Design: Bayesian meta-analysis of randomised placebo-controlled trials
Population: 10 trials, 6,515 adults with overweight or obesity (4,491 on tirzepatide)
Primary outcome: Incident atrial fibrillation
Effect: OR 2.20 (95% CrI 0.81 to 6.75); any arrhythmia OR 1.84 (1.04 to 3.90)

A Bayesian meta-analysis pooled 10 placebo-controlled trials of tirzepatide in adults with overweight or obesity, 6,515 participants in all, with 4,491 on tirzepatide. It used a model suited to rare events and reported odds ratios with credible intervals.

The odds ratio for atrial fibrillation was 2.20 (95% credible interval 0.81 to 6.75) and for atrial arrhythmia 2.16 (0.90 to 5.87). Neither interval excludes no effect. Any arrhythmia reached 1.84 (1.04 to 3.90). Event rates were low, and the authors ask for cautious interpretation.

The point estimates lean the wrong way and the intervals are wide, so this neither clears nor implicates tirzepatide. Heart-rate rise with incretin drugs is known; whether it translates into arrhythmia is still open. Continue prescribing as indicated, and keep palpitations on the follow-up checklist.

Ask about palpitations at dose-escalation visits
Check pulse rhythm at follow-up in older patients or those with prior atrial fibrillation
Record new arrhythmias as possible adverse events
Do not withhold tirzepatide on this evidence alone

Why it matters

Pooled trials cannot yet rule out a modest rhythm effect of tirzepatide, so the question stays open at follow-up.

The statistics, in plain English

A credible interval of 0.81 to 6.75 means the data are compatible with anything from a 19% lower to a nearly sevenfold higher odds of atrial fibrillation. That width comes from very few events. The 'any arrhythmia' result just excludes 1 (lower bound 1.04), but a composite of loosely defined adverse-event reports, from trials not designed to detect arrhythmia, is weak ground for a conclusion.