gms | German Medical Science

33. Internationale Konferenz für Elektrokardiographie

Internationale Konferenz für Elektrokardiographie

Conduction Velocity Of Murine Left Atrial-Pulmonary Vein Tissues Under Normal And Low Temperature

Meeting Abstract

  • Y.-C. Chen - Dept Biomed Engin, Natl Def Med Ctr, Taipei, Taiwan
  • corresponding author presenting/speaker Y.-J. Lai - Inst Life Sci & Physiol, Natl Def Med Ctr, Taipei, Taiwan
  • C.-I. Lin - Institue Physiol, Natl Def Med Ctr, Taipei, Taiwan
  • S.-L. Chudorodova - Komi Sci Ctr, Ural Div, Syktyvkar, Russia
  • I.-M. Roshchevskaya - Komi Sci Ctr, Ural Div, RAS, Syktyvkar, Russia
  • M.-P. Roshchevsky - Komi Sci Ctr, Ural Div, RAS, Syktyvkar, Russia

33rd International Congress on Electrocardiology. Cologne, 28.06.-01.07.2006. Düsseldorf, Köln: German Medical Science; 2007. Doc06ice116

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter:

Veröffentlicht: 8. Februar 2007

© 2007 Chen et al.
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Question: It has been demonstrated previously in rabbit left atrial-pulmonary vein (LA-PV) cardiomyocytes that high temperatures (40-41 oC) enhanced automaticity, induced triggered activity and shortened action potential (AP) duration thus have an increase in arrhythmogenic activity. The aim of present study was to determine effects of low temperature (25 oC) on conduction velocity (CV) and arrhythmogenic activity in LA-PV tissues obtained from wild type (Xin-alpha+/+) and Xin-alpha-null (Xin-alpha-/-) mice.

Methods used: In LA-PV (5 x ≧ 1.5 mm in size) isolated from 9 Xin-alpha+/+ (16-24 week-old) and 8 age-matched Xin-alpha-/- mice, extracellular recording of cardiac APs were performed with a MED64 system (1.45x1.45 mm in size). To determine CV, distance between recording electrode and site of stimulation was divided by time lag from end of stimulating pulse to peak dV/dt.

Results: At 25 oC, 3 out of 9 Xin-alpha+/+ showed automatic rhythms. All LA-PVs were driven at 300 ms cycle length. The CV of Xin-alpha-/- preparations (11±1 cm/sec) was significantly slower than those of Xin-alpha+/+ (24±3 cm/sec). ACh (0.1 µM) accelerated conduction speed and reduced area of conduction block (defined as % area with a conduction speed reduced to ≦10 cm/sec) only in Xin-alpha-/- LA-PV preparations. Also in Xin-alpha+/+ (but not in Xin-alpha-/-) preparations, isoproterenol (0.1 µM) greatly accelerated conduction and reduced area of block. At 37 oC, the CVs were faster in both wild-type and Xin-alpha-/- preparations (63±2 and 32±7 cm/sec in Xin-alpha+/+ and Xin-alpha-/-, respectively) without obvious arrhythmias.

Conclusion: Results show that in murine LA-PV, low temperature (25 oC) decreased CV and could facilitate onset of reentrant tachyarrhythmias.

(Supported by a Taiwan-Russian Research project NSC 94-2320-B016-040).