Retrospectively, we studied 66 consecutive patients in whom we implanted an intravenous DDD pacemaker. The indications were: AV block in 52 patients (79%), sick sinus syndrome in 5 patients (7.5%), both AV block and sick sinus syndrome in 4 patients (6%), and other causes in 5 (7.5%). The venous access route was by subclavian punction in 38 cases (57.5%) and by cephalic vein dissection in 28 (42.5%). With a mean follow-up of 16 months, there were complications in 11 patients (17%), in 9 of them, it was necessary a change in pacing mode different to DDD, and was possible to maintain a DDD pacing mode in 2 patients with a minimal reprogramming. The complications were: A) lost of sense and/or atrial capture in 10 patients (3 of them, had also loss of ventricular capture, one had pacemaker-mediated tachycardia, other had diaphragmatic stimulation and other had a severe infection of the pocket), B) atrial fibrillation appeared in another patient. At the implantation time there were significant differences between patients with and without complications on follow-up, the P wave amplitude was 1.86 +/- 0.75 mV in the first group vs. 3.06 +/- 1.52 mV in the latter group, p < 0.005, and the atrial pacing threshold was 1.10 +/- 1.17 microJ in the first group vs. 0.65 +/- 0.66 microJ in the latter group, p < 0.005. We consider that dual chamber stimulation is a well established form of therapy, although, it requires a more laborious implantation and specialized personal for its follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)