Comparison between single lead VDD and conventional DDD pacing systems fortreatment of atrio-ventricular block

Retrospective study comparing two groups of patients paced in the same inst itution for atrio-ventricular (AV) block without sinus dysfunction : 100 pa tients (mean age 72 +/- 6 years; range 61 - 83) paced with a conventional D DD system using two leads; 100 patients (mean age 73 +/- 10 years;range 28 - 88) paced with a single lead VDD system. During implantation, mean atrial amplitudes (DDD 2,31 +/- 0,94 my; VDD 2,06 +/- 0,92 my) were not different ; use of sub-clavian venous way was lower in VDD group : 11 % versus 41 % i n DDD group (p < 0,05). During follow-up (50 +/- 16 months for DDD, 38 +/- 13 months for VDD) annual incidence of atrial sensing loss (DDD 0,5 % versu s VDD 0,6 %), annual incidence of paroxystic (DDD 3,1 % versus VDD 2,2 %) a nd permanent (DDD 1,5 % versus VDD 1,3 %) atrial arrhythmias, were not diff erent for the two modes of pacing. Finally, cumulative dual chamber mode su rvival curves did not show any significant differences between the two grou ps of patients at I year (DDD and VDD 100 %), 2 years (DDD 100 %, VDD 98 %) , 3 years (DDD 98 %, VDD 97 %), 4 years (DDD 97 %, VDD 95 %) and 5 years (D DD and VDD 94 %). We conclude that for treatment of AV block without sinus dysfunction, resul ts of VDD single lead pacing and two leads DDD conventional pacing are very close.