Should you remove an implantable loop recorder after the diagnosis is made?
A 59 year old man was admitted after an episode of syncope. There were no ictal features and no relevant past medical history or family history. Examination was unremarkable. His resting ECG showed first degree heart block. Over the next four months he had multiple normal investigations including 24 hour ECG recording, electroencephalogram, cranial computed tomography, tilt testing, and carotid Doppler ultrasound. During this period he had two further episodes of syncope. He was therefore admitted for insertion of an implantable loop recorder (ILR) (Reveal Plus, Medtronic). That evening he suffered a further syncopal episode, and interrogation of the ILR revealed complete heart block with prolonged pauses (below left). A dual chamber permanent pacing system was implanted above the ILR, which was left in situ. He had no further episodes of syncope following this procedure, but developed episodic palpitations. ECGs demonstrated paroxysmal atrial fibrillation (PAF). Sotalol failed to control the PAF, so flecainide was substituted. The patient continued to suffer occasional palpitations. Interrogation of the ILR revealed episodes of torsade de pointes ventricular tachycardia (below right). Flecainide was therefore discontinued, and his PAF has been successfully controlled with bisoprolol. No further episodes of torsade de pointes have occurred. Generally, the ILR is removed at the time of pacemaker insertion if a bradyarrhythmia is recorded. As the cost of the device is mainly at implantation, there may be a rationale for leaving the ILR in situ after pacemaker insertion to ensure no additional diagnoses are missed.