Pacemaker malfunction due to subcutaneous emphysema.

We describe a pacemaker-dependent patient who presented with malfunction two days after implantation of a physiologic dual-chamber pacing system. The malfunction was due to subcutaneous emphysema produced by subclavian venepuncture. Accumulation of air within the generator pocket of the pacemaker resulted in insulation of the unipolar anodal plate and dysfunction of the device.