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首页> 外文学位 >Spectral analysis of optical maps in isolated rabbit hearts during ventricular fibrillation and spontaneous termination.
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Spectral analysis of optical maps in isolated rabbit hearts during ventricular fibrillation and spontaneous termination.

机译：心室颤动和自发终止过程中离体兔心脏的光学图谱分析。

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摘要

Ventricular fibrillation (VF) is the leading cause of death in the western world. Within a few minutes of onset of VF, irreversible damage to the brain and heart occurs leading to death. The only effective treatment for VF at present is defibrillation and unfortunately it is not always successful. Only 1 in 20 out of hospital VF patients are defibrillated successfully but patients do not survive. Hence, it is crucial to understand the basic mechanism of VF to improve defibrillation efficacy and explore alternative treatment options. An optical mapping technique employs imaging of voltage dependent fluorescent dye to visualize electrical activity in isolated animal hearts allowing the study of electrophysiologic properties during fibrillation.; The N-point fast Fourier transform (FFT) has been widely used to analyze optical map data to study activation rates and patterns during fibrillation. Dominant frequency (DF) was extracted from each pixel of the optical map by peak detection of the frequency spectrum obtained using the N-point FFT method. The values in the DF maps were representative of the rate of activation for the corresponding regions and displayed several domains of uniform DF values with distinct boundaries between the domains. Results indicate that spectral peak detection precision is improved when continuous Fourier transform (CFT) was used rather than the N-point FFT method. Possible errors while using N-point FFT are shown in comparison with CFT. DF maps obtained using CFT revealed nuances that went unnoticed in DF maps obtained using N-point FFT. Specifically, gradients between some DF domains were observed and the conduction pattern along such gradients has not been studied previously. Time-space plots and apparent conduction velocity changes studied along these gradients revealed patterns similar to classic Wenckebach type conduction block. However, the gradient patterns are speculated to be due to a Doppler effect of rotor drift during fibrillation. This drift causes apparent conduction velocity changes and may lead to wavebreak due to wavefront-wavetail interaction and play an important role in maintenance of fibrillation.; Typically VF leads to death unless defibrillated. In rare cases, VF reverts back to normal sinus rhythm spontaneously in humans. However, spontaneous reversion to normal sinus rhythm is commonly observed in small, young animals. (Abstract shortened by UMI.)
机译：室颤（VF）是西方世界主要的死亡原因。在VF发作后的几分钟内，对大脑和心脏的不可逆转的损害会导致死亡。目前对VF唯一有效的治疗方法是除颤，但不幸的是，这种治疗并不总是成功的。住院VF患者中只有20分之1成功除颤，但患者无法存活。因此，至关重要的是要了解VF的基本机制，以提高除颤效果并探索替代治疗方案。光学测绘技术采用电压依赖性荧光染料成像来可视化孤立的动物心脏中的电活动，从而研究原纤维形成过程中的电生理特性。 N点快速傅立叶变换（FFT）已被广泛用于分析光学图数据，以研究原纤化过程中的激活速率和模式。通过使用N点FFT方法获得的频谱的峰值检测，从光学图的每个像素中提取主导频率（DF）。 DF图中的值代表相应区域的激活速率，并显示了均匀DF值的多个域，两个域之间具有明显的边界。结果表明，使用连续傅里叶变换（CFT）而不是N点FFT方法可提高光谱峰值检测精度。与CFT相比，显示了使用N点FFT时可能出现的错误。使用CFT获得的DF映射揭示了细微差别，而使用N点FFT获得的DF映射却没有注意到这些细微差别。具体来说，观察到一些DF域之间的梯度，并且沿此梯度的传导模式以前尚未研究过。沿这些梯度研究的时空图和表观传导速度变化揭示了与经典的温克巴赫型传导阻滞相似的模式。然而，推测梯度图案是由于原纤化期间转子漂移的多普勒效应引起的。这种漂移会引起明显的传导速度变化，并可能由于波前-波尾相互作用而导致破裂，并在维持原纤化中起重要作用。除非进行除颤，否则VF通常会导致死亡。在极少数情况下，VF会自发地恢复为正常的窦性心律。但是，通常在幼小动物中观察到自发性恢复正常窦性心律。 （摘要由UMI缩短。）

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  • 作者

    Joel, Suresh Emmanuel.;

  • 作者单位

    Virginia Commonwealth University.;

  • 授予单位 Virginia Commonwealth University.;
  • 学科 Engineering Biomedical.; Biology Animal Physiology.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 105 p.
  • 总页数 105
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生物医学工程;生理学;
  • 关键词

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