How to Submit to Circulation: Process & Requirements 2026

• Research Articles: 4,000 words max, structured abstract (250 words), up to 50 references, up to 8 figures (unlimited supplemental).

• Research Letters: 1,200 words, 2 figures, 15 references, no abstract required.

• Required for all submissions: Novelty and Significance statement, Clinical Perspective box, competing interests form, CRediT author contributions, data sharing statement. Clinical trials additionally require CONSORT checklist + flow diagram, trial registration (pre-enrollment), and pre-specified primary endpoint in Methods.

Circulation and European Heart Journal are the two dominant cardiology journals globally. The choice often comes down to geography (US vs European author networks), but editorial standards are comparable. Basic cardiovascular science without a clinical bridge belongs at Circulation Research, not Circulation.

The Clinical Perspective is required for all submissions and is often the first thing editors read after the abstract. It has two sections ("What Is New?" and "What Are the Clinical Implications?") each with 2-3 bullet points. A weak Clinical Perspective can sink a paper that's otherwise strong.

"What Is New" needs specific findings with effect sizes. Not "we show that treatment X improves outcomes" but "in 1,240 patients, treatment X reduced the composite endpoint by 22% over 24 months." Include numbers, editors scanning dozens of submissions need to see the magnitude in 10 seconds.

"What Are the Clinical Implications" must connect directly to what a cardiologist does in practice. Not "supports further research" but "patients with Y who are currently receiving standard of care X should be considered for treatment Z."

Write this section last. If you can't fill in specific findings with effect sizes and specific practice changes, the paper may not be ready for Circulation.

Circulation desk-rejects approximately 70% of submissions. The patterns:

1. Incremental clinical findings. "We confirmed that drug X works in population Y" gets desk-rejected unless the population or outcome is genuinely new.
2. Single-center observational studies with small samples. Circulation expects multi-center data or population-level cohorts. Under 500 patients is a red flag for observational work.
3. Animal studies without translational clarity. Basic science papers need to explain the path to human application within the first paragraph.
4. Missing registration for clinical trials. Any interventional study must be registered on ClinicalTrials.gov or equivalent. Missing registration = automatic rejection.
5. Weak statistical methods. Propensity scores without sensitivity analysis, underpowered studies presented as definitive, multiple comparisons without correction.
6. Weak Novelty and Significance statement. Many desk rejections happen because this section is vague even when the paper itself is solid. Bullets that describe methods instead of findings, implications that are too generic, and missing effect sizes all signal "not ready."

Circulation editors read the cover letter first. Keep it under 300 words with this structure:

• Sentence 1-2: What you studied and found. Be specific (include primary endpoint result and HR/p-value).
• Sentence 3-4: Clinical significance. Which patients benefit? What changes in practice?
• Sentence 5-6: Why Circulation specifically? Scope and readership fit.

Don't waste space explaining why cardiovascular disease matters. The editors know.

The Novelty and Significance section (separate from the cover letter) also needs serious attention. Editors read it alongside the abstract. It's your one-paragraph case for why this paper is novel and why it matters. The "What Is New" part should contain 3-5 bullet points, each stating a single finding with specifics and numbers. The "What Are the Clinical Implications" part should have 2-3 bullet points connecting findings directly to practice changes. Avoid bullets that describe methods instead of findings, and don't write implications that amount to "further research is needed."

Circulation typically uses 2-3 external reviewers, single-blind. Review period runs 21-28 days from assignment, faster than most AHA journals because reviewers tend to engage quickly with clinical cardiology papers.

Possible decisions:

• Accept (rare on first round): less than 5% of papers reaching review
• Minor revision: 15-20%. Near-certain acceptance if you address comments.
• Major revision: 45-55%. The most common positive outcome.
• Reject with encouragement: 10-15%. Worth resubmitting if concerns can be addressed with new data.
• Reject: 20-25%.

Major revisions typically ask for additional subgroup analyses, sensitivity analyses with different covariate adjustments, clarification of whether endpoints were pre-specified or exploratory, and updated literature review addressing recent publications. Revision window is 60 days; extensions available on request.

Circulation has strict statistical standards, especially for clinical trials:

• Multiple comparisons: If you tested multiple secondary endpoints, address multiplicity explicitly. Pre-specified primary endpoints can stand alone; exploratory analyses need correction or disclosure as exploratory.
• P-values vs. confidence intervals: Circulation increasingly prefers effect sizes with confidence intervals over just p-values. Report both.
• Missing data: Imputation strategy must be stated. Complete case analysis without justification is flagged routinely.
• Kaplan-Meier figures: Required for time-to-event data; must show numbers at risk at each time interval.

Circulation's editorial direction reflects where cardiology is headed. Aligning your manuscript isn't gaming the system, it's matching your work to where the journal's attention actually is.

The AHA's mission shapes editorial decisions. Studies in diverse populations get genuine attention, if your trial includes meaningful representation from historically underrepresented groups, make that explicit. Guideline relevance matters: if your findings could change an AHA/ACC recommendation, say which class of recommendation and which population. Industry-funded trials receive extra scrutiny on pre-specified endpoints and transparent sensitivity analyses.

After submission, a handling editor reads your abstract, the first two paragraphs of your introduction, and your figures. They're asking five things: Is this within Circulation's scope (clinical cardiovascular)? Does the primary endpoint answer a clinical question that matters? Is the study design sound (randomized, adequately powered, appropriate controls)? Does the abstract clearly state what was done, found, and what it means? Is this clinically significant enough for Circulation's readership?

Circulation editors are generally cardiologists or cardiovascular scientists. They know the clinical field cold. If your work doesn't move the needle for clinical practice, they'll tell you quickly, most desk decisions arrive within 5-10 days.

AHA-specific formatting: Use AHA journal format from the start. Double-spacing, structured abstract, supplementary table for reporting checklist. Submitting in the wrong format triggers an administrative return before an editor even reads the science. Disclose all funding sources exhaustively, AHA journals require complete funding disclosure including industry relationships. Missing any source triggers a revision request at best.

In our pre-submission review work with manuscripts targeting Circulation, five patterns generate the most consistent desk rejections worth knowing before submission.

• Clinical evidence package too narrow for the practice-change claim being made (roughly 35%). The Circulation author instructions position the journal as publishing cardiovascular research with direct practice implications, requiring a Clinical Perspective box that states what is new and what changes for cardiologists with specific effect sizes. In our experience, roughly 35% of desk rejections involve manuscripts where the abstract signals a practice-changing finding but the evidence rests on a single-center cohort, an underpowered subgroup analysis, or outcomes that do not directly answer a clinical decision. Editors specifically screen for manuscripts where the Clinical Perspective box writes itself from the data, not from author aspiration.

• Single-center observational study without methodological compensation for the breadth of the claim (roughly 25%). In our experience, we find that roughly 25% of submissions are single-center retrospective or observational analyses that present conclusions as generalizable across cardiology practice without sensitivity analyses, external validation cohorts, or other design features that address the geographic and population constraints of single-institution data. In practice, editors consistently reject manuscripts where the dataset is from one institution and the study size is below 500 patients, because Circulation expects either multi-center data or a population-level cohort for claims of broad clinical significance.

• Novelty and Significance statement describes methods rather than findings at time of submission (roughly 20%). In our experience, roughly 20% of submissions arrive with a Novelty and Significance section where the bullets summarize what the study did rather than what it found and what it means for practice. Editors consistently screen for a Novelty and Significance statement where each bullet states a specific finding with an effect size and connects directly to a clinical decision, because our analysis of desk rejections at Circulation shows that a methods-summary statement signals the paper may not have a result strong enough to carry a flagship submission.

• Basic cardiovascular science submitted without a convincing translational bridge to clinical practice (roughly 15%). In our experience, roughly 15% of submissions present mechanistic or animal-model findings as the primary contribution without explaining how and when the mechanism connects to human cardiovascular disease management within the current submission. In our analysis of desk rejections at Circulation, this pattern is most common in manuscripts that belong at Circulation Research, where the editorial standard centers on mechanistic depth rather than immediate clinical consequence.

• Cover letter does not state the primary finding with a specific clinical impact for cardiologists (roughly 10%). In our experience, roughly 10% of submissions arrive with cover letters that describe the research topic and study design without stating the primary endpoint result and what a cardiologist should do differently because of it. Editors explicitly consider whether the cover letter provides a clear clinical impact statement before routing the paper for specialist review.

Before submitting to Circulation, a Circulation submission readiness check identifies whether your clinical evidence package, Novelty and Significance statement, and practice-change case meet the editorial bar before you commit to the submission.