QT Prolongation Management Algorithm
Note: This document provides a structured summary of the QT Prolongation Management Algorithm for educational and reference purposes. It is not a substitute for certified ACLS training and adherence to the latest guidelines published by the American Heart Association (AHA) or other relevant governing bodies. Always consult the most current official guidelines.
Measure the corrected QT interval (QTc) on ECG. QTc > 440 ms in men, > 460 ms in women is generally considered prolonged. Higher values indicate greater risk.
Identify congenital Long QT Syndrome, medications (antiarrhythmics, antibiotics, psychotropics), electrolyte abnormalities (hypokalemia, hypomagnesemia, hypocalcemia), bradycardia, heart failure, female sex, recent cardioversion, rapid rate correction.
Assess for symptoms like syncope, palpitations, or seizures, which may indicate Torsades de Pointes (TdP).
Look for polymorphic VT with QRS twisting around the baseline, often preceded by a long QT interval and a T-U wave.
If unstable or sustained TdP: Immediate Defibrillation (not synchronized cardioversion). If stable or intermittent TdP: IV Magnesium Sulfate 1-2 gm over 1-2 min. Consider overdrive pacing if due to bradycardia.
Discontinue offending medications. Correct electrolyte abnormalities (Magnesium, Potassium, Calcium). Treat bradycardia if present.
Consider Beta-blockers (especially for congenital LQTS). Avoid other QT-prolonging drugs. Consider expert consultation.
Continuous ECG monitoring. Repeat ECGs and labs to assess QTc and electrolytes. Monitor for recurrence of TdP.
Patient education on risk factors and medications. Avoidance of QT-prolonging drugs. Genetic testing/consultation for congenital LQTS. Regular follow-up.
