Right atrial appendage versus Bachmann's bundle stimulation: a two-year comparative study of electrical parameters in...

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.

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.

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.

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.