Increased Wave Break During Ventricular Fibrillation in the Epicardial Border Zone of Hearts With Healed Myocardial Infarction

Ohara, Toshihiko; K, Ohara; Cao, Ji Min; Lee, Moon Hyoung; Fishbein, Michael C.; Mandel, William J.; Chen, Peng Sheng; Karagueuzian, Hrayr S.

doi:10.1161/01.cir.103.10.1465

Cited by 44 publications

(33 citation statements)

References 35 publications

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“…However, Xie et al 3 demonstrated in a recent computational study using an anatomically realistic model of the heart that even in the presence of anatomic heterogeneities such as regional differences in fiber orientation, the role of APD restitution in the development of VF remained intact, in that steep restitution was necessary for the disintegration of a single spiral wave into multiple wavelets. In agreement with this computermodeling study, Ohara et al 27 demonstrated in a canine model of chronic myocardial infarction that increased wave break in the epicardial border zone of the infarct is compatible with the APD restitution hypothesis. They found that the dynamic APD restitution curve in the epicardial border zone of the infarct had longer DIs over which the slope was Ͼ1.…”

Section: Fixed Versus Dynamic Heterogeneities As a Cause Of Wave Breaksupporting

confidence: 79%

Altered Dynamics of Action Potential Restitution and Alternans in Humans With Structural Heart Disease

Koller

Maier²,

Gelzer³

et al. 2005

Circulation

114

101

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Background-Restitution kinetics and alternans of ventricular action potential duration (APD) have been shown to be important determinants of cardiac electrical stability. In this study, we tested the hypothesis that APD restitution and alternans properties differ between normal and diseased human ventricular myocardium. Methods and Results-Monophasic action potentials were recorded from the right ventricular septum in 24 patients with structural heart disease (SHD) and in 12 patients without SHD. Standard and dynamic restitution relations were constructed by plotting APD as a function of the preceding diastolic interval. The dynamic restitution relation of both groups showed a steeply sloped segment at short diastolic intervals that was associated with the occurrence of APD alternans. Patients with SHD had a wider diastolic interval range over which APD alternans was present (meanϮSEM 68Ϯ11 versus 12Ϯ2 ms) and showed an earlier onset (168Ϯ7 versus 225Ϯ4 bpm) and an increased magnitude (20Ϯ2 versus 11Ϯ2 ms) of APD alternans compared with patients without SHD. The occurrence of APD alternans during induced ventricular tachycardia (6 episodes) and during rapid pacing could be derived from the dynamic restitution function. Conclusions-There are marked differences in the dynamics of APD restitution and alternans in the ventricular myocardium of patients with SHD compared with patients without SHD. These differences may contribute importantly to cardiac electrical instability in diseased human hearts and may represent a promising target for antiarrhythmic substrate modification.

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Section: Fixed Versus Dynamic Heterogeneities As a Cause Of Wave Breaksupporting

confidence: 79%

Altered Dynamics of Action Potential Restitution and Alternans in Humans With Structural Heart Disease

Koller

Maier²,

Gelzer³

et al. 2005

Circulation

114

101

View full text Add to dashboard Cite

show abstract

“…Other parameters are the same as in the original LR1 model (28). At this parameter setting, the baseline conduction velocity is 0.55 m/s, action potential duration (APD) is shortened to 200 ms from 360 ms in the original model, and the APD restitution curve is similar to those measured from animal experiments (17,33). One important consequence of this modification is that spiral wave breakup leading to spatiotemporal chaos or multiple-wavelet fibrillation occurs in homogeneous 2-D tissue with an average cycle length of 103 ms (41,43).…”

Section: Mathematical Modelmentioning

confidence: 99%

Critical mass hypothesis revisited: role of dynamical wave stability in spontaneous termination of cardiac fibrillation

Qu¹

2006

American Journal of Physiology-Heart and Circulatory Physiology

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The tendency of atrial or ventricular fibrillation to terminate spontaneously in finite-sized tissue is known as the critical mass hypothesis. Previous studies have shown that dynamical instabilities play an important role in creating new wave breaks that maintain cardiac fibrillation, but its role in self-termination, in relation to tissue size and geometry, is not well understood. This study used computer simulations of two-and three-dimensional tissue models to investigate qualitatively how, in relation to tissue size and geometry, dynamical instability affects the spontaneous termination of cardiac fibrillation. The major findings are as follows: 1) Dynamical instability promotes wave breaks, maintaining fibrillation, but it also causes the waves to extinguish, facilitating spontaneous termination of fibrillation. The latter effect predominates as dynamical instability increases, so that fibrillation is more likely to self-terminate in a finite-sized tissue. 2) In two-dimensional tissue, the average duration of fibrillation increases exponentially as tissue area increases. In three-dimensional tissue, the average duration of fibrillation decreases initially as tissue thickness increases as a result of thickness-induced instability but then increases after a critical thickness is reached. Therefore, in addition to tissue mass and geometry, dynamical instability is an important factor influencing the maintenance of cardiac fibrillation.

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“…All in vivo recordings have been localized to specific regions in the ventricles. [7][8][9][10][11][12][13] To date, there has been little in vivo, whole-heart analysis performed under pathological conditions known to predispose to VF.…”

mentioning

confidence: 99%

Mechanisms of Ventricular Fibrillation in Canine Models of Congestive Heart Failure and Ischemia Assessed by In Vivo Noncontact Mapping

et al. 2005

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Background-Much of the research performed studying the mechanism of ventricular fibrillation (VF) has been in normal ventricles rather than under a pathological condition predisposing to VF. We hypothesized that different ventricular substrates would alter the mechanism and characteristics of VF. Methods and Results-Three groups of dogs were studied: (1) control (nϭ8), (2) pacing-induced congestive heart failure (nϭ7), and (3) acute ischemia produced by 30 minutes of mid left anterior descending artery ligation (nϭ5). A noncontact mapping catheter (Ensite 3000, ESI) was placed via transseptal into the left ventricle (LV), along with an electrophysiology catheter. A multielectrode basket catheter (EP Technologies) was placed in the right ventricle, along with an electrophysiology catheter. Several episodes of VF were recorded in each animal. In addition to constructing isopotential and isochronal maps of the VF episodes, signals underwent frequency domain analysis as a fast Fourier transform was performed over a 2-second window every 1 second. From the fast Fourier transform, the dominant frequency was determined, and the organization was calculated. In control dogs, meandering, reentrant spiral wave activity was the main feature of the VF. The congestive heart failure group showed evidence of a stable rotor (nϭ3), evidence of a focal source (nϭ3), or no evidence of a driver in the LV (nϭ1). The ischemic group showed evidence of an initial focal mechanism that transitioned into reentry. In the control and ischemic groups, the LV always had higher dominant frequencies than the right ventricle. Conclusions-Different ventricular substrates produced by the different animal models altered the characteristics of VF.Thus, different mechanisms of VF may be present in the LV, depending on the animal model.

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Increased Wave Break During Ventricular Fibrillation in the Epicardial Border Zone of Hearts With Healed Myocardial Infarction

Abstract: A selective increase in wave break and alteration of reentry occur in the EBZ during VF in hearts with healed myocardial infarction. Increased wave break in the EBZ is compatible with the action potential duration restitution hypothesis.

Cited by 44 publications

References 35 publications

Altered Dynamics of Action Potential Restitution and Alternans in Humans With Structural Heart Disease

Altered Dynamics of Action Potential Restitution and Alternans in Humans With Structural Heart Disease

Critical mass hypothesis revisited: role of dynamical wave stability in spontaneous termination of cardiac fibrillation

Mechanisms of Ventricular Fibrillation in Canine Models of Congestive Heart Failure and Ischemia Assessed by In Vivo Noncontact Mapping

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