| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Physiology, Charing Cross and Westminster Medical School, London.
1. Alternate long and short action potential durations, or electrical alternans, has only been sporadically observed in ischaemic myocardium in situ. We systematically studied alternans in the latter to characterize the phenomenon, relate it to ventricular arrhythmia and suggest possible mechanisms. 2. Sixteen Landrace pigs were anaesthetized (Azaperone, N2O and O2), ventilated and the hearts exposed. A branch of the left coronary artery was ligated. Left intraventricular and systemic pressures were monitored. Monophasic action potentials were recorded simultaneously with up to five suction electrodes in and around the proposed ischaemia area. 3. A computer measured the duration of every action potential, at several phases of repolarization, throughout the first hour of ischaemia. This allowed the systematic study of the alternans. Measurements during defined stimulus protocols were also made for the construction of electrical restitution curves. 4. Alternans was found in all recordings within the ischaemic area and in two-thirds of those in the 'border' area. There was no alternans in non-ischaemic areas. 5. The alternans, when action potential duration was plotted for every beat, appeared as an oscillation which was pleomorphic. It could be: (a) stable for hundreds of beats; (b) switched or triggered (by one extraneous beat having a different cycle length) between one stable state with high and one with low or absent alternans; (c) damped; (d) undamped to take a crescendo form, sometimes preceding ventricular fibrillation. 6. The alternans in general showed an ill-defined peak incidence between about 200 to 1500 beats after the onset of ischaemia, and a clearer late peak at about 3000 beats. These periods occurred at about 2-7 min and 15-40 min, corresponding to so-called phase 1A and 1B arrhythmia respectively. Only the late peak was seen with triggered alternans. 7. The electrical restitution curve for the action potential duration during ischaemia when compared with curves, constructed with data from non-ischaemic myocardium, showed a progressive depression in plateau, a reduction in magnitude and was flattened at 1 h. However, there was a reversal or reduction in decline at about 15-45 min. 8. We propose that electrical alternans is a distinctive electrophysiological characteristic of ischaemic myocardium which may be causally related to ventricular arrhythmia and fibrillation, and that at least two mechanisms contribute to the alternans: (i) electrical restitution of the action potential and (ii) changes in intracellular calcium cycling.
This article has been cited by other articles:
|
|
 |
|
  Y. G. Wang, A. V. Zima, X. Ji, R. Pabbidi, L. A. Blatter, and S. L. Lipsius Ginsenoside Re suppresses electromechanical alternans in cat and human cardiomyocytes Am J Physiol Heart Circ Physiol, August 1, 2008; 295(2): H851 - H859. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. T. Clusin Mechanisms of calcium transient and action potential alternans in cardiac cells and tissues Am J Physiol Heart Circ Physiol, January 1, 2008; 294(1): H1 - H10. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. L. Kjolbye, M. Dikshteyn, B. C. Eloff, I. Deschenes, and D. S. Rosenbaum Maintenance of intercellular coupling by the antiarrhythmic peptide rotigaptide suppresses arrhythmogenic discordant alternans Am J Physiol Heart Circ Physiol, January 1, 2008; 294(1): H41 - H49. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. D. Wilson and D. S. Rosenbaum Mechanisms of arrythmogenic cardiac alternans Europace, November 1, 2007; 9(suppl_6): vi77 - vi82. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. P. Nash, C. P. Bradley, P. M. Sutton, R. H. Clayton, P. Kallis, M. P. Hayward, D. J. Paterson, and P. Taggart Whole heart action potential duration restitution properties in cardiac patients: a combined clinical and modelling study Exp Physiol, March 1, 2006; 91(2): 339 - 354. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. M. Narayan T-Wave Alternans and the Susceptibility to Ventricular Arrhythmias J. Am. Coll. Cardiol., January 17, 2006; 47(2): 269 - 281. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
O. Bernus, C. W. Zemlin, R. M. Zaritsky, S. F. Mironov, and A. M. Pertsov Alternating conduction in the ischaemic border zone as precursor of reentrant arrhythmias: A simulation study Europace, January 1, 2005; 7(s2): S93 - S104. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. V. Zaitsev, P. K. Guha, F. Sarmast, A. Kolli, O. Berenfeld, A. M. Pertsov, J. R. de Groot, R. Coronel, and J. Jalife Wavebreak Formation During Ventricular Fibrillation in the Isolated, Regionally Ischemic Pig Heart Circ. Res., March 21, 2003; 92(5): 546 - 553. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. A. Armoundas, G. F. Tomaselli, and H. D. Esperer Pathophysiological basis and clinical application of T-wave alternans J. Am. Coll. Cardiol., July 17, 2002; 40(2): 207 - 217. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Babuty and M. J Lab Mechanoelectric contributions to sudden cardiac death Cardiovasc Res, May 1, 2001; 50(2): 270 - 279. [Full Text] [PDF]
|
|
|
|
|
|
F. Xie, Z. Qu, A. Garfinkel, and J. N. Weiss Effects of simulated ischemia on spiral wave stability Am J Physiol Heart Circ Physiol, April 1, 2001; 280(4): H1667 - H1673. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Pastore and D. S. Rosenbaum Role of Structural Barriers in the Mechanism of Alternans-Induced Reentry Circ. Res., December 8, 2000; 87(12): 1157 - 1163. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. L. Koller, M. L. Riccio, and R. F. Gilmour Jr Effects of [K+]o on electrical restitution and activation dynamics during ventricular fibrillation Am J Physiol Heart Circ Physiol, December 1, 2000; 279(6): H2665 - H2672. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. M. Narayan, B. D. Lindsay, and J. M. Smith Demonstration of the Proarrhythmic Preconditioning of Single Premature Extrastimuli by Use of the Magnitude, Phase, and Distribution of Repolarization Alternans Circulation, November 2, 1999; 100(18): 1887 - 1893. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Tachibana, M. Yamaki, I. Kubota, T. Watanabe, S. Yamauchi, and H. Tomoike Intracoronary Flecainide Induces ST Alternans and Reentrant Arrhythmia on Intact Canine Heart : A Role of 4-Aminopyridine–Sensitive Current Circulation, March 30, 1999; 99(12): 1637 - 1643. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Pastore, S. D. Girouard, K. R. Laurita, F. G. Akar, and D. S. Rosenbaum Mechanism Linking T-Wave Alternans to the Genesis of Cardiac Fibrillation Circulation, March 16, 1999; 99(10): 1385 - 1394. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. L. Koller, M. L. Riccio, and R. F. G. Jr. Dynamic restitution of action potential duration during electrical alternans and ventricular fibrillation Am J Physiol Heart Circ Physiol, November 1, 1998; 275(5): H1635 - H1642. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Chinushi, M. Restivo, E. B. Caref, and N. El-Sherif Electrophysiological Basis of Arrhythmogenicity of QT/T Alternans in the Long-QT Syndrome : Tridimensional Analysis of the Kinetics of Cardiac Repolarization Circ. Res., September 21, 1998; 83(6): 614 - 628. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Tachibana, I. Kubota, M. Yamaki, T. Watanabe, and H. Tomoike Discordant S-T alternans contributes to formation of reentry: a possible mechanism of reperfusion arrhythmia Am J Physiol Heart Circ Physiol, July 1, 1998; 275(1): H116 - H121. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Wu and W. T. Clusin Calcium transient alternans in blood-perfused ischemic hearts: observations with fluorescent indicator Fura Red Am J Physiol Heart Circ Physiol, November 1, 1997; 273(5): H2161 - H2169. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Coronel, T. Opthof, P. Taggart, J. Tytgat, and M. Veldkamp Differential electrophysiology of repolarisation from clone to clinic Cardiovasc Res, March 1, 1997; 33(3): 503 - 517. [PDF]
|
|
|
|
|
|
P. Taggart, P. M.I. Sutton, M. R. Boyett, M. Lab, and H. Swanton Human Ventricular Action Potential Duration During Short and Long Cycles: Rapid Modulation by Ischemia Circulation, November 15, 1996; 94(10): 2526 - 2534. [Abstract] [Full Text]
|
|
|
|
|
|
D. M. Roden, R. Lazzara, M. Rosen, P. J. Schwartz, J. Towbin, and G. M. Vincent Multiple Mechanisms in the Long-QT Syndrome: Current Knowledge, Gaps, and Future Directions Circulation, October 15, 1996; 94(8): 1996 - 2012. [Abstract] [Full Text]
|
|
|
|
|
|
D. S. Rubenstein and S. L. Lipsius Premature Beats Elicit a Phase Reversal of Mechanoelectrical Alternans in Cat Ventricular Myocytes : A Possible Mechanism for Reentrant Arrhythmias Circulation, January 1, 1995; 91(1): 201 - 214. [Abstract] [Full Text]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
