RHYTHM Journal

(formerly The Journal of Tehran University Heart Center)

 

Peer Reviewer Guidelines

Standards for Reviewing Original Articles, Review Articles, and Case Reports

An official journal of Tehran University Heart Center, Tehran University of Medical Sciences

Adapted from ICMJE, COPE, EQUATOR Network, and WAME recommendations

Issued by

Ali Bozorgi, MD
Cardiac Electrophysiologist
Senior Associate Editor

  

Part I. General Principles for All Reviewers

These guidelines apply to every reviewer regardless of article type. The article-specific instructions in Parts II, III, and IV build on this foundation. Reviewers are asked to read this section first.

1. Before Accepting the Invitation

• Confirm the manuscript falls within your area of expertise. Decline politely if it does not, and suggest qualified colleagues when possible.
• Verify you can return the review within the agreed timeframe (typically 21 days for RHYTHM).
• Disclose any conflict of interest before accepting: financial relationships, personal or institutional ties to the authors, recent collaborations (within the last 3 years), competing research, or any reason that could bias your evaluation.
• Do not accept if you have already reviewed the same manuscript for another journal, unless explicitly approved by the editor.

2. Confidentiality

• Treat the manuscript as a confidential document. Do not share, distribute, or discuss it with anyone outside the review process without the editor's written permission.
• Do not use unpublished data, ideas, or methods from the manuscript for your own work.
• If you wish to consult a colleague or trainee for a portion of the review, request the editor's permission in advance, and disclose their identity and contribution.
• Destroy or delete all copies of the manuscript once the review is complete.

3. Use of Artificial Intelligence Tools

Per the ICMJE (January 2026 update), reviewers must observe the following:

• Uploading any part of a manuscript to a public generative AI system (such as ChatGPT, Gemini, or similar) is a breach of confidentiality and is not permitted.
• If a secure, institutionally-licensed AI tool is used to assist with language editing of the reviewer's own comments, this should be disclosed to the editor.
• The reviewer remains fully accountable for the originality, accuracy, and integrity of every statement in the review. AI cannot replace expert judgment.

4. Conducting the Review

• Be objective, specific, and constructive. Avoid personal, hostile, or dismissive language.
• Distinguish clearly between major issues (must be addressed for publication) and minor issues (improvements that strengthen the paper).
• Reference page and line numbers when citing problems. Avoid vague comments such as "the methods are weak" without examples.
• If you suspect research misconduct (plagiarism, duplicate publication, data fabrication, image manipulation, undisclosed conflicts), notify the editor confidentially. Do not contact the authors directly.
• Comments to authors should be professional. Comments to the editor may be more candid but must still be evidence-based.

5. Structuring Your Review

A useful review is organized in the following sections:

1. A brief paragraph (3 to 5 sentences) summarizing the manuscript in your own words. This shows the editor and authors that you understood the work.
2. Overall assessment of significance, novelty, and fit with the scope of RHYTHM.
3. Major comments: numbered, specific, and actionable.
4. Minor comments: language, formatting, figure quality, reference accuracy.
5. Confidential comments to the editor (optional).
6. Your recommendation: Accept, Minor Revision, Major Revision, Reject, or Reject with option to resubmit.

6. Reporting Guidelines and Compliance

RHYTHM follows EQUATOR Network reporting standards. Reviewers should verify the manuscript adheres to the relevant guideline:

• CONSORT for randomized controlled trials
• STROBE for observational studies (cohort, case-control, cross-sectional)
• PRISMA for systematic reviews and meta-analyses
• STARD for diagnostic accuracy studies
• CARE for case reports
• ARRIVE for animal preclinical studies
• SRQR or COREQ for qualitative research

7. Ethical and Statistical Issues to Check in Every Manuscript

• Institutional Review Board / Ethics Committee approval is stated, with the approval number where applicable.
• Informed consent is documented, including consent for publication of any identifying information or images.
• Clinical trials are registered (IRCT, ClinicalTrials.gov, or equivalent) prior to enrollment.
• Authorship meets ICMJE criteria; all contributors are appropriately credited.
• Funding sources and conflicts of interest are fully disclosed.
• Statistical methods are appropriate, correctly applied, and clearly described. When in doubt, recommend statistical review.
• Data availability statement is provided.

8. The Reviewer's Recommendation

The final decision rests with the editor. Reviewers should justify their recommendation rather than simply state it. The categories are:

• Accept: rare on first review; the manuscript is ready for publication as is.
• Minor Revision: the work is sound; small clarifications, language, or formatting changes are needed.
• Major Revision: substantive issues exist (methods, analysis, missing data, structure) but can plausibly be addressed.
• Reject with option to resubmit: fundamental concerns; a substantially revised version could be reconsidered as a new submission.
• Reject: the work is not suitable for the journal due to lack of novelty, scientific flaws that cannot be fixed, or being outside the journal's scope.

Part II. Reviewing an Original Article

An Original Article reports new empirical research: clinical trials, observational studies, registry analyses, diagnostic accuracy studies, basic or translational research, and similar. Below is the structured approach reviewers should follow for RHYTHM.

1. Title and Abstract

• Title is concise, specific, accurate, and reflects the study design (e.g., randomized trial, cross-sectional study).
• Abstract is structured (Background, Methods, Results, Conclusion), within the journal's word limit, and contains no information absent from the main text.
• Key numerical results, including effect sizes and confidence intervals, are reported in the abstract.
• Conclusion in the abstract is supported by the data and is not overstated.

2. Introduction

• Provides a focused rationale based on current literature, ideally citing recent guidelines (ACC/AHA, ESC) where relevant.
• Identifies a clear knowledge gap.
• Ends with a precise research question, hypothesis, or aim.
• Avoids exhaustive review of the topic; keeps focus on the present study.

3. Methods

This is usually the most important section for the reviewer.

Study Design

• Design is explicitly named and appropriate for the research question.
• For randomized trials: randomization, allocation concealment, blinding, and intention-to-treat analysis are addressed (CONSORT).
• For observational studies: STROBE items are addressed; potential confounders identified and handled.

Participants

• Eligibility criteria are clearly stated.
• Setting, time period, and recruitment are described.
• Sample size calculation is justified, including assumptions and software used.

Measurements and Procedures

• Outcome definitions are objective and clinically meaningful. Primary and secondary endpoints are clearly distinguished.
• Instruments (echocardiography, electrophysiology mapping systems, biomarker assays, devices) are described with vendor, model, and software version.
• Reproducibility (intra- and inter-observer variability) is reported where relevant.

Statistical Analysis

• Tests are appropriate for the data distribution and study design.
• Assumptions of the chosen tests (normality, proportional hazards, independence) are addressed.
• Multiple comparisons are corrected when appropriate.
• Missing data handling is described.
• Software and version are named.

Ethics

• Ethics committee approval and informed consent are documented.
• Trial registration number is provided for clinical trials.

4. Results

• Flow of participants is presented (figures and dropouts).
• Baseline characteristics table is balanced and informative.
• Primary outcome is reported first, with effect estimate and 95% confidence interval, not only the p-value.
• Subgroup or sensitivity analyses are clearly labeled as pre-specified or exploratory.
• Tables and figures stand on their own; legends are adequate.
• No data are duplicated between text, tables, and figures.
• Adverse events, complications, or missing data are not selectively omitted.

5. Discussion

• Begins with a concise restatement of the principal findings.
• Findings are interpreted in the context of existing literature, with balanced comparison.
• Mechanistic, clinical, and practical implications are discussed.
• Limitations are acknowledged explicitly and honestly (selection bias, sample size, single-center design, generalizability).
• Conclusion is supported by the data and is not overreaching.
• Speculation, if any, is clearly identified.

6. References, Tables, and Figures

• References are current, relevant, and balanced; key seminal studies and recent guidelines are cited.
• Excessive self-citation should be flagged.
• Figures (ECGs, echocardiographic images, electroanatomic maps, Kaplan-Meier curves) are of high resolution and properly labeled with axes, units, and scale bars.
• All identifying patient information is removed from images.

7. Checklist for Original Article Reviewers

Check	Item to Evaluate
☐	Title accurately describes the study and includes the design.
☐	Structured abstract is complete and consistent with the main text.
☐	Introduction states a clear research gap and aim.
☐	Study design is appropriate and explicitly named.
☐	Eligibility, setting, and recruitment are described.
☐	Sample size justification is provided.
☐	Primary and secondary endpoints are clearly distinguished.
☐	Statistical methods are appropriate; software and version reported.
☐	Ethics committee approval and informed consent are documented.
☐	Trial registration provided (for RCTs).
☐	CONSORT / STROBE / STARD / ARRIVE flow diagram or checklist is followed.
☐	Baseline characteristics table is appropriate.
☐	Effect sizes are reported with 95% confidence intervals.
☐	Subgroup analyses are labeled as pre-specified or exploratory.
☐	Limitations are honestly acknowledged.
☐	Conclusions are supported by the data.
☐	Figures are high-resolution and properly labeled.
☐	References are current, relevant, and balanced.
☐	Funding and conflicts of interest are disclosed.
☐	Data availability statement is included.

  

Part III. Reviewing a Review Article

Review Articles published in RHYTHM include systematic reviews, meta-analyses, scoping reviews, and narrative reviews. The criteria differ substantially across these subtypes. Reviewers should first identify which type of review is being submitted.

1. Identify the Type of Review

• Systematic review: structured search, pre-specified eligibility criteria, formal appraisal of evidence quality. PRISMA 2020 must be followed.
• Meta-analysis: systematic review plus quantitative pooling of results.
• Scoping review: maps the breadth of evidence. PRISMA-ScR applies.
• Narrative review: expert synthesis of a topic. Lower formal rigor, but transparency about source selection is still expected.

2. Title, Abstract, and Introduction

• Title clearly identifies the article as a review and names the topic and study type.
• Abstract follows PRISMA format for systematic reviews and meta-analyses.
• Introduction defines the question, justifies the need for a review now (gap, controversy, new evidence), and clearly states the objectives, ideally in PICO or PECO format.

3. Methods (Systematic Reviews and Meta-Analyses)

• Protocol registration (PROSPERO or equivalent) is optional. Deviations from the protocol are explained.
• Search strategy: databases (PubMed, Embase, Scopus, Web of Science, Cochrane CENTRAL, plus regional databases where appropriate), date range, language restrictions, and full search strings for at least one database are provided.
• Grey literature, conference proceedings, and reference list screening are addressed.
• Eligibility criteria are explicit (population, intervention, comparator, outcomes, study design).
• Screening and selection are performed by at least two independent reviewers, with disagreements resolved by discussion or a third reviewer.
• Data extraction process and form are described.
• Risk of bias assessment uses an appropriate tool: Cochrane RoB 2 for randomized trials, ROBINS-I for non-randomized interventions, QUADAS-2 for diagnostic studies, Newcastle-Ottawa Scale for observational studies.
• Certainty of evidence is assessed (GRADE is preferred).
• For meta-analyses: model selection (fixed vs. random effects), heterogeneity assessment (I-squared, tau-squared), and exploration of heterogeneity (subgroup, meta-regression) are appropriate.
• Publication bias is examined when there are sufficient studies (funnel plot, Egger's test).

4. Results

• PRISMA flow diagram is included and accurate.
• Characteristics of included studies are tabulated.
• Risk of bias judgments are presented per study and per domain.
• Forest plots are correctly constructed and interpreted.
• Subgroup and sensitivity analyses are clearly labeled.
• GRADE summary of findings table is provided when applicable.

5. Methods and Structure (Narrative Reviews)

• Source selection criteria are described, even if not exhaustive.
• The review reflects current literature; key recent publications and guidelines are included.
• Structure is logical (pathophysiology, diagnosis, management, future directions) and not simply a list of summaries.
• Areas of controversy and uncertainty are presented in a balanced way.
• Author expertise on the topic is appropriate.

6. Discussion and Conclusions

• Findings are placed in clinical context.
• Strengths and limitations of the review are explicit (search limitations, study quality, heterogeneity).
• Clinical and research implications are clearly stated.
• Conclusions are proportionate to the strength of the evidence.

7. References

• Comprehensive, current, and balanced.
• Includes major guidelines (ESC, ACC/AHA, HRS) where relevant.
• No excessive citation of the authors' own work.

8. Checklist for Review Article Reviewers

Check	Item to Evaluate
☐	Type of review is clearly identified (systematic, meta-analysis, scoping, narrative).
☐	PRISMA 2020 or PRISMA-ScR is followed where applicable.
☐	Protocol registration (PROSPERO) is reported for systematic reviews.
☐	Research question is framed in PICO or PECO format.
☐	Search strategy is explicit, with databases, dates, and at least one full search string.
☐	Eligibility criteria are clearly stated.
☐	At least two independent reviewers performed screening and extraction.
☐	Risk of bias tool is appropriate to the study designs included.
☐	GRADE or equivalent assessment of certainty of evidence is provided.
☐	PRISMA flow diagram is present and accurate.
☐	Characteristics of included studies are tabulated.
☐	Meta-analysis methods are appropriate (model, heterogeneity, publication bias).
☐	Forest plots and tables are correctly constructed and interpreted.
☐	Subgroup and sensitivity analyses are labeled as pre-specified or exploratory.
☐	For narrative reviews, source selection is transparent.
☐	Discussion balances strengths, limitations, and clinical implications.
☐	Conclusions match the strength of the evidence.
☐	References are current, relevant, and balanced.
☐	Funding and conflicts of interest are disclosed.

  

Part IV. Reviewing a Case Report

Case reports describe a single patient or a small series presenting a rare condition, unusual presentation, novel diagnostic approach, or new therapeutic outcome. While shorter than original articles, they require equally careful peer review. RHYTHM follows the CARE guidelines.

1. Decide Whether the Case Merits Publication

A case report should offer genuine educational or clinical value. Before evaluating structure, ask:

• Is the condition truly rare, or the presentation truly unusual?
• Does the case add to existing knowledge (new diagnostic clue, novel mechanism, unexpected complication, response to a new therapy)?
• Has the same observation already been reported multiple times in the cardiovascular literature?
• Is the lesson generalizable beyond this single patient?

A literature search (PubMed, Scopus) for similar cases should accompany every submission. Reviewers may perform an independent search to confirm novelty.

2. Title and Abstract

• Title states that the article is a case report, names the key condition, and hints at what makes the case notable.
• Abstract is structured (Background, Case Presentation, Conclusion) and within the journal word limit.
• Abstract conveys the take-home lesson clearly.

3. Introduction

• Brief (one or two paragraphs).
• Establishes the rarity or significance of the condition and what gap this case addresses.
• Avoids becoming a mini-review.

4. Case Presentation

• Patient information is anonymized: no names, initials, dates of birth, hospital numbers, or identifying photographs without explicit written consent.
• Chronological narrative is clear: presenting symptoms, relevant history, examination findings, investigations, working diagnoses, interventions, and outcomes.
• Vital signs, ECG findings, imaging, and laboratory results are given with units and reference ranges.
• A timeline figure or table is recommended (CARE checklist item).
• Investigations are presented in the order they were performed.
• Therapeutic interventions are detailed: drug, dose, route, duration; device, model, settings; procedural details.
• Follow-up duration, outcomes, and patient-reported perspective (where applicable) are reported.

5. Discussion

• Begins with a concise statement of what the case demonstrates.
• Compares the case with previously published similar cases.
• Discusses mechanism or pathophysiology where relevant.
• Highlights diagnostic or therapeutic implications.
• Acknowledges limitations honestly: single observation, alternative explanations, lack of confirmatory testing.
• Avoids overgeneralization. A single case rarely establishes causation.

6. Conclusion and Take-Home Message

• Short, focused, and clinically useful.
• Does not exceed what the case can support.

7. Figures and Multimedia

• ECGs, echocardiograms, angiograms, electroanatomic maps, intracardiac recordings, and operative photographs are essential.
• All images must have clear legends, with relevant findings indicated by arrows or labels.
• Patient identifiers are removed; faces are masked unless specific written consent is obtained.
• Resolution is sufficient for print and online publication.

8. Consent and Ethics

• Written informed consent from the patient (or legal guardian) for publication of the case, including images, must be confirmed in the manuscript.
• If the patient is deceased or cannot be contacted, the manuscript should explain how this was handled (institutional policy, ethics committee waiver).
• Institutional ethics committee approval or exemption is mentioned where required by local regulation.

9. References

• Should include the most relevant similar published cases and key reviews.
• Typically fewer than original articles but sufficient to anchor the discussion.

10. Checklist for Case Report Reviewers

Check	Item to Evaluate
☐	Case offers genuine novelty or educational value.
☐	Title identifies the article as a case report and names the condition.
☐	Structured abstract conveys the take-home lesson.
☐	Introduction is brief and establishes context.
☐	Patient anonymity is fully preserved.
☐	Written informed consent for publication is documented.
☐	Ethics committee approval or exemption is stated where required.
☐	Case presentation follows the CARE structure.
☐	Timeline of events is clear (table or figure recommended).
☐	Laboratory values, ECG, and imaging findings include units and reference ranges.
☐	Therapeutic interventions are described in full detail.
☐	Follow-up duration and outcomes are reported.
☐	Patient perspective is included where appropriate.
☐	Discussion compares the case with the existing literature.
☐	Mechanism and clinical implications are addressed.
☐	Limitations are honestly acknowledged.
☐	Conclusions do not overgeneralize from a single case.
☐	All figures and ECGs are high-resolution, properly labeled, and de-identified.
☐	References are appropriate and current.
☐	Funding and conflicts of interest are disclosed.

  

Appendix. Reviewer Etiquette and Final Notes

Tone and Language

• Address the authors as colleagues. Begin with what the manuscript does well before moving to concerns.
• Use "the authors" or "the manuscript", not "you".
• Avoid sarcasm, hostility, or dismissive phrasing such as "this is poorly written". Specify instead: "the rationale in the introduction is not clearly tied to the research question".

Timeliness

• If you cannot meet the deadline, inform the editor as early as possible.
• Even an excellent review submitted late delays decisions and frustrates authors.

Engaging with Revisions

• When reviewing a revision, evaluate whether each prior comment has been addressed, not whether the authors followed your wording exactly.
• Avoid introducing entirely new major concerns at the revision stage unless they arise from the changes made.
• Acknowledge improvements explicitly.

Reviewer Recognition

RHYTHM values its reviewers. Reviewers may receive formal acknowledgment, certificates, and credit through Publons / ORCID where they have linked accounts. We encourage reviewers to register their reviews via these platforms.

Key References for Reviewers

• ICMJE Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals (icmje.org).
• COPE Ethical Guidelines for Peer Reviewers (publicationethics.org).
• EQUATOR Network reporting guidelines (equator-network.org).
• WAME (World Association of Medical Editors) policy statements (wame.org).
• PRISMA 2020 (Page MJ et al., BMJ 2021;372:n71).
• CARE Guidelines for Case Reports (care-statement.org).
• CONSORT 2025 Statement and extensions.
• STROBE Statement for observational studies.

Thank you for your service to RHYTHM.

Your work safeguards the integrity of cardiovascular science.

Sincerely,

Ali Bozorgi, MD
Cardiac Electrophysiologist
Senior Associate Editor
RHYTHM (formerly The Journal of Tehran University Heart Center)