User's Manual

24 – US-ENGLISH
 During atrial fibrillation episode, pause criterion is fixed to 2s to
avoid long bradycardia episodes in switching to DDD mode.
Despite these differences, the data collected on Symphony devices
are applicable to PARADYM RF because the principles of SafeR
operation did not change. The criteria for switching from AAI to DDD
(or vice versa) did not change. The device’s method for evaluating
the presence of AV conduction did not change.
Methods: All patients were implanted with a Symphony Model 2550
dual-chamber rate-responsive pacemaker with SafeR mode. A
variety of marketed atrial and ventricular pacing leads were used.
The pacemaker was programmed and interrogated via bi-directional
telemetry using a Sorin CRM dedicated programmer and a CPR3
programming head.
The study’s routine evaluation consisted of enrollment, pre-discharge
evaluation, and a scheduled follow-up visit at one month. At pre-
discharge, a 24-hour Holter recording was performed and pacemaker
memory was read. At one month, pacemaker memory was read.
Investigators also documented adverse events.
Patients studied: A total of 45 patients from 12 centers had
Symphony 2550 pacemakers with SafeR. Of these, 14 (31 %) were
female and 31 (69 %) were male. Mean patient age (± SD) was 74 ±
9 years.
Primary indications for implant were: 1st degree AV block (11.1 %),
2nd degree AV block (6.7 %), 3rd degree AV block (22.2 %), sinus
node dysfunction (62.2 %) or other (6.7 %).
Effectiveness results: To determine the effectiveness of SafeR
mode, the percentage of ventricular pacing provided over one month
was recorded from pacemaker memory.