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    Patent Pending

    Tisdale Risk Score for QT Prolongation

    Predicts risk of QT prolongation greater than 500 msec in hospitalized patients.

    IMPORTANT

    Launched during COVID-19 crisis. COVID-19 Resource Center.

    This score was derived and internally validated for hospitalized patients, and may not predict outpatient risk of QT prolongation as accurately (but has not been studied in this population).

    When to Use
    Pearls/Pitfalls
    Why Use

    Many hospitalized patients are at increased risk of QT prolongation due to medical conditions they are facing (myocardial infarction, sepsis, heart failure for example), as well as medications they may be prescribed in order to treat these conditions (antibiotics, antivirals, antifungals, or anti-arrhythmics, for example) or continue outpatient medications (like psychotropic medications, methadone, or tamoxifen, for example). This simple score can estimate risk of QT prolongation for a physician or pharmacist managing a patient in the hospital.

    • There are many known factors that increase the risk of QT prolongation; the ones included in this score were found to be the most predictive, but others should not be ignored. Some of the other common risks include:

    • CredibleMeds.org also provides a comprehensive list of drugs that may cause QT prolongation.

    • Drug-drug interactions should always be considered when prescribing multiple medications; this score does not include pharmacokinetic drug interactions.

    • This score also does not consider dosing adjustments for renally-eliminated drugs.

    • Clinicians should always try to avoid QT-prolonging medications when possible.

    • Maintaining normal electrolyte levels can help reduce the risk of QT prolongation as well.

    • Patients with very poor ejection fractions (<20%) are particularly high risk for QT prolongation.

    QT interval prolongation increases the risk of Torsade de pointes (TdP), a type of polymorphic ventricular tachycardia which is life-threatening and often fatal.

    No
    0
    Yes
    +1
    Male
    0
    Female
    +1
    No
    0
    Yes
    +1
    No
    0
    Yes
    +2
    No
    0
    Yes
    +2
    No
    0
    Yes
    +2
    No
    0
    Yes
    +3
    No
    0
    Yes
    +3
    None
    0
    1 QTc-prolonging drug
    +3
    ≥2 QTc-prolonging drugs
    +6
    Confirmed positive
    Suspected
    Unlikely
    Confirmed negative

    Result:

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    Next Steps
    Evidence
    Creator Insights
    Dr. James E. Tisdale

    About the Creator

    James E. Tisdale, PharmD, is a researcher and professor of pharmacy specializing in cardiovascular pharmacotherapy at Purdue University in West Lafayette, IN. Dr. Tisdale’s primary research is focused on the mechanisms, risk factors, and management of drug-induced arrhythmias.

    To view Dr. James E. Tisdale's publications, visit PubMed

    Are you Dr. James E. Tisdale? Send us a message to review your photo and bio, and find out how to submit Creator Insights!
    MDCalc loves calculator creators – researchers who, through intelligent and often complex methods, discover tools that describe scientific facts that can then be applied in practice. These are real scientific discoveries about the nature of the human body, which can be invaluable to physicians taking care of patients.
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