ventricular lead dislodgement

N° 20
Manufacturer Abbott Device PM

77-year-old man implanted with an AccentTM DR pacemaker for carotid sinus syndrome; recording of this tracing the day after implantation.

Graph and trace

The tracing shows a sinus rhythm with a narrow QRS and normal PR interval; sinus atrial activity is sensed both by the atrial channel and the ventricular channel, which suggests a well-positioned atrial lead and a dislodgement of the ventricular lead in the atrial cavity.


This tracing corresponds to an early dislodgement of the ventricular lead which retreated into the atrial cavity, explaining the simultaneous sensing of sinus activity by the 2 channels. This early dislodgement was related to a poor fixation of the lead at the level of the pacemaker pocket. Repositioning the ventricular lead restored normal operation.

Message to remember

When an abnormal tracing is observed in the immediate aftermath of a dual-chamber pacemaker implantation, the diagnosis of lead dislodgement should be evoked when the functioning of a single lead appears abnormal. The diagnosis of inversion of the 2 leads appears more likely when, clearly, the lead connected to the atrium channel senses and/or paces the ventricle and the lead connected to the ventricular channel senses and/or paces the atrium.