In a patient with implanted cardiac pacemaker (defibrillator),which of the following investigation is useful to know the position of the misplaced implant ?.

Ans. a. X-ray (Ref Hurst s The Hea 13/e p1050)Hurst's says "Lead dislodgement maybe radiographically visible or it maybe a microdislodgement, where there is no radiographic change in position, but there is significant increase in pacing threshold and/or decline in electrogram amplitude.Lead dislodgement may result in an increasing pacing threshold, failure to capture, or failure to sense. Lead dislodgement maybe radiographically visible or it maybe a microdislodgement, where there is no radiographic change in position, but there is significant increase in pacing threshold and/or decline in electrogram amplitude.