Relationship between RR and QT Intervals in Normal and Pacing-induced Heart Failure Dogs

Authors

  • Vudhiporn Limprasutr Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri-Dunant Rd., Bangkok 10330
  • Nakkawee Saengklub Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri-Dunant Rd., Bangkok 10330
  • Suwanakiet Sawangkoon Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri-Dunant Rd., Bangkok 10330 Research Study and Testing of Drug’s Effect Related to Cardiovascular System in Laboratory Animal Research Clusters, Chulalongkorn University, Henri-Dunant Rd., Bangkok 10330
  • Chollada Buranakarl Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri-Dunant Rd., Bangkok 10330
  • Narongsak Chaiyabutr Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri-Dunant Rd., Bangkok 10330
  • Anusak Kijtawornrat Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri-Dunant Rd., Bangkok 10330 1Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri-Dunant Rd., Bangkok 10330

Keywords:

BNP, cardiac performance, dog, heart failure, pacing, QT interval

Abstract

This study was conducted to determine the effects of rapid ventricular pacing on cardiac function and hemodynamics, and to determine the most suitable QTc formula for the effects of alterations in the RR interval on the QT interval of conscious dog with heart failure (HF). Electrocardiograms were acquired from dogs (n=18) at baseline and after rapid ventricular pacing (6, 9, 12 weeks). RR and QT intervals were measured and QTc intervals were calculated using 3 common formulae (Bazett, Fridericia and Van de Water). HF was confirmed by reduced left ventricular fractional shortening (p<0.05), significantly faster heart rate (p<0.001) and significantly changed QT and QTc intervals (p<0.001) when compared to the baseline. This model also demonstrated decreased systolic arterial pressure (p<0.01) and increased BNP (p<0.05). The appropriate regression equations were QT = 152.4+0.08RR for normal dogs and QT = 32.3 (RR) 0.29 for HF dogs. In normal dogs, the Van de Water formula reveals the least dependency of QTc on RR interval. In HF dogs, the Fridericia formula appears to be the best equation to remove the influence of heart rate.

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How to Cite

Limprasutr, V., Saengklub, N., Sawangkoon, S., Buranakarl, C., Chaiyabutr, N., & Kijtawornrat, A. (2014). Relationship between RR and QT Intervals in Normal and Pacing-induced Heart Failure Dogs. The Thai Journal of Veterinary Medicine, 44(1), 31–39. Retrieved from https://he01.tci-thaijo.org/index.php/tjvm/article/view/17312

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Original Articles