醫(yī)學(xué)數(shù)字信號(hào)處理心電(編輯修改稿)
2025-02-02 01:34 本頁面
【文章內(nèi)容簡介】 e ECS for any point on the body surface. 如果選擇了 K個(gè)體表ECS 導(dǎo)聯(lián) [v1(t), v2(t), … vk(t)] ， 且由人體胸廓的物理模型得知了導(dǎo)聯(lián)系數(shù) T (或B） ， 則就可由 ()式求解逆問題并計(jì)算時(shí)變的心臟向量 P 。一旦有了這些偶極分量 ， 則就可用方程 ()解正問題以計(jì)算任意點(diǎn)的 ECS. Genesis of the ECS 心電的起源 Time varying motion of the cardiac vector produces the body surface ECS for one heartbeat with its characteristic P and T waves and QRS plex. 心臟向量的時(shí)變運(yùn)動(dòng)產(chǎn)生體表心電，每搏都有其 特征性的 P、 T 波和 QRS復(fù)合波。 Figure Basic configuration for recording an electrocardiogram. Using electrodes attached to the body, the ECG is recorded with an instrumentation amplifier. (a) Transverse (top) view of a slice of the body showing the heart and lungs. (b) Frontal view showing electrodes connected in an approximate lead II configuration. For the points in time that the vector points toward the electrode connected to the positive terminal of the amplifier, the output ECS will be positivegoing． If it points to the negative electrode， the ECS will be negative． (The following statement is better and more detailed. “If the vector points to the electrode connected to the negative terminal of the amplifier, the ECS will be negative”． ) 在心臟矢量指向的電極連到放大器正端的那些時(shí)間點(diǎn)，輸出的 ECS為正的。若心電向量指向的電極連到放大器負(fù)端，則輸出的 ECS為負(fù)的。 Figure Electrocardiogram (ECG) for one normal heartbeat showing typical amplitudes and time duration for the P, QRS, T waves. Figure Relationship between the spread of cardiac electrical activation represent at various time instants by a summing vector (in the upper frames) and the genesis of the E C S ( i n t h e l o w e r f r a m e s ) . In Figure (a), the slow moving depolarization of the atria which begins at the sinoatrial(SA) node produces the P wave. As Figure (b) shows, the signal is delayed in the atrioventricular (AV) node resulting in an isoelectric region after the P wave, then as the Purkinje system starts delivering the stimulus to the ventricular muscle, the onset of the Q wave occurs. In Figure (c), rapid depolarization of the ventricular muscle is depicted as a large, fastmoving vector which begins producing the R wave. Figure (d) illustrates that the maximal vector represents a point in time when most of the cells are depolarized, giving rise to the peak of the R wave. In Figure (e), the final phase of ventricular depolarization occurs as the excitation spreads toward the base of the ventricles (to t h e t o p in t h e p i c t u re ) g i v i n g r i s e to t h e S w a v e . In Figure (a), the slow moving depolarization of the atria which begins at the sinoatrial(SA) node produces the P wave. As Figure (b) shows, the signal is delayed in the atrioventricular (AV) node resulting in an isoelectric region after the P wave, then as the Purkinje system starts delivering the stimulu
教學(xué)課件相關(guān)推薦
鄂ICP備17016276號(hào)-1