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Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
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Published on: January 16, 2019

Multifactorial QT interval prolongation.

Geneviève Digby1, Jimmy Machaalany, Paul Malik

  • 1Division of Cardiology, Kingston General Hospital, Queen's University, Kingston, Ontario, Canada.

Cardiology Journal
|June 15, 2010
PubMed
Summary
This summary is machine-generated.

Multiple drug interactions and electrolyte imbalances can cause acquired long QT interval, leading to dangerous heart arrhythmias like torsades de pointes. This highlights risks of polypharmacy in patients with predisposing conditions.

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Area of Science:

  • Cardiology
  • Clinical Pharmacology
  • Electrophysiology

Background:

  • Acquired long QT interval is often linked to drug therapy and electrolyte disturbances.
  • Torsades de pointes is a rare but life-threatening ventricular arrhythmia associated with QT prolongation.

Observation:

  • Two cases of multifactorial acquired QT interval prolongation and torsades de pointes are presented.
  • Case 1 involved venlafaxine, amiodarone, domperidone, hypokalemia, and hypomagnesaemia.
  • Case 2 involved quetiapine, citalopram, hydrochlorothiazide, chronic alcohol abuse, and hypokalemia.

Findings:

  • Polypharmacy involving multiple QT-prolonging drugs can significantly increase the risk of acquired long QT interval.
  • Electrolyte imbalances, such as hypokalemia and hypomagnesaemia, exacerbate drug-induced QT prolongation.
  • The combination of multiple risk factors can precipitate torsades de pointes, even if individual factors are not severe.

Implications:

  • Clinicians must be vigilant about potential QT prolongation in patients with polypharmacy and electrolyte disturbances.
  • Careful medication review and electrolyte monitoring are crucial to prevent acquired long QT interval and torsades de pointes.
  • Understanding multifactorial causes is key to managing and preventing this serious cardiac event.