起搏器常见故障与处理.pptVIP

CorePace Module 4: Troubleshooting If a pacemaker is oversensing, you will see signals on the marker channel that do not correspond to the ECG pattern. In this example, the pacemaker recorded a ventricular pulse on the marker channel. However, no activity was demonstrated on the ECG strip. Pauses or intervals longer than the programmed lower rate will occur in single chamber systems. Dual chamber systems may show tracking at the upper rate with atrial oversensing. This ECG exhibits oversensing that may be attributed to: Lead insulation failure (a decrease in lead impedance will be seen) Make-and-break fracture A lead connection problem (Note: The information below transitions into the next slide.) Insulation failure梐 common cause of oversensing梠ccurs when myopotentials are detected at the site of the insulation break. Lead fracture is another common cause of oversensing. As the frayed ends of conductor wires 搈ake and break？contact, the pacemaker senses these 搈ake and break？signals, which results in oversensing. Oversensing may also occur if the lead is loose in the connector block. CorePace Module 4: Troubleshooting Interference falls under two categories: Electromagnetic interference (EMI) Skeletal myopotentials (noncardiac signals) Oversensing may occur when EMI signals are incorrectly interpreted as P- orR-waves. Sources of EMI are often found in hospitals and include surgical/therapeutic equipment, such as: Electrocautery Transthoracic defibrillation Lithotripsy RF ablation TENS units MRI is generally contraindicated for pacemaker patients. Exposure to a magnetic field may produce high-rate pacing that results in ventricular fibrillation and may damage the circuitry of the device. Concomitant devices, such as ICDs, should be tested to ensure that oversensing between the two devices does not occur. The most common type of myopotential interference is the inappropriate inhibition of pacing pulses as a result of the sensing of myopotentials. Myopotential over