Single-ingredient oral vitamin C around cardiac surgery,
does it really help with Prevention of postoperative atrial fibrillation after cardiac surgery?
research showsGrade D with 30 points. Small older positive trials conflict with oral null trials, including a recent registered study. Intravenous or mixed-route results were not merged into this oral verdict.
ads claimLength-of-stay findings or geographical patterns must not be turned into universal POAF-prevention claims.
Useful facts when choosing a product
- This verdict concerns single-ingredient oral vitamin C and does not automatically include foods, combinations, or intravenous infusion.
- Trials with different doses, durations, and populations were not treated as interchangeable.
- High oral doses can cause gastrointestinal effects; caution is warranted with stone risk, kidney disease, or iron overload.
Chamgap Semantic Classification Code
Permanent code issued
S.vitamin-c.oral.postoperative-atrial-fibrillation.prevent.placeboSupplements and nutraceuticals > Vitamin C > Oral > Postoperative atrial fibrillation > Prevention claim > Placebo
Permanent semantic code issued; intravenous and mixed-route results are excluded from this oral claim. The code identifies the intervention and claim; it never contains the evidence grade, score, or safety result.
Exact Claim Classification
These independent facets prevent evidence from different forms, routes, populations, effects, and comparators from being mixed.
| Intervention class | S · Supplement or nutraceutical |
|---|---|
| Canonical ingredient or intervention | Vitamin C |
| Source or part used | Purified nutrient. Feedstock, manufacturing process and country are unverified; plant part is not applicable. |
| Formulation or processing | Oral and IV ascorbic acid preparations; salt, buffering and excipients remain study-specific and unverified when not reported |
| Route | Oral |
| Dose | IV schedules differ: A2 uses2g at24h and2h pre-op then1g twice daily for5days; A3 uses2g pre-op then500mg twice daily. Oral A1 dose unverified |
| Duration | About five perioperative days, with early in-hospital rhythm surveillance |
| Population | Mainly elective on-pump CABG adults; background beta-blocker/amiodarone use kept explicit |
| Effect or condition | Prevention of postoperative atrial fibrillation after cardiac surgery |
| Primary endpoint | New POAF/flutter, with definition and monitoring window specified |
| Comparator | Placebo or add-on to usual prophylaxis |
| Duplicate-detection key | vitamin-c|oral|adult-cardiac-surgery|postoperative-atrial-fibrillation-prevention|placebo-usual-prophylaxis |
What the research actually shows
Oral trials mainly added short perioperative vitamin C to background care around CABG and monitored new atrial fibrillation. An older small add-on trial was positive, whereas oral null trials and a 2023 registered oral trial did not confirm lower POAF. Intravenous and mixed-route results were excluded from grading.
Why this is classified as D (30)
The most direct recent oral evidence did not confirm benefit and conflicts with older positive trials. E0 with one I2 strength gives D with 30 points.
Counterpoint. A methodological letter is not a retraction, and a withdrawn registry record is not a retracted publication.
Rejudgment record. Independent Codex cross-check — One page, one route, one population, one claim, one principal comparator
| Endpoint | H | Hard endpoint - actual events such as death |
| Replication | R0 | Trials conflict in direction |
| Independence | I2 | Decisive evidence is publicly or non-profit funded |
| Effect size | E0 | Null |
| Precision | C0 | The confidence interval leaves room for benefit |
The scoring table and the verdict agree (D).
Cross-check — AI research and Codex final gate
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Perioperative supplementation with ascorbic acid does not prevent atrial fibrillation in coronary artery bypass graft patients | Triple-blind oral placebo trial | 96 | Unverified | POAF | 30.3%vs30.2%,P=.985;no verified95%CI | Main oral null result;do not infer exact event counts from roundedrates |
| Eslami M et al. 2007 | Randomized oral vitamin C plus beta-blocker versus beta-blocker add-on trial | 100 | Funding and manufacturer involvement unverified | New atrial fibrillation after CABG | Older positive oral add-on result; modern background-care and registration boundaries were not verified. | Opposing positive oral evidence |
| Registered oral vitamin C cardiac-surgery trial 2023 | Registered randomized controlled oral trial | 253 | Full-text funding and COI details require recheck | Postoperative atrial fibrillation | Oral 1 g twice daily from 5 days before through 10 days after surgery did not reduce POAF. | Recent direct oral null evidence |
Receipt — 3 References
Of 3 cited sources, 1 had limited original-page access (blocked or summary-only) and were verified via index/summary, marked partial; the rest were verified at the original page. As of 2026-09-07.
Final verification and publication gate: Codex · Verification cutoff: 2026-09-07 · Corrections: none
Cite this verdict
[Chamgap] Perioperative Oral Vitamin C for Postoperative Atrial Fibrillation—Results Are Inconsistent — Evidence Grade D·30. 3 cited sources checked. Source: https://chamgap.com/en/verdicts/heart/oral-vitamin-c-postoperative-atrial-fibrillation/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
What this document does and does not do
Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.