课件：起搏器特殊功能及临床表现.ppt

* * * 三明治现象 * 28ms不是防止极化电位的吗？还需要减少心房输出吗？0.4ms是发放脉冲的时间。而对心房的影响时间不止0.4ms * * * 14 120-90在平缓下降 * 心房失夺获又称阈下夺获，除极能量不能引起心房夺获，但是心房处于应激状态，逆p可以夺获心房。出现PMT的条件：1、存在折返环 2、房室结脱离不应期（AV 延长） 3 心房脱离不应期（PVARP 缩短） * * * * * * If an atrial pace falls within the atriums relative refractory period, an atrial tachycardia may be induced. This can happen if a P wave falls during the PVARP (which will not inhibit the scheduled atrial pace) and then the scheduled atrial pace occurs shortly after the refractory sensed P wave and induces an atrial arrhythmia. 和缓慢性心率失常一样，变时性功能不全的患者无法通过药物得到较好的治疗效果，植入频率适应性起搏器是目前最重要的治疗方法 * * * 电极稳定性，患者心肌状态，药物影响 * * Student Notes Here are the objectives. Instructor Notes * Capture Management and Diagnostic Amplitude modification is as follows: 1. The test Amplitude is set at the last Amplitude result from the previous pacing threshold search or at 0.75 V if no previous search has been done; Pulse Width is set at 1.0 ms. 2. The pacemaker initiates a series of support cycles and test paces to determine whether the Amplitude setting is above or below the patient?ˉs stimulation threshold. 3. If the test Amplitude is above the patient?ˉs threshold, the pacemaker will reduce it by one setting and repeat the test series. The process of reducing the Amplitude setting and retesting continues until a point below the patient?ˉs threshold is found, indicating loss of capture. 4. The pacemaker then increments and retests the Amplitude one setting at a time until the setting is above the patient?ˉs stimulation threshold for three consecutive test series, indicating capture is recovered. The setting at which capture is recovered is called the rheobase approximation. 99年Pace ER波变化探讨 * * * * * This slide details one timing test cycle and the “windows” used by the device to determine if capture was as a result of a test pace, a backup pace, or whether there was loss-of-capture (resulting in a VP). The “expected windows” are dynamically defined in multiples of clock cycles wit