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33rd International Congress on Electrocardiology

International Society of Electrocardiology

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Development Of Hypertension In Shr Is Charaterized By Positive Relation Between Qt Duration And Systolic Blood Pressure

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  • corresponding author presenting/speaker J. Klimas - Department of Pharmacology and Toxicology, Bratislava, Slowakei
  • J. Kyselovic - Department of Pharmacology and Toxicology, Bratislava, Slowakei
  • L. Bacharova - International Laser Center, Bratislava, Slowakei

33rd International Congress on Electrocardiology. Cologne, 28.06.-01.07.2006. Düsseldorf, Köln: German Medical Science; 2007. Doc06ice136

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/ice2006/06ice136.shtml

Published: February 8, 2007

© 2007 Klimas et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

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Question: Increased duration of QT interval in hypertensive subjects is associated with increased left ventricular mass (LVM). However, increase of QT duration could be related also to the changed blood pressure. The aim of this study was to analyse the relationship between QT duration and arterial systolic blood pressure (sBP) and LVM, resp. during the development of hypertension and left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHR).

Methods Used: SHR at the age of 12 and 20 weeks were compared with age-matched Wistar-Kyoto rats (WKY). Tail-cuff method was used for sBP measurement in conscious rats. Frank electrocardiograms were recorded in anaesthetized animals. QT interval duration was evaluated from the beginning of the QRS complex to the end of T wave in either of the simultaneously recorded leads. After recordings, rats were sacrificed and LVM was weighed.

Results: SHR showed a significant increase of sBP (p<0.001) and LVM (p<0.05) between 12 and 20 week. In 12 week old SHR only non-significant tendency to an increase in QT duration was observed, as compared to age matched WKY (WKY12: 82±9 ms and SHR12: 91±17, resp.; NS). Twenty week old SHR showed significantly higher values of QT duration, as compared to age matched WKY and to SHR12 (WKY20: 81±9 ms and SHR20: 98±10 ms, resp.; p<0.05 vs. WKY20 and SHR12, resp.). There was a significant positive correlation between QT duration and sBP in SHR of both age (p<0.01 and p<0.001), but we found a significant positive relationship between QT and LVM only in 12 week old SHR (p<0.05), i.e. at the age, when the QT duration only tended to increase. There was no correlation between QT duration and sBP or LVM in WKY.

Conclusion: SHR in the stage of progression and stabilization of hypertension and LVH showed the progressive increase of QT duration with age. This increase was related to arterial sBP, but not to LVM.

Supported by grant VEGA 1/3406/06 from The Science Grant Agency, Slovak Republic and the grant FaF UK/005/2005 from the Pharmaceutical Faculty of Comenius University, Slovak Republic