P wave recognition and atrial stimulation with fractally XXXX coated VDD single pass leads.

@entity1 @entity3201 @entity955 @entity1353
The bottleneck of VDD systems is the reliable detection of the small atrial signals by a floating atrial electrode. Fractally @entity3201 coated electrodes offer excellent sensing and pacing performance. In this study, the performance of such a floating @entity955 in P wave sensing and synchronous ventricular stimulation was examined. Atrial pacing was also used as a test of atrial wall contact. @entity1 AND METHODS: A fractally @entity3201 coated VDD lead was implanted in 18 @entity1 . In 15 @entity1 it was interfaced with a VDD pacemaker and in 3 @entity1 with a DDD system depending on the P wave amplitude measured acutely (> or = 2 mV). Simultaneous recordings of the surface ECG and pacemaker telemetry were used to analyze P wave amplitudes and AV synchrony in different body positions, and during normal and deep @entity1353 . Additionally, exercise tests based on daily life activities and 24-hour ECG monitoring were performed to test the pacemaker function. RESULTS: During implantation P wave amplitudes were 1.86 mV +/- 1.08 mV (range 0.5-4.9 mV) and during follow-up (6.6 +/- 5.6 weeks) 0.18-3.8 mV. Holter recordings revealed reliable P wave sensing at a sensitivity setting of 0.5 mV (95.5%). P wave sensing was further improved by a higher atrial sensitivity. AV synchronous pacing > or = 99.9% was achieved in all @entity1 . In 7 @entity1 the atrial electrode could be positioned close to the atrial wall enabling atrial stimulation thresholds at an average of 4.3 volts. CONCLUSION: This fractally @entity3201 coated VVD lead allowed consistent and reliable P wave sensing at an atrial sensitivity as low as 0.5 mV in selected @entity1 .
