Experimental and Theoretical Analysis of Phase Singularity Dynamics in Cardiac Tissue

Bray, Mark-Anthony; Lin, Shien‐Fong; Алиев, Р. Р.; Roth, Bradley J.; Wikswo, John P.

doi:10.1046/j.1540-8167.2001.00716.x

Cited by 128 publications

(116 citation statements)

References 20 publications

Supporting

Mentioning

110

Contrasting

Order By: Relevance

“…To find the PSs, the Vm traces were translated into phase space, where amplitude cycles in the time domain correspond to the loops in phase domain, rotating around a single origin (7,8). To identify the origin, the median line connecting the middle points of amplitude was determined by data detrending.…”

Section: Experimental Preparationmentioning

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

Self Cite

View full text Add to dashboard Cite

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 ...

show abstract

Section: Experimental Preparationmentioning

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

Self Cite

View full text Add to dashboard Cite

show abstract

“…For cumulative PS display (ie, a PS map) over long acquisition intervals (typically 600 frames), PSs were identified by an automated PS tracking algorithm. 8 Type 2 VF was induced either by progressively increasing D600 concentrations (0.1, 0.5, 2.5, and 5.0 mg/L) during baseline VF (protocol IA, nϭ15) or by giving a high concentration (2.5 or 5.0 mg/L) of D600 from the beginning of the experiments (protocol IB, nϭ10). 1 In both protocols IA and IB, D600 was washed out with drug-free Tyrode's solution to induce washout ventricular tachycardia (VT).…”

Section: Protocol I (N‫:)52؍‬ With a Single Cameramentioning

confidence: 99%

Mother Rotors and the Mechanisms of D600-Induced Type 2 Ventricular Fibrillation

Lin

Baher

et al. 2004

Circulation

Self Cite

View full text Add to dashboard Cite

Background-Two types of ventricular fibrillation (VF) have been demonstrated in isolated rabbit hearts during D600 infusion. Type 1 VF is characterized by the presence of multiple, wandering wavelets, whereas type 2 VF shows local spatiotemporal periodicity. We hypothesized that a single mother rotor underlies type 2 VF. Methods and Results-One (protocol I) or 2 (protocol II) cameras were used to map the epicardial ventricular activations in Langendorff-perfused rabbit hearts. Multiple episodes of type 2 VF were induced in 22 hearts by high-concentration (Ն2.5 mg/L) D600 (protocol I). During type 2 VF, a single spiral wave (nϭ19) and/or an epicardial breakthrough pattern (nϭ11) was present in 14 hearts. These spiral waves either slowly drifted or intermittently anchored on the papillary muscle (PM) of the left ventricle. Dominant-frequency (DF) analyses showed that the highest local DF was near the PM (12.5Ϯ1.1 Hz). There was an excellent correlation between the highest local DF of these spiral waves and breakthroughs (11.8Ϯ1.7 Hz) and the DF of simultaneously obtained global pseudo-ECG (11.2Ϯ1.8 Hz, rϭ0.97, PϽ0.0001) during type 2 VF. We also successfully reproduced the major features of type 2 VF by using the Luo-Rudy action-potential model in a simulated, 3-dimensional tissue slab, under conditions of reduced excitability and flat action-potential duration restitution. Conclusions-Either a stationary or a slowly drifting mother rotor can result in type 2 VF. Colocalization of the stationary mother rotors with the PM suggests the importance of underlying anatomic structures in mother rotor formation.

show abstract

“…For cumulative PS display over long acquisition intervals (typically 200 frames), PSs were identified using our recently developed automated PS tracking algorithm. 7 This was compared with a wavebreak tracking algorithm that initially identified the depolarizing front and repolarizing back of the wavelet 10 by detecting adjacent pixels whose values cross the median in either direction. The points where wavelet front and wavelet back meet are identified as wavebreaks (Figure 1).…”

Section: Optical Mapping and Data Processingmentioning

confidence: 99%

“…1,2 New wavelets can either arise from fragmentation of preexisting wavelets 3 or emanate from a stable rotor 4,5 according to the 2 leading hypotheses. Phase singularities (PSs) 6,7 represent sites in which the activation state cannot be determined, surrounded by a continuum of activation states ranging from fully activated to fully recovered. PSs are believed to be crucial in VF: Wavelets are flanked by PSs, and PSs underlie the formation of rotors and wave splitting.…”

mentioning

confidence: 99%

Spatial Distribution of Phase Singularities in Ventricular Fibrillation

2003

Self Cite

View full text Add to dashboard Cite

show abstract

Experimental and Theoretical Analysis of Phase Singularity Dynamics in Cardiac Tissue

Abstract: Topologic charge densities can be calculated easily and efficiently to reveal phase singularity behavior. However, the differences between theoretical and experimental observations of singularity separation distances indicate the need for more sophisticated numerical models.

Cited by 128 publications

References 20 publications

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

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

Mother Rotors and the Mechanisms of D600-Induced Type 2 Ventricular Fibrillation

Spatial Distribution of Phase Singularities in Ventricular Fibrillation

Contact Info

Product

Resources

About