[20086320]
The patient's dual chamber medtronic pacemaker was set to demand pacing only mode (vvi) at rate of 40 beats per minute during a procedure using stereotaxis magnetic navigation system (mns). When the mns system was moved into navigate position, the pacemaker went into "magnet mode" (voo) asynchronous pacing at 85 beats per minute. To prevent complications from inappropriate pacing, the output was decreased from 2. 0 v to 0. 5 v (to intentionally lose capture and prevent pacing). During first application of radio frequency (rf) ablation, ecg morphology changed to what appeared to be paced beats at about 130 beats per minute at higher output. When rf ablation was terminated, the device would stop pacing and the patient's underlying tachycardia at 145 beats per minute was seen on ecg. The phenomenon was repeatedly reproduced with rf application. Grounding pad location was moved from left flank to left thigh, which intermittently resolved the issue. Medtronic rep on site was consulted, and medtronic engineer called by telephone, but no clear cause was identified. Medtronic rep arrived in room to perform device interrogation once the mns system was moved to stowed position. Error message on device indicated it had gone to reset which returned device to the default factory settings of ddd (dual-chamber pacing) 60-130, output of 3. 5 v. Patient's low threshold (~1. 0v) allowed max tracking pacing at 130 beats per minute to capture, and her underlying tachycardia did not require pacing when off rf. Had the patient been pacemaker dependent with a threshold above 3. 5v, no pacing or lack-of-capture and asystole would have occurred. Conversely, had the patient had heart failure or poor cardiac function, the rapid ventricular pacing at 130 beats per minute may have caused hemodynamic collapse. Therefore, it was felt this should be reported as a significant event with potential to cause harm. The pacemaker is still implanted and the patient had a good outcome. ======================manufacturer response for carto 3 rmt electroanatomic mapping system, eo medelctrophysiology recording system, xper hemodynamic recording system, zoll m series defibrillator, siemens artis zee fluoro system, stereotaxis/niobe remote magnetic navigation system. , medtronic dual chamber pacemaker (per site reporter)======================medtronic rep here during procedure. Called technology department.
Patient Sequence No: 1, Text Type: D, B5