This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
In a patient with implanted cardiac pacemaker (defibrillator),which of the following investigation is useful to know the position of the misplaced implant ?. 
Select and explain. 
A. X-ray, B. CT scan, C. MR1, D. USG
A: X-ray
Answer: A: X-ray 
Explanation: 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.