Ventricular Fibrillation: New Insights into Mechanisms

Weiss, James N.; Chen, Peng‐Sheng; Wu, Tsu Juey; Siegerman, Carin; Garfinkel, Alan

doi:10.1196/annals.1302.010

Cited by 14 publications

(12 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is well known that infarcts in damaged cardiac tissues from post-myocardial infarction hearts can often pin spiral waves down and keep them for awhile until they lead to a state of fibrillation (12,17,34,(47)(48)(49). Our experimental results explicitly demonstrate that infarcts can be more than just a pinning site: Complex spiral tip dynamics can emerge from such a small set of conduction blocks in an otherwise homogeneous cardiac tissue.…”

Section: Resultsmentioning

confidence: 59%

“…In many cases, these studies are motivated by potential application in understanding and preventing various cardiac arrhythmias (8)(9)(10)(11)(12)(13)(14). Wave activities in a real heart can take a few qualitatively different forms: (i) circular (or pacemaker) waves initiated by pacemakers as in a normal heart, (ii) monomorphic or polymorphic self-sustained spiral waves (an abnormal state that is responsible for some reentrant tachycardia), and (iii) a turbulent jumble of small wavelets that continuously form and break up (a deadly condition known as fibrillation) (15)(16)(17)(18)(19)(20)(21).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Complex-periodic spiral waves in confluent cardiac cell cultures induced by localized inhomogeneities

Hwang

Kim

Lee

2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Spatiotemporal wave activities in excitable heart tissues have long been the subject of numerous studies because they underlie different forms of cardiac arrhythmias. In particular, understanding the dynamics and the instabilities of spiral waves have become very important because they can cause reentrant tachycardia and their subsequent transitions to fibrillation. Although many aspects of cardiac spiral waves have been investigated through experiments and model simulations, their complex properties are far from well understood. Here, we show that intriguing complexperiodic (such as period-2, period-3, period-4, or aperiodic) spiral wave states can arise in monolayer tissues of cardiac cell culture in vitro, and demonstrate that these different dynamic states can coexist with abrupt and spontaneous transitions among them without any change in system parameters; in other words, the medium supports multistability. Based on extensive image data analysis, we have confirmed that these spiral waves are driven by their tips tracing complex orbits whose unusual, meandering shapes are formed by delicate interplay between localized conduction blocks and nonlinear properties of the culture medium.arrhythmia ͉ cardiac spiral waves ͉ complex oscillations

show abstract

Section: Resultsmentioning

confidence: 59%

mentioning

confidence: 99%

Complex-periodic spiral waves in confluent cardiac cell cultures induced by localized inhomogeneities

Hwang

Kim

Lee

2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…In most human and animal studies (for survey, see Weiss et al 43 ), the maximal APD restitution slope is near to or Ͼ1 in at least one of the APD restitution curves published in each study, although other investigators have argued differently. 44 Both steep APD restitution slope and Ca 2ϩ i cycling are potential causes of repolarization alternans, which is a clinical marker of increased risk of sudden cardiac death.…”

Section: Discussionmentioning

confidence: 99%

Action Potential Duration Restitution and Alternans in Rabbit Ventricular Myocytes

Goldhaber

Xie

Duong

et al. 2005

Circulation Research

Self Cite

216

245

View full text Add to dashboard Cite

Abstract-Action potential duration (APD) restitution properties and repolarization alternans are thought to be important arrhythmogenic factors. We investigated the role of intracellular calcium (Ca 2ϩ i ) cycling in regulating APD restitution slope and repolarization (APD) alternans in patch-clamped rabbit ventricular myocytes at 34 to 36°C, using the perforated or ruptured patch clamp techniques with Fura-2-AM to record Ca 2ϩ i . When APD restitution was measured by either the standard extrastimulus (S1S2) method or the dynamic rapid pacing method, the maximum APD restitution slope exceeded 1 by both methods, but was more shallow with the dynamic method. These differences were associated with greater Ca 2ϩ i accumulation during dynamic pacing. The onset of APD alternans occurred at diastolic intervals at which the APD restitution slope was significantly Ͻ1 and was abolished by suppressing sarcoplasmic reticulum (SR) Ca

show abstract

“…Despite significant experimental and theoretical effort to clarify the mechanisms of ATP, it is unclear how a sequence of high-frequency pulses terminates the rotating waves, which are believed to be a cause of tachycardia (38). The conventional explanation is that one of the ATP pulses occurs during the so-called vulnerability window (VW), generating a wave front that rotates in a direction opposite to the existing rotating wave.…”

Section: Discussionmentioning

confidence: 99%

Interaction between spiral and paced waves in cardiac tissue

Agladze¹,

Kay²,

Krinsky³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

Agladze K, Kay MW, Krinsky V, Sarvazyan N. Interaction between spiral and paced waves in cardiac tissue. Am J Physiol Heart Circ Physiol 293: H503-H513, 2007. First published March 23, 2007; doi:10.1152/ajpheart.01060.2006.-For prevention of lethal arrhythmias, patients at risk receive implantable cardioverter-defibrillators, which use high-frequency antitachycardia pacing (ATP) to convert tachycardias to a normal rhythm. One of the suggested ATP mechanisms involves paced-induced drift of rotating waves followed by their collision with the boundary of excitable tissue. This study provides direct experimental evidence of this mechanism. In monolayers of neonatal rat cardiomyocytes in which rotating waves of activity were initiated by premature stimuli, we used the Ca 2ϩ -sensitive indicator fluo 4 to observe propagating wave patterns. The interaction of the spiral tip with a paced wave was then monitored at a high spatial resolution. In the course of the experiments, we observed spiral wave pinning to local heterogeneities within the myocyte layer. High-frequency pacing led, in a majority of cases, to successful termination of spiral activity. Our data show that 1) stable spiral waves in cardiac monolayers tend to be pinned to local heterogeneities or areas of altered conduction, 2) overdrive pacing can shift a rotating wave from its original site, and 3) the wave break, formed as a result of interaction between the spiral tip and a paced wave front, moves by a paced-induced drift mechanism to an area where it may become unstable or collide with a boundary. The data were complemented by numerical simulations, which was used to further analyze experimentally observed behavior. antitachycardia pacing; spiral wave drift; neonatal rat cardiomyocytes ROTATING WAVES OF ACTIVITY have been discovered in many biological, physical, and chemical systems (1,3,21,39), yet these studies, in major part, were inspired by the relevance of this topic to the functioning of the heart (28,31,39). A large body of work during the past four decades using experimental and numerical approaches (for review see Refs. 25 and 38) provide a bulk of the information about the dynamics of rotating waves in heart tissue. The development of potentiometric and Ca 2ϩ -sensitive indicators allowed optical mapping of excitation patterns with a high degree of spatial and temporal resolution (for review see Ref. 14). Thus it became possible not only to directly visualize spiral waves in the heart but to follow the details of their behavior.Another important tool was the development of an in vitro experimental system using confluent cardiomyocyte monolayers. This system has reduced structural complexity compared with the heart per se, which is an advantage when the goal is an understanding of the fundamental properties of wave propagation in cardiac tissue. It has provided a basis for many successful studies of wave propagation at the cellular level (19,30,35), generation of steadily rotating single and multiplearmed spiral waves (8, 15), creation of con...

show abstract

Ventricular Fibrillation: New Insights into Mechanisms

Cited by 14 publications

References 55 publications

Complex-periodic spiral waves in confluent cardiac cell cultures induced by localized inhomogeneities

Complex-periodic spiral waves in confluent cardiac cell cultures induced by localized inhomogeneities

Action Potential Duration Restitution and Alternans in Rabbit Ventricular Myocytes

Interaction between spiral and paced waves in cardiac tissue

Contact Info

Product

Resources

About