Calcium transient dynamics and the mechanisms of ventricular vulnerability to single premature electrical stimulation in Langendorff-perfused rabbit ventricles

Heart Rhythm : the Official Journal of the Heart Rhythm Society
Hideki HayashiPeng-Sheng Chen

Abstract

Single strong premature electrical stimulation (S(2)) may induce figure-eight reentry. We hypothesize that Ca current-mediated slow-response action potentials (APs) play a key role in the propagation in the central common pathway (CCP) of the reentry. We simultaneously mapped optical membrane potential (V(m)) and intracellular Ca (Ca(i)) transients in isolated Langendorff-perfused rabbit ventricles. Baseline pacing (S(1)) and a cathodal S(2) (40-80 mA) were given at different epicardial sites with a coupling interval of 135 +/- 20 ms. In all 6 hearts, S(2) induced graded responses around the S(2) site. These graded responses propagated locally toward the S(1) site and initiated fast APs from recovered tissues. The wavefront then circled around the refractory tissue near the site of S(2). At the side of S(2) opposite to the S(1), the graded responses prolonged AP duration while the Ca(i) continued to decline, resulting in a Ca(i) sinkhole (an area of low Ca(i)). The Ca(i) in the sinkhole then spontaneously increased, followed by a slow V(m) depolarization with a take-off potential of -40 +/- 3.9 mV, which was confirmed with microelectrode recordings in 3 hearts. These slow-response APs then propagated through CCP to complete a f...Continue Reading

References

Jun 19, 2001·Journal of Cardiovascular Electrophysiology·M A BrayJ P Wikswo
Oct 5, 2001·IEEE Transactions on Bio-medical Engineering·L DingS B Knisley
Jan 6, 2004·American Journal of Physiology. Heart and Circulatory Physiology·Chikaya OmichiJames N Weiss
May 27, 2006·Circulation Research·James N WeissZhilin Qu

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Citations

Aug 5, 2008·American Journal of Physiology. Heart and Circulatory Physiology·Hideki HayashiPeng-Sheng Chen
Feb 9, 2011·Circulation Journal : Official Journal of the Japanese Circulation Society·Boyoung JoungPeng-Sheng Chen
May 7, 2014·Europace : European Pacing, Arrhythmias, and Cardiac Electrophysiology : Journal of the Working Groups on Cardiac Pacing, Arrhythmias, and Cardiac Cellular Electrophysiology of the European Society of Cardiology·Piero Colli FranzoneSimone Scacchi

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