Long-term follow-up of patients with single lead VDD stimulation

The purpose of this study was to assess the long-term results of a single lead VDD pacing system (Phymos MPS) in 85 patients (48 males, 37 females, mean age 74 +/- 9 years). The system, which incorporates two atrial floating electrodes (Phymos 830-S), was implanted for second- or third-degree Mobitz II AV block. The percentage of AV synchronized pacing, the presence of fusion beats due to short AV delay, and the occurrence of supraventricular arrhythmias was evaluated by Holter monitoring at 6-month intervals. Over a mean period of follow-up of 44 months (range 2-56), over 90% of AV synchronized pacing events were noted in 74 patients (87%). The presence of persistent fusion beats was detected in 12 patients (14%). In ten patients the pacemaker was reprogrammed to VVI mode for supraventricular arrhythmias (7 patients, 8.2%) or unsatisfactory atrial sensing (3 patients, 3.5%). One pacemaker was removed for pocket infection and two for battery depletion. These observations support the use of VDD single lead pacing to combine a physiological mode of stimulation with simple implantation techniques.