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QT interval instability and QRS interval dispersion in healthy cats and cats with a hypertrophic cardiomyopathy

Rodrigo Franco Bastos1, Giovana Lr Tuleski1, Marlos Gonçalves Sousa1

  • 1Laboratory of Comparative Cardiology, Department of Veterinary Medicine, Federal University of Paraná (UFPR), Curitiba, Brazil.

Journal of Feline Medicine and Surgery
|February 6, 2023
PubMed

Insights

Electrocardiography (ECG) markers, including QT interval variability (STI) and QRS duration (QRSd), can help diagnose hypertrophic cardiomyopathy (HCM) in cats. These ECG findings indicate increased risk and ventricular instability in cats with HCM.

Area of Science:

  • Veterinary Cardiology
  • Cardiac Electrophysiology
  • Feline Medicine

Background:

  • Hypertrophic cardiomyopathy (HCM) is the most prevalent cardiac condition in domestic cats.
  • Electrocardiography (ECG) is crucial for diagnosing HCM and assessing its secondary effects.

Purpose of the Study:

  • To investigate specific ECG markers for diagnosing HCM in cats.
  • To evaluate QT interval variability (total instability [TI], short-term instability [STI], long-term instability [LTI], QT variance [QTv]), mean corrected QT interval (QTa), heart rate-corrected QT interval (QTac), and QRS duration (QRSd) and dispersion (QRSv) in healthy cats versus those with HCM.

Main Methods:

  • ECG data were analyzed from 63 cats (40 controls, 23 with HCM).
  • Calculated parameters included QTa, QTac, QTv, TI, LTI, STI, QRSd, and QRSv.
  • Statistical analysis involved Mann-Whitney U-tests, ROC curves, and logistic regression to assess diagnostic accuracy and risk.

Main Results:

  • Cats with HCM exhibited significantly higher QTa, QTac, QRSd, and STI compared to controls.
  • Specific thresholds (QTa >158.8 ms, QTac >27.4 ms, QRSd >0.045 s) demonstrated high accuracy in detecting HCM.
  • Logistic regression indicated increased risk of HCM with elevated QTa, QTac, and QRSd values.

Conclusions:

  • HCM in cats is associated with increased ventricular instability (STI) and prolonged QT and QRS intervals (QTa, QTac, QRSd).
  • These ECG markers show promise as supplementary tools for screening and identifying HCM in feline patients.
Abstract

Keywords:
QT variabilityRepolarization markersconduction markerselectrocardiography

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