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  • 學位論文

以拉普拉斯電位為基礎之心內心電圖分析系統

A Laplacian electrogram analysis system

指導教授 : 徐良育
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摘要


瞭解心房纖維性顫動(atrial fibrillation,AF)停止現象的機制對於心房纖維顫動在治療方法上的發展是相當重要的。然而利用單極(unipolar)量測的方式,心電訊號在區域性的活化波形會被遠端的活化波形或是鄰近區域的再極化波所干擾。為了更清楚瞭解AF在發生時及停止時,心電訊號在心房上區域性的表現,本研究利用拉普拉斯(Laplacian)估算將遠端訊號衰減,進而提高心電訊號在區域性的表現。研究中,發展一套計算拉普拉斯電位的工具,利用週邊電極電壓差值的結果,估算中央電極的拉普拉斯電位,並利用小波轉換及動態閥值為基礎自動擷取活化時間,並依據活化時間繪製電位圖、向量圖及時空圖,以觀察電訊號在心房活化時電流傳遞波前的大小及方向。進而將一次活化的向量製作成向量亂度圖並統計繪製成角度分佈直方圖,而活化時間則重建為活化等時圖,利用兩種圖像的表現,觀察心電訊號在AF停止前的變化。 在實驗方面,將開胸狗以電刺激誘發AF,並施打抗心律不整藥物Procainamide使AF停止,以侵入式15×8的電極矩陣擷取實驗數據。八筆AF停止檔案的平均活化週期為128±9.68ms。由分析結果發現,在AF停止前,其活化等時圖的區塊會由原本碎裂的情形聚集成一個大區塊,而AF停止前最後一跳和前面三組AF發生時在區塊的統計上是有差異的。計算前面三組AF發生時和AF停止前最後一跳之等時圖各區塊電極總數目與區塊個數的比例分別為7.09,7.58,9.54及34.98。由向量亂度方佈直方圖可以發現正常竇性訊號其向量角度會集中在90°與-90°,心房纖維性顫動訊號在向量角度分佈上則是分散無集中趨勢。計算AF停止前最後一跳與正常竇性節律的向量亂度角度分佈直方圖的相關度均方根值為0.54,而前面三組AF發生時與正常竇性節律的向量亂度角度分佈直方圖的相關度均方根值為0.24,說明了在AF停止前最後一跳其電訊號的傳遞方向由散亂趨於一致,致使AF的停止。 本研究證實拉普拉斯估算提高了電位在區域性的表現,而拉普拉斯電位探討AF的停止現象得到的結果與實驗的模式相符。

並列摘要


To clarify the mechanism of termination in atrial fibrillation (AF) is important in developing methodology of treatment. Using unipolar measurement system, the local activations in electrogram were interfered by remote activities and/or adjacent repolarizations. Therefore, the improved methodology of Laplacian estimation to remove the remote activities and enhanced local unipolar electrograms was developed to study the local characteristics of AF. This reported software implementation calculates the 2nd moment derivative from adjacent electrical activities. An algorithm based on wavelet transform was used to determine the local activation automatically. The resulting data of Laplacian electrogram was reconstructed into voltage maps (10 frames/activation), the map of vectors for electrical current flow and the activation in time space (TSP) distribution. The phase of vector was tallied into histogram for further study. The data was further analyzed and isochronal maps in cycling length were reconstructed. Records of 8 canines with electrically-induced AF were acquired by 120 unipolar electrodes which arranged in 15×8 matrix on the right atrium epicardium. In studying the termination in AF, 8 canines were received intravenous Procainamide (sodium blocker) infusion. The result showed that the average cycling length for 8 canines was 128±9.68ms. There was significant difference in pattern of activation among segments of electrogram prior to the last activation before termination. The activation cluster in isochronal map became less and the size of cluster was increased toward the termination. The size of cluster was divided by the number of cluster in the same frame in order to generate an index. In examining 3 segments of electrogram (10 activation/segment) prior to last activation before termination, the ratios were 7.09, 7.58, 9.54 and 34.98 respectively. The ratio became higher toward termination. Furthermore, the distribution of vector for electrical current flow were concentrated at 90∘for repolarization and -90∘for depolarization in sinus. In contract, the distribution of vectors was widely dispersed in AF. The correlation of vector orientation of last activation to the sinus is 0.54. However, in comparison, the correlation of the vector orientation in AF to the sinus was 0.24. These results showed that the orientation of electrical current flow was increasing unified toward the termination of AF. The above results indicated that the processes of AF termination were in agreement to the procedure of treatment. This result was made possible by the clean local characteristic electrical activities. That is the Laplacian estimation procedure significantly enhanced the local activity and suppressed adjacent interfering signal. The methodology demonstrated extracted and provided valuable information for AF studies.

並列關鍵字

vector AF isochronal map termination Laplacian estimation

參考文獻


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被引用紀錄


朱湘麟(2006)。利用拉普拉斯電位分析心房纖維性顫動之停止機制〔碩士論文,中原大學〕。華藝線上圖書館。https://doi.org/10.6840%2fCYCU.2006.00466
林昀融(2006)。以獨立成份分析法探討拉普拉斯電位圖〔碩士論文,中原大學〕。華藝線上圖書館。https://doi.org/10.6840%2fCYCU.2006.00457

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