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Arrhythmia or dysrhythmia refers to an abnormal heart rhythm caused by a defect in the heart's conduction system. It can cause the heart to beat irregularly, too quickly, or too slowly, leading to symptoms like chest pain, shortness of breath, and fainting. Factors such as stress, caffeine, alcohol, nicotine, cocaine, certain drugs, congenital defects, diseases, and electrolyte abnormalities can trigger arrhythmias.
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Related Experiment Video

Updated: May 30, 2025

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
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How to correct QT interval after cardiac resynchronisation therapy.

Amin Esmailian1, Colin Machado2, Hui Chen Han3

  • 1Victorian Heart Institute, Monash University, Clayton, VIC, Australia.

Journal of Electrocardiology
|January 25, 2025
PubMed
Summary
This summary is machine-generated.

Different formulas for corrected QT (QTc) intervals yield varying results after Cardiac Resynchronisation Therapy (CRT). The Bogossian-Hodges and Rautaharju-Fredericia combinations offer consistent QTc measurements in heart failure patients.

Keywords:
Bundle branch blockCardiac resynchronisation therapyCorrected QTJT intervalQRS durationQT interval

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Area of Science:

  • Cardiology
  • Biomedical Engineering

Background:

  • QT interval abnormalities are critical in heart failure patients.
  • Cardiac Resynchronisation Therapy (CRT) impacts electrophysiological parameters.
  • Accurate QT interval correction is essential for risk stratification.

Purpose of the Study:

  • To evaluate various QT interval correction formulas post-CRT.
  • To identify reliable methods for calculating corrected QT (QTc) in CRT patients with wide QRS complexes.

Main Methods:

  • Included severe heart failure patients with left bundle branch block undergoing CRT.
  • Measured QT intervals pre- and post-CRT.
  • Applied multiple formulas (Bogossian, Bazett, Hodges, Rautaharju, Fredericia, etc.) for QTc calculation.

Main Results:

  • CRT significantly reduced QRS duration.
  • Bazett's formula showed no significant QTc change post-CRT.
  • Bogossian-Hodges and Rautaharju-Fredericia formulas yielded comparable and consistent QTc intervals.

Conclusions:

  • Formula choice significantly impacts QTc values in CRT patients.
  • Bogossian-Hodges and Rautaharju-Fredericia combinations are recommended for consistent QTc assessment.
  • Further validation of these QTc correction methods is warranted.