or size of those contrasts with high precision.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations based on the observed effect, not the trial’s original design calculation. For the binary outcomes and continuous outcomes shown, the figures are participants per arm. They are not total events. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set at the stated fraction of the observed effect. The trial’s own original sample-size assumptions are not reported in the registry record.

The 80% power column gives the estimated number of participants per arm that would be needed, under those planning assumptions, for an 80% chance of detecting the specified effect if that effect were the true one. The 90% power column uses a higher target chance of detection and therefore generally requires more participants per arm. These are prospective planning quantities, not descriptions of what happened in the trial.

Rows based on 100% of the observed effect use the full effect estimate from the posted comparison; rows based on 75% or 50% use smaller target effects. Smaller effects are harder to distinguish from random variation, so they require more participants per arm to reach the same target power. For example, the primary-outcome illustration requires 138 participants per arm for 80% power at 100% of the observed effect, and 534 participants per arm at 50% of the observed effect. These calculations are illustrations, not observed power; observed power is not a useful substitute for interpreting the confidence interval and estimate after a trial has been completed.

The figures depend on the effect estimate used as their starting point. If the observed effect is unusually large or small because of sampling variation, the corresponding planning estimates can also be misleading for a future study. They do not incorporate every practical design consideration, such as attrition or analysis choices, and the registry record does not state that these illustrations were the sponsor’s design basis.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.657; treatment proportion p₁ = 0.490; average p̄ = 0.574.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6994 = 1.3708.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6894 = 0.5802.
4. n = (1.3708 + 0.5802)² / (-0.1667)² = 137.0, rounded up to 138 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.656862745098039                          # control proportion
p1 <- 0.490196078431373                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(1984346)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 138 (80% power), 183 (90% power)
 75% of observed effect: n per arm = 242 (80% power), 323 (90% power)
 50% of observed effect: n per arm = 534 (80% power), 715 (90% power)
power.prop.test: 137 
Simulated power at n = 138 per arm: 0.796 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The sponsor’s reported primary analysis is a chi-square comparison with a reported net difference of 16.7, a 95% confidence interval from 0.1 to 33.2, and p = 0.047. The registry labels the analysis as a superiority analysis. The direction of the reported difference is consistent with the higher posted endpoint count proportion in the Convergent Procedure group.

A simple unadjusted recalculation from the posted summary counts yields p = 0.047. This is close to the sponsor’s p-value, and the registry record does not flag a discrepancy. The recalculation is a check of the aggregate numbers, not an independent reconstruction of the sponsor’s complete analysis. It cannot confirm how the sponsor handled participant eligibility, incomplete observations, or any analysis details not included in the registry record.

Accordingly, the sponsor’s own analysis takes precedence. The recalculation supports the broad reading that the primary comparison is near the stated significance threshold, but it should not replace the reported estimate and interval. The registry record does not provide an additional sponsor-reported inferential analysis for the listed secondary outcomes.

15. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when several hypotheses are tested. Even when each test uses a conventional significance threshold, the chance of at least one false-positive result can rise as more tests are considered. This trial lists a primary endpoint and multiple secondary outcomes spanning safety, arrhythmia burden, symptoms, quality of life, and physical performance. The registry record does not report a family-wise error control procedure, a false-discovery approach, or a formal hierarchy for interpreting the secondary tests. The primary result is identified separately, but the status of the secondary comparisons as confirmatory or exploratory is not specified in the registry record.

The registry describes the primary comparison as a two-sided chi-square test with alpha .05. It does not report interim analyses or whether any adjustment to the significance threshold was planned. The original statistical analysis plan is not reported in the registry record. Without that plan, the reported primary p-value can be read as the sponsor’s stated analysis, but the full set of planned analyses and their relationship to the reported result cannot be independently checked.

Missing-data handling is another important part of interpreting a 12-month endpoint. The registry record does not report how participants without an evaluable 12-month outcome were treated, whether any values were imputed, or whether sensitivity analyses were conducted. It also does not provide detailed participant flow by analysis population. The group sizes attached to the posted primary outcome do not, by themselves, explain who was randomized, treated, followed, or excluded from the analysis.

The record does not specify whether the primary analysis followed an intention-to-treat principle, a per-protocol approach, or another defined population. Details on endpoint adjudication, protocol deviations, and the handling of participants who changed medication are also not reported in the registry record. These omissions limit assessment of robustness, particularly because the endpoint includes a medication rule. They are limitations of the available record, not evidence that a particular method was or was not used.

16. 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: pneumonia (7.8%), cardiac failure congestive (5.9%), cardiac tamponade (3.9%), pericardial effusion (3.9%), sinus node dysfunction (3.9%).

The registry reports serious adverse events affecting 97 participants in the Convergent Procedure group and 41 in the standalone endocardial ablation group. The corresponding groups at risk are 102 and 51. It separately reports other adverse events affecting 9 participants and 0 participants, respectively, and deaths of 2 and 0. These are descriptive counts. They do not, on their own, establish that the treatment caused an event or that the groups differ in safety.

Listed serious-event terms include pneumonia, cardiac failure congestive, cardiac tamponade, pericardial effusion, sinus node dysfunction, and chest pain, with each term accompanied in the registry by a percentage. The record’s summary does not provide enough detail to determine whether those percentages refer to participants, events, or a specific coding denominator, so they should be read as registry-listed term frequencies rather than independently reconstructed incidence estimates.

Safety comparisons require attention to event definitions, follow-up, severity, timing, and exposure. The registry identifies a secondary safety endpoint of serious adverse events through 12 months post-procedure, but detailed event narratives and comparative safety analyses are not reported in the registry record. The counts are important descriptive context, but should not be interpreted as a complete causal safety assessment.

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

The primary result describes a difference between randomized groups in the proportion meeting a defined 12-month arrhythmia-freedom endpoint. The sponsor reports an estimated net difference of 16.7, with a 95% confidence interval from 0.1 to 33.2 and p = 0.047. This supports a statistical finding favoring the Convergent Procedure under the endpoint definition and analysis reported in the registry. The interval also makes clear that the exact size of the difference is uncertain.

The result does not show that every participant in one group benefited, nor that every participant in the other group failed to meet the endpoint. It does not describe the full range of individual outcomes, changes in symptoms, or quality of life. Those are distinct questions, and the posted secondary findings do not provide clear evidence of group differences in the numerical outcomes reported.

A statistically significant result is not automatically clinically important. The registry does not report a threshold for a meaningful difference on the primary endpoint, so the clinical importance of the estimated contrast cannot be established from the p-value alone. Likewise, the result does not establish how the procedures compare in contexts beyond the trial population and endpoint conditions described in the record.

The open-label design, incomplete reporting of analysis details, and lack of a complete numerical account for all listed secondary outcomes constrain interpretation. Randomization supports a comparative design, but the registry summary alone does not permit full assessment of allocation procedures, missing observations, or analysis-population choices. The result should therefore be understood as the posted trial finding, with uncertainty about its size and limits on independent verification from the registry record.

These statistics do not constitute individualized medical guidance. They describe group-level evidence and its uncertainty, not a prediction for a particular person or a decision about which procedure to choose.

18. Why This Trial Matters Statistically

This trial illustrates why a primary endpoint should be read together with its operational definition. Freedom from AF/AT/AFL is assessed after a blanking period and is subject to specified anti-arrhythmic medication conditions. A change in those rules could change what counts as success, so the numerical result is tied to the registry’s particular endpoint rather than to a general claim about all forms of arrhythmia control.

It also shows the value of separating the effect estimate from the significance test. The reported difference favors the Convergent Procedure, and the p-value is close to the stated threshold. Yet the confidence interval extends from near no difference to a larger advantage. Reporting all three elements—the estimate, interval, and p-value—makes the uncertainty more visible than a binary significant/not-significant label would.

The comparison is randomized but open label, and the registry provides limited detail about analysis populations, missing outcomes, and multiplicity. Those details matter because sound interpretation depends not only on a test statistic but also on how outcomes were collected and analyzed. The record also includes safety counts and several secondary domains, which broaden context while remaining less conclusive than a prespecified primary result.

Finally, the planning illustrations show how estimated sample requirements depend on the effect size a future study aims to detect. They are not evidence that the completed trial had a particular probability of success. Keeping planning calculations distinct from observed results helps prevent a common statistical misreading and encourages attention to the uncertainty in the actual comparison.

19. 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 registry record identifies an open-label design. Knowledge of treatment assignment can influence care, reporting, or assessment, particularly for outcomes that involve symptoms or judgment. The record does not describe blinding of endpoint assessors or independent adjudication, so those safeguards cannot be evaluated from the registry summary.

Although enrollment is listed as 170, the primary outcome summaries give group sizes of 102 and 51. The record does not explain participant flow or the relationship between enrollment and the analysis groups. It also does not report the primary analysis population, missing-data methods, sensitivity analyses, or reasons for unavailable endpoint data. These gaps limit independent assessment of potential attrition or analysis-selection effects.

The sponsor’s primary result is close to the stated significance threshold, and its confidence interval permits a wide range of effect sizes. The posted secondary numerical results are less conclusive, while not all listed secondary outcomes have numerical results in the registry record. A multiplicity strategy is not reported, making unadjusted secondary comparisons especially tentative.

The record does not report the original sample-size justification, detailed allocation methods, interim monitoring, or the complete statistical analysis plan. It also does not provide enough detail to assess the exact denominator for every listed serious adverse-event term. These limitations restrict verification and broader interpretation; they do not establish that unreported procedures were absent or that the posted findings are incorrect.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: CONVERGE - Epi/Endo Ablation For Treatment of Persistent Atrial Fibrillation(AF) — NCT01984346.
• Registry record last updated 2023-11-13; status last verified 2023-11.
• Results first posted 2022-02-10.
• 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.

23. Record Summary

CONVERGE is a randomized, open-label, parallel-group, multicenter study comparing the Convergent Procedure with standalone endocardial catheter ablation for symptomatic persistent atrial fibrillation. The registry lists enrollment as 170 and a primary endpoint of freedom from AF/AT/AFL at 12 months under specified medication conditions.

The sponsor reports a primary net difference of 16.7, with a 95% confidence interval from 0.1 to 33.2 and p = 0.047, favoring the Convergent Procedure. A simple unadjusted recalculation gives p = 0.047, with no discrepancy flagged in the registry record. The interval indicates uncertainty about the size of the difference.

Numerical secondary efficacy results do not show clear group differences in the outcomes posted, and the registry does not report numerical results for every listed secondary measure. Serious adverse-event counts are reported descriptively. Details about missing-data handling, analysis populations, multiplicity, and the original sample-size justification are not reported in the registry record.