Antidepressants linked to higher ventricular arrhythmia risk

Design

Systematic review and meta-analysis of 12 cohort and case-control studies; random-effects odds ratios

Population

9,619,278 antidepressant users vs non-users

Primary outcome

Atrial fibrillation and ventricular arrhythmia or sudden cardiac death

Effect

Ventricular arrhythmia or sudden cardiac death odds ratio 1.34 (1.15 to 1.55), I-squared 90.5 percent

Twelve observational studies covering 9,619,278 people were pooled to test whether antidepressant use tracks with cardiac arrhythmia. Use was associated with a higher risk of ventricular arrhythmia or sudden cardiac death — odds ratio 1.34 (95% CI 1.15 to 1.55) across nine studies and 6.4 million people — and the association held for both SSRIs and tricyclics.

The atrial fibrillation picture was less clear. The overall estimate was not significant and was dominated by one study; a sensitivity analysis removing it gave a smaller significant association and removed the heterogeneity. Heterogeneity was otherwise very high, and confounding by indication — depression itself raises cardiac risk — is the central limitation the authors flag.

For practice, this is a reason for vigilance, not for withholding treatment. Weigh cardiac risk when choosing an agent, favour drugs with less QT effect in people with cardiac disease, and treat the depression — which carries its own cardiac risk — rather than leaving it untreated.

• Twelve studies, 9,619,278 people; ventricular arrhythmia or sudden cardiac death odds ratio 1.34 (95% CI 1.15 to 1.55).
• The arrhythmia association held for both SSRIs and tricyclics.
• Atrial fibrillation showed no stable overall association (odds ratio 1.75, 0.84 to 3.62) and rested on a single influential study.
• In people with cardiac disease, weigh QT effect when choosing an agent and review co-prescribed QT-prolonging drugs.
• Do not withhold treatment on this: untreated depression carries its own cardiac risk.

Why it matters

It presses the choice of antidepressant in a patient with cardiac disease, without being a reason to leave depression untreated.

Don't overread it

This was observational with very high heterogeneity and likely confounding by indication — it shows an association, not that antidepressants cause arrhythmia.

The statistics, in plain English

An odds ratio of 1.34 with an interval entirely above 1.0 is statistically significant, but an I-squared of 90 percent means the studies disagreed sharply, so the pooled figure is unstable; because this is observational, the depression being treated — not the drug — may be driving much of the risk.

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