Lung tumour masked by implanted cardiac device on a chest radiograph

Permanent pacemakers are an established treatment for sino-atrial disease and heart block, whereas implanted cardiac defibrillators are indicated for recurrent life-threatening ventricular arrhythmia. However, they obscure a small area of lung field on any chest radiograph taken after their insertion. We report two patients with permanent cardiac pacemakers and one patient with an implanted cardiac defibrillator who developed tumours within the underlying lung. They all had their lung tumour masked by the cardiac device on a previous chest radiograph taken within the past three years resulting in a missed opportunity for an early diagnosis.