[Maintenance of AAI(R) mode at the time of generator replacement]

In isolated sinus node disease single lead atrial stimulation is recommended. However, an inherent risk includes emerging AV node disturbances with serious bradycardia in the follow-up. This possible scenario frequently results in the implantation of an additional ventricular lead.

In this single-centre retrospective study the interval between 1982 and 2007 was analysed. During this period a total of 6,309 antibradycardia pacemakers were implanted for the first time. Ten percent (n=631) of these devices were single lead atrial pacemakers for treatment of the sick sinus syndrome (SSS). In these 26 years 136 pacemaker replacement operations were performed. During this procedure a thorough reevaluation of the stimulation mode was done.

In 80.6% (n=112) AAI(R) was continued, in 10.1% (n=14) the system was upgraded to DDD(R), and in 9.3% the mode was changed to VVI(R). There were no significant differences in the lifetime of the AAI(R) pacemakers up to the time of this operation: 7.9 vs 6.3 vs 7.0 years.

The single lead atrial pacing mode in SSS is mostly safe also in the long term. A premature change of stimulation mode is rarely necessary.