The Electrical Mechanical Interference of Implantable Cardiac Devices at Computed Tomography Scanning

Background: X-ray radiation during computed tomography (CT) scanning has been reported to cause electrical mechanical interference (EMI: oversense and partial electrical reset) in implantable cardiac device. It remains elusive whether EMI was occurred by clinical CT scan condition. Purpose: Our purpose is to investigate the association of EMI with the clinical CT scan conditions. Method: Implantable cardiac device (cardiac pacemaker, biventricular pacemaker: CRT-P, biventricular pacemaker with implantable cardioverter defibrillator: CRT-D, Medtronic) with its electrode lead sink in a tank filled with saline. CT (Tohshiba: Aquillion 64) scanned Implantable cardiac device with scan conditions in our hospital. The X-ray radiation level was set at the maximal value of the CT scanner (helical scaning i.e., tube voltage: 120 kV, tube current: 300 mA, scanning interval: 5 mm, helical pitch 53, rotation speed 0.35 sec/rot). Results: CT radiation inhibited the pacing pulses of cardiac pacemakers due to oversense of noise. When CT scanned CRT-P, Partial electrical reset was occurred. When CT scanned CRT-D, CRT-D understood frequent noise as ventricular fibrillation. However, cardioversion was not delivered because CRT-D was suffered from radiation exposure with short duration. Conclusion: EMI in implantable cardiac devices could not be avoided with clinical scan condition. The radiological technologists could take proper care of implantable cardiac devises at the time of CT scan.