Right Atrial Appendage Versus Bachmann's Bundle Stimulation: A Two-Year Comparative Study of Electrical Parameters in Myotonic Dystrophy Type-1 Patients

Aim: We performed a two-year follow-up comparative study of long-term electrical parameters between the right atrial appendage (RAA) and Bachmann’s Bundle (BB) stimulation in myotonic dystrophy type 1 (MD1) patients. Methods: Twenty-five MD1 patients (18 men; age: 54 ± 13 years) with no difference in the electrical parameters between the RAA site and the BB region at implantation were randomized into two groups: in group I (13 patients; age: 52 ± 14 years; four women) the atrial lead was placed in the RAA and in group II (12 patients, age: 56 ± 12 years, three women) the lead was placed in the BB region. Measurements of electrical parameters were recorded at follow-up intervals of 6 weeks and then 12 and 24 months postimplant. Results: There was no statistically significant different in P-wave amplitude, pacing threshold, and impedance values between the two groups at 6 weeks. At 24 months follow-up, the intrinsic P-wave amplitude was 2.05 ± 1.45 mV in the RAA group versus 3.28 ± 1.09 mV in the BB group (P < 0.05); the pacing threshold was 1.85 ± 1.8 V in the RAA group versus 0.50 ± 0.39 V in the BB group (P = 0.03); there were no differences in the atrial impedance between the two groups during the follow-up period. Conclusions: In a direct two-year follow-up comparison between the RAA and BB atrial pacing sites, we showed a statistically significant increased pacing threshold and decreased intrinsic P-wave amplitude during RAA stimulation in MD1 patients. (PACE 2009; 32:1191–1196) Bachmann’s bundle, myotonic dystrophy, pacemaker, arrhythmias, heart block, fibrosis, sensing,pacing, impedance, atrial lead