Published online before print February 21, 2002, doi: 10.1161/01.RES.0000013403.24495.CC
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on October 4, 2001
Revised on February 8, 2002
Accepted on February 8, 2002
Optical Mapping of Arrhythmias Induced by Strong Electrical Shocks in Myocyte Cultures
Vladimir G. Fast * and Eric R. Cheek
From the Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Ala.
* To whom correspondence should be addressed. E-mail: fast{at}crml.uab.edu.
Strong electrical shocks can induce arrhythmias, which might explain why shocks fail to defibrillate. In this work, the localization of arrhythmia source and the relationship with local changes of transmembrane potential (Vm) were determined in geometrically defined cell cultures using optical mapping technique. Uniform-field shocks with strength (E) of 10 to 50 V/cm were applied across cell strands with width of 0.2 and 0.8 mm. The threshold for arrhythmia induction was dependent on the strand width: in the 0.8- and 0.2-mm strands, arrhythmias were induced at E
20.6±1.8 V/cm (n=8) and E30.3±1.8 V/cm (n=8), respectively. At the same shock strength, the arrhythmia rate and duration were larger in the wider strands. During shocks that induced arrhythmias, the Vm waveforms on the anodal side revealed a positive Vm shift that followed the initial large hyperpolarization and postshock elevation of the diastolic Vm. These Vm changes were absent during failed shocks. To determine the localization of the arrhythmia source, arrhythmias were induced in narrow cell strands containing regions of local expansion. Optical mapping of the first extrabeat with a coupling interval of 315±60 ms revealed that in the majority of cases (9 out of 13) the source of arrhythmias was localized in the areas of shock-induced hyperpolarization. Thus, (1) induction of postshock arrhythmias, their rate, and their duration strongly depend on the tissue structure; (2) arrhythmia induction coincides with the appearance of a positive Vm shift in the areas of hyperpolarization; and (3) the source of postshock arrhythmias is located in the areas of shock-induced hyperpolarization.
Key words: defibrillation • imaging • fluorescent dyes • RH-237
This article has been cited by other articles:
 |
|
 |
|
  L. G. Tereshchenko, M. N. Faddis, B. J. Fetics, K. E. Zelik, I. R. Efimov, and R. D. Berger Transient local injury current in right ventricular electrogram after implantable cardioverter-defibrillator shock predicts heart failure progression. J. Am. Coll. Cardiol., August 25, 2009; 54(9): 822 - 828. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. E. Pollard and R. C. Barr Cardiac microimpedance measurement in two-dimensional models using multisite interstitial stimulation Am J Physiol Heart Circ Physiol, May 1, 2006; 290(5): H1976 - H1987. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. P. Nikolski and I. R. Efimov Electroporation of the heart Europace, January 1, 2005; 7(s2): S146 - S154. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Ashihara and N. A. Trayanova Cell and tissue responses to electric shocks Europace, January 1, 2005; 7(s2): S155 - S165. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 O. F. Sharifov, R. E. Ideker, and V. G. Fast High-resolution optical mapping of intramural virtual electrodes in porcine left ventricular wall Cardiovasc Res, December 1, 2004; 64(3): 448 - 456. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. G. Fast, E. R. Cheek, A. E. Pollard, and R. E. Ideker Effects of Electrical Shocks on Cai2+ and Vm in Myocyte Cultures Circ. Res., June 25, 2004; 94(12): 1589 - 1597. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 O. F. Sharifov and V. G. Fast Intramural Virtual Electrodes in Ventricular Wall: Effects on Epicardial Polarizations Circulation, May 18, 2004; 109(19): 2349 - 2356. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. R. Cheek and V. G. Fast Nonlinear Changes of Transmembrane Potential During Electrical Shocks: Role of Membrane Electroporation Circ. Res., February 6, 2004; 94(2): 208 - 214. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. P. Nikolski, A. T. Sambelashvili, V. I. Krinsky, and I. R. Efimov Effects of electroporation on optically recorded transmembrane potential responses to high-intensity electrical shocks Am J Physiol Heart Circ Physiol, January 1, 2004; 286(1): H412 - H418. [Abstract] [Full Text] [PDF]
|
|