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Updated: Jul 18, 2026
07:15
Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
Published on: January 16, 2019
[Acquired long QT syndrome: a dominant problem?].
1Service de cardiologie, centre hospitalier du Pays d'Aix, avenue des Tamaris, Aix-en-Provence, France. cbarnay@ch-aix.fr
Annales De Cardiologie Et D'Angeiologie
|December 29, 2006
Summary
QT prolongation, a drug-induced heart rhythm issue, is primarily caused by blocking the potassium current (Ikr). This increases arrhythmia risk, especially Torsades de Pointes, influenced by patient factors and drug metabolism.
Area of Science:
- Pharmacology
- Cardiology
- Electrophysiology
Context:
- QT prolongation is a significant pharmacologic adverse effect.
- It is primarily linked to the blockade of the outward potassium current (Ikr).
- This blockade leads to repolarization prolongation, potentially causing early afterdepolarizations and re-entrant arrhythmias like Torsades de Pointes.
Purpose:
- To explain the mechanisms behind QT prolongation and Torsades de Pointes.
- To highlight the concept of "repolarization reserve" and its variability.
- To discuss various risk factors and drug-related influences on QT prolongation.
Summary:
- Drug-induced QT prolongation results from Ikr current blockade, increasing arrhythmia risk.
- The "repolarization reserve" concept explains individual susceptibility, influenced by pathologic, genetic, and drug metabolism factors (Cytochrome P450).
- Risk factors include bradycardia, electrolyte disturbances, cardiac/neurologic conditions, and drug interactions; diagnosis is via ECG, treatment involves magnesium and heart rate acceleration.
Impact:
- Enhances understanding of drug-induced arrhythmias and their management.
- Informs clinical practice regarding patient risk stratification and drug selection.
- Contributes to drug safety monitoring and development by identifying potential risks early.
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