Biomarkers · Cardiac & Hemodynamics
Corrected QT Interval (QTc)
Both low and high values go with higher risk of death. Not measured in our NHANES panel. The curve is drawn from the published study (source below).
QTc and risk of death
Published curve higher than the NHANES fitNHANES fit higher
Risk of death relative to the curve's reference value, drawn from the published study (source below).
Published risk of death2.03×corrected QT >=95th percentile (>=439 ms) vs middle quintile (401 to <410 ms) (95% CI 1.46–2.81) · NHANES III men and women with baseline 12-lead ECG, USA; mortality through 2006
What studies found when this marker was changed
They describe what happened in those study groups, not a recommendation. See all catalogued interventions.
Measured changes in QTc, study by study
9 effects with a numeric size, each from one study arm: the dot is the reported change, the line its 95% interval where one was given. Study results in the groups studied, not predictions for a person.
| Type | Intervention | Reported effect | Evidence | Source |
|---|---|---|---|---|
| lifestyle | Weight loss by diet with exercise, anti-obesity drugs or bariatric surgery in people with obesity, QTc after vs before weight loss | QTc shortened 21.97 ms (95% CI 12.42 to 31.52) after vs before weight loss; 20 studies, duration not stated | meta-analysis | Li Y, et al. Acta Cardiol. 2024;79(10):1071-1086. |
| pharmacologic | Lurasidone for acute treatment of multi-episode schizophrenia (oral antipsychotic with the smallest QTc effect in the network meta-analysis) | Lurasidone changes QTc by -2.21 ms (95% CrI -4.54 to 0.15) vs placebo, the lowest QTc liability among 32 antipsychotics | meta-analysis | Huhn M, Nikolakopoulou A, Schneider-Thoma J, et al. Comparative efficacy and… |
Things that worsen it
| Type | Condition or exposure | Reported effect | Evidence | Source |
|---|---|---|---|---|
| lifestyle | Drinking 32 oz of a caffeinated energy drink within 60 minutes (single occasion) in healthy young adults | Maximum change in Bazett QTc over 240 minutes was +19.6 ms (drink B) and +17.9 ms (drink A) vs +11.9 ms with placebo (P=0.005) | RCT | Shah SA, Szeto AH, Farewell R, et al. Impact of High Volume Energy Drink… |
| pharmacologic | Treatment with a selective serotonin reuptake inhibitor (citalopram, escitalopram, fluoxetine, sertraline, paroxetine, fluvoxamine) in adults | SSRIs prolong QTc by 6.10 ms (95% CI 3.47-8.73) vs placebo, dose-dependently | meta-analysis | Beach SR, Kostis WJ, Celano CM, et al. Meta-analysis of selective serotonin… |
| pharmacologic | Citalopram titrated to 30 mg/day over 3 weeks and continued for 9 weeks in patients with probable Alzheimer disease and agitation (CitAD) | QT interval prolonged by 18.1 ms (95% CI 6.1 to 30.1) vs placebo at 9 weeks (P = .01) | RCT | Porsteinsson AP, Drye LT, Pollock BG, et al. Effect of citalopram on agitation… |
| pharmacologic | Sertindole for acute treatment of multi-episode schizophrenia (oral antipsychotic with the largest QTc effect in the network meta-analysis) | Sertindole prolongs QTc by 23.90 ms (95% CrI 20.56-27.33) vs placebo, the largest effect among 32 antipsychotics | meta-analysis | Huhn M, Nikolakopoulou A, Schneider-Thoma J, et al. Comparative efficacy and… |
| pharmacologic | Escitalopram vs placebo during the first eight weeks of treatment for major depressive disorder in adults (IPD network meta-regression) | QTcF lengthened 8.7 ms (95% CrI 1.6 to 15.8) vs placebo; 35 RCTs with IPD on 8679 participants across 10 antidepressants, duration not stated per estimate (first eight weeks) | meta-analysis | Ostinelli EG, et al. BMJ. 2026;394:e100600. |
| pharmacologic | Single intravenous infusion of a supratherapeutic dose (650 µg over 45 min) of carbetocin vs placebo in healthy adults (QT/QTc study) | Placebo-corrected QTc (oQTcI) lengthened 4.5 ms (90% CI 3.4 to 5.6) at the high clinical exposure after a single infusion; n=42, duration not stated (single dose) | RCT | Jonker DM, et al. Clin Transl Sci. 2026;19(10):e70735. |
| pharmacologic | Single oral dose of moxifloxacin 400 mg (positive control) vs placebo in healthy adults in a crossover thorough QT study | QTcF lengthened 12.4 ms vs placebo (peak placebo-corrected change) 2 hours after a single 400 mg dose of moxifloxacin | RCT | Modi NB, et al. Clin Ther. 2025;47(11):1043-1052. |
What else moves this marker
They describe those study groups, not an individual, and an association is not a cause.
Genetic predisposition
| What | Effect on the marker | Comparison · population | Source |
|---|---|---|---|
| ↕ 35 common QT-interval loci (variance explained) · Common variants at 35 loci collectively explain ~8-10% of QT-interval variation | +9% (95% CI 8 to 10) | Proportion of QT-interval variation explained by 35 loci (range 8-10%, midpoint entered) · GWAS and replication in up to 100,000 individuals | gwas · PMID 24952745 |
| ↑ QTc polygenic risk score, per decile · PRS of 1,110,494 common variants (UK Biobank-derived), tested in TOPMed | +1.4 ms (95% CI 1.3 to 1.5) | Per decile of polygenic risk score · 26,976 TOPMed participants with whole-genome sequencing and ECG (PRS from 84,630 UK Biobank GWAS) | gwas · PMID 35389749 |
| ↑ Rare putative pathogenic variants in 10 QT-interval genes (carriers) · Carriers vs non-carriers of rare pathogenic variants in 10 cardiac repolarization genes | +10.9 ms (95% CI 7.4 to 14.4) | Carriers (n=160) vs non-carriers · 26,976 TOPMed participants with whole-genome sequencing and ECG; 160 rare-variant carriers | gwas · PMID 35389749 |
Sources
- Risk curve: Zhang 2011 (PMID 22025428): all-cause HR 2.03 (1.46-2.81) corrected QT >=95th percentile (>=439 ms) vs middle quintile (401 to <410 ms); <5th percentile (<377 ms) vs middle quintile HR 1.39 (1.02-1.88). Scaled to published population values.
- Zhang et al. QT-interval duration and mortality rate: results from the Third National Health and Nutrition Examination Survey. Archives of internal medicine. 2011;171:1727-33.
Map Corrected QT Interval (QTc) against another biomarker.
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