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An 82 year old woman with symptomatic severe aortic stenosis underwent aortic valve replacement with a stentless porcine valve. This was complicated by complete heart block, which failed to resolve after six days. Because of atrial fibrillation at the time of implant, a single chamber (VVI-R) pacemaker was chosen. At implant, lead position and pacing parameters were satisfactory. At two month follow up pacing parameters were again satisfactory, but a chest radiograph using the advanced multiple beam equalisation radiography (AMBER) technique demonstrated lead fracture (left). A repeat standard chest radiograph showed an intact lead (right).
With the AMBER system the x ray beam is passed through a modulator to divide it into 21 channels. Each channel has its own microprocessor and detector, and can be adjusted to provide the correct film density. This compensates for attenuation differences in different parts of the chest. The patient’s chest is scanned from bottom to top in 0.8 seconds. The apparent fracture can be explained by the longer exposure time of the AMBER.1 It should not be confused with pseudofracture, which is a well recognised radiographic pattern attributable to a very tight stay suture on the lead.2