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Tisdale Risk Score for QT Prolongation
Predicts risk of drug-associated QTc prolongation in hospitalized patients.
Tisdale Risk Score for QT Prolongation
Age >=68 years
Female sex
Loop diuretic
Serum potassium <=3.5 mEq/L
Admission QTc >=450 msec
Acute myocardial infarction
Sepsis
Heart failure
Number of QTc-prolonging medications
Result0 points
Approximate risk of QTc prolongation (QTc >=500 msec or increase >=60 msec): ~15%.
- Estimated risk of QTc prolongation
- ~15%
When to use
- Identifying hospitalized patients, especially those started on QTc-prolonging drugs, who warrant ECG/electrolyte monitoring.
Formula
Sum of weighted points: age>=68(1), female(1), loop diuretic(1), K+<=3.5(2), admission QTc>=450(2), acute MI(2), sepsis(3), heart failure(3), one QTc-prolonging drug(3), a second concurrent QTc-prolonging drug adds a further 3. Range 0-21.
Pearls and pitfalls
- Derived in cardiac/medical ICU and stepdown patients; generalizability to all wards is imperfect.
- Score does not replace clinical judgment or baseline/serial ECG monitoring when starting a QTc-prolonging agent.