Long-term outcomes of single-lead VDD pacing were studied retrospectively and partly prospectively. Records were analysed of 81 patients out of 133 in whom a single-lead VDD pacemaker was implanted between January 1993 and December 1997 and who attended a follow-up clinic more than two years after the implant. Forty-eight of them attended a prospective follow-up 54 +/- 15 months after the implant. Sinus rhythm was present in 91.5% of the patients and atrial fibrillation in the remaining 8.5%. A-V synchronous pacing was documented in 91.9 to 94.9% at different follow-up periods; however, an intermittent asynchronous ventricular (VVI) pacing of more than 10% occurred intermittently in 19.1% of the patients. Chronic sensed P-wave amplitude was significantly lower than the implant P-wave amplitude (by 70%) and did not correlate with the implant amplitude. Postural changes (supine, sitting, standing, with normal breathing and during deep inspiration) did not have a significant impact on sensed P-wave amplitude more than four years after the implant. Rate histograms were remarkably stable over the years, with dominant heart rate 70 to 79 beats per minute observed for 25 to 30% of the monitored periods. Single-lead VDD pacing was found to be a reliable method of long-term physiological pacing in patients with heart block who returned for follow-up. Routine testing more than four years after the implant does not require postural manoeuvres.