100 QUESTIONS IN CARDIOLOGY

80 What do I do if a patient has a pacemaker and

needs cardioversion?

Alistair Slade

Patients with pacemakers often require cardioversion,

particularly with the increasing use of pacing techniques in the

management of paroxysmal atrial fibrillation.

Some centres reprogramme or inactivate pacemakers prior to

cardioversion. The decision regarding this should be made on an

individual basis, depending on the type of pacemaker, reason for

implant, and pacing-dependency.

Patients needing cardioversion should have the paddles

applied in a manner such that the electrical field is remote from

the pacemaker electrical field. In practise the standard apex—

sternum approach is safe with a pacemaker in the left shoulder

region, although anteroposterior paddle positioning can be

utilised. The lowest energy possible should be administered, and

the pacemaker should be checked formally after the procedure as

occasionally the pacemaker may change mode as a consequence of

cardioversion. Efforts should be made to ensure that, during

synchronised shock, the defibrillator is recognising the

ventricular, and not atrial, pacing spike.

Modern systems have increasingly effective protection from

external interference.