心臟疾病對現代人的健康影響已成為不容忽視的問題。而在常見的心臟疾病中，急性心肌梗塞又具有相對較高的猝死風險。急性心肌梗塞的發生是由於粥狀斑塊破裂，進而阻斷冠狀動脈的血液循環。嚴重者會引發心衰竭甚至死亡。在眾多的診斷方法中，心電圖由於具有非侵入性及連續量測之優點而成為最廣泛的應用。雖然單一導程或三導程之心電圖即具有偵測急性心肌梗塞發作期間ST波段及T波之異常波形變化之能力，但是所能提供的診斷訊息仍嫌不足。若要達到更為精確診斷之目的，則需要十二導程心電圖。 本研究的目標是建構一個可攜的裝置，針對十二導程心電圖作即時的監控。目前，有許多心電圖之即時監測系統：其中絕大多數只提供三個或單一導程的記錄方式；另外也有以軟體方式合成十二導程的心電圖訊號，然而這並非真正的十二導程心電圖，此種量測方式與實際量測之間存在無法避免的誤差。另一方面，若採用十二導程心電圖同時記錄的方法，硬體空間與功率消耗勢必高達單一導程的12倍。因此本系統使用了多工的技術，不僅於硬體空間及功率消耗大幅減少，所需頻寬也可獲得顯著改善。 本研究達成了一個低功率消耗、精巧便於攜帶之十二導程心電圖及時記錄系統。期許本系統的完成能對心臟疾病的高危險群病變之即時監控有所助益。Heart disease has become a non-ignorable threat nowadays. Recently, one of the most common cardiac diseases, acute myocardial infarction (AMI), is becoming seriously because of its high risk. AMI occurs when the atherosclerotic plaque ruptures and blocks one or more coronary arteries. It would lead to heart failure or death. Among the diagnostic tests, electrocardiograph (ECG) is a widely accepted tool since its non-invasive and continuous monitoring. Generally, ST segment/T wave abnormalities, which are considered as the early sign of AMI, could be detected on 1-lead or 3-lead ECG. However, the information that 1-lead of 3-lead ECG could provide is not enough for the purpose of precise diagnosis. In the detection of highly time-dependent cardiac diseases, such as AMI, a 12-lead ECG is necessary. The aim of this study is to develop a portable device for real-time 12-lead ECG recording. At present, there are many systems for real-time ECG monitoring. Most of them afford three or less leads for recording and some of them with synthesized 12-lead ECG. However, a problem of the synthesized 12-lead ECG is that non-avoidable errors would be induced by the approximation in the synthesis process. On the other hand, if we try to record all of the 12-lead waveforms at the same time, the power consumption and the dimension of system will be 12 times of an 1-lead system. Therefore, the technique of multiplexing was applied in our design. Not only the size and power consumption were dramatically reduced, the bandwidth requirement was also decreased accordingly. A portable real-time 12-lead ECG recording system with low power consumption has been developed in this study. By the implementation of this system, we honestly hope that this device could be helpful in real-time monitoring of high-risk cardiac diseases.誌謝………………………………………………………… i錄………………………………………………………… ii目錄……………………………………………………… iv文摘要…………………………………………………… v文摘要…………………………………………………… vi、前言…………………………………………………… 1-1 研究背景與動機……………………………………… 1-2 研究目的……………………………………………… 2、研究方法與系統設計………………………………… 4-1 系統架構……………………………………………… 5-2 威氏中間點產生電路………………………………… 6-3 緩衝放大級…………………………………………… 7-4 多工切換模組………………………………………… 8-4-1 通道選擇元件……………………………………… 8-4-2 放大及濾波電路…………………………………… 9-5 控制單元……………………………………………… 11-6 電源供應電路………………………………………… 12-7 韌體程式設計………………………………………… 13、實驗結果……………………………………………… 16-1 系統外觀……………………………………………… 16-2 印刷電路板製作……………………………………… 17-3 頻率響應……………………………………………… 21-4 輸出波形結果………………………………………… 22、討論與結論…………………………………………… 23-1 多工切換之突波現象………………………………… 23-2 結論…………………………………………………… 24-3 未來展望……………………………………………… 25考文獻…………………………………………………… 26錄一 心電圖基本原理………………………………… 28錄二 十二導程心電圖………………………………… 29amp;#8195
