Distribution of extracellular potassium and its relation to electrophysiologic changes during acute myocardial ischemia in the isolated perfused porcine heart.

Coronel, Ruben; Fiolet, J.W.T.; Wilms‐Schopman, Francien J.G.; Schaapherder, Alexander F.; Johnson, TA; Gettes, L. S.; Janse, Michiel J.

doi:10.1161/01.cir.77.5.1125

Cited by 193 publications

(122 citation statements)

References 41 publications

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“…Results show that arrhythmias in phase 1A are reentrant in 76% of the cases and that the substrate for arrhythmogenesis is provided by dispersions in conduction velocity (CV) and refractoriness resulting mostly from heterogeneities in metabolite and ionic concentrations in the ischemic region. [3][4][5][6] Mechanisms of arrhythmogenesis in phase 1B are less well understood, even though this delayed phase shows more ventricular fibrillation episodes than phase 1A.7…”

Section: Introductionmentioning

confidence: 99%

Reentry in survived subepicardium coupled to depolarized and inexcitable midmyocardium: Insights into arrhythmogenesis in ischemia phase 1B

et al. 2008

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Section: Introductionmentioning

confidence: 99%

Reentry in survived subepicardium coupled to depolarized and inexcitable midmyocardium: Insights into arrhythmogenesis in ischemia phase 1B

et al. 2008

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“…The third phase is characterized by secondary slower increase of [K ϩ ] o (57). The regional ischemia causes a very inhomogeneous [K ϩ ] o distribution, with the highest level of [K ϩ ] o at the center of the ischemic area and a sharply decreased level at the border zone (17,30). This heterogeneity, developing during the first phase of [K ϩ ] o accumulation, can be a source of wave fragmentation and underlie 1a arrhythmias.…”

mentioning

confidence: 99%

Regional increase of extracellular potassium leads to electrical instability and reentry occurrence through the spatial heterogeneity of APD restitution

Sidorov¹,

Uzelac

Wikswo

2011

American Journal of Physiology-Heart and Circulatory Physiology

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Sidorov VY, Uzelac I, Wikswo JP. Regional increase of extracellular potassium leads to electrical instability and reentry occurrence through the spatial heterogeneity of APD restitution. Am J Physiol Heart Circ Physiol 301: H209 -H220, 2011. First published May 2, 2011; doi:10.1152/ajpheart.01141.2010.-The heterogeneities of electrophysiological properties of cardiac tissue are the main factors that control both arrhythmia induction and maintenance. Although the local increase of extracellular potassium ([K ϩ ]o) due to coronary occlusion is a well-established metabolic response to acute ischemia, the role of local [K ϩ ]o heterogeneity in phase 1a arrhythmias has yet to be determined. In this work, we created local [K ϩ ]o heterogeneity and investigated its role in fast pacing response and arrhythmia induction. The left marginal vein of a Langendorff-perfused rabbit heart was cannulated and perfused separately with solutions containing 4, 6, 8, 10, and 12 mM of K ϩ . The fluorescence dye was utilized to map the voltage distribution. We tested stimulation rates, starting from 400 ms down to 120 ms, with steps of 5-50 ms. We found that local [K ϩ ]o heterogeneity causes action potential (AP) alternans, 2:1 conduction block, and wave breaks. The effect of [K ϩ ]o heterogeneity on electrical stability and vulnerability to arrhythmia induction was largest during regional perfusion with 10 mM of K ϩ . We detected three concurrent dynamics: normally propagating activation when excitation waves spread over tissue perfused with normal K ϩ , alternating 2:2 rhythm near the border of [K ϩ ]o heterogeneity, and 2:1 aperiodicity when propagation was within the high [K ϩ ]o area. [K ϩ ]o elevation changed the AP duration (APD) restitution and shifted the restitution curve toward longer diastolic intervals and shorter APD. We conclude that spatial heterogeneity of the APD restitution, created with regional elevation of [K ϩ ]o, can lead to AP instability, 2:1 block, and reentry induction. restitution heterogeneity; regional perfusion; optical mapping THE STATIONARY AND DYNAMIC heterogeneities of electrophysiological properties of cardiac tissue play a key role in the induction and maintenance of cardiac arrhythmias (1,10,16,59). Cardiac tissue heterogeneities increase drastically when acute regional ischemia occurs. The early stage of acute ischemia is characterized by abrupt metabolic and electrophysiological changes in the affected area (11). Among them, the more prominent are increased extracellular potassium ([K ϩ ] o ) (25, 26), decreased creatine phosphate (43, 63), elevated intracellular inorganic phosphate (63), acidosis (27, 46), catecholamine release (39), and partial depolarization of transmembrane potential (V m ) (28,36).Since an early change in V m closely relates to [K ϩ ] o accumulation (34, 60), the K ϩ imbalance is considered to be the major factor affecting excitability and is responsible for slow impulse propagation and induction of reentry (51) Although numerous studies have been devoted to investigation ...

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“…To introduce the heterogeneity produced by acute ischemia, we have simulated three main components: hiperkalemia (increase in the extracellular K + concentration ([K + ] o )), hypoxia (activation of the K[ATP] current) and acidosis (reduction in the availability of Na + and Ca + channels) [15,16].…”

Section: Methodsmentioning

confidence: 99%

Effect of lidocaine in acute ischemic situations: A computer modelling study

Cardona¹,

Sáiz²,

Ferrero³

et al. 2008

2008 Computers in Cardiology

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Distribution of extracellular potassium and its relation to electrophysiologic changes during acute myocardial ischemia in the isolated perfused porcine heart.

Cited by 193 publications

References 41 publications

Reentry in survived subepicardium coupled to depolarized and inexcitable midmyocardium: Insights into arrhythmogenesis in ischemia phase 1B

Reentry in survived subepicardium coupled to depolarized and inexcitable midmyocardium: Insights into arrhythmogenesis in ischemia phase 1B

Regional increase of extracellular potassium leads to electrical instability and reentry occurrence through the spatial heterogeneity of APD restitution

Effect of lidocaine in acute ischemic situations: A computer modelling study

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