This study presents a survey of pacemaker patients followed in a pacemaker clinic. Three hundred and twenty-six patients of mean age 77.7 +/- 9.6 years, 52% female, 75% VVI, 25% dual chamber were analysed. One hundred and forty (43%) were in atrial fibrillation and were older, 80.5 +/- 7.1 years, compared with 75.5 +/- 11.4 years (P = 0.014) for those in sinus rhythm. Temporary pacemaker reprogramming was necessary in 86% in order to determine the abnormal rhythm. Thirty-nine (28%) of those in atrial fibrillation were anticoagulated; 37% were on aspirin; only 10.8% of those in atrial fibrillation who were not anticoagulated had contraindications to this therapy. Prevalence of atrial fibrillation increased with age, whereas that of anticoagulation decreased with age. In conclusion, the majority of pacemaker patients with atrial fibrillation, for whom anticoagulation is indicated, fails to receive it: those caring for these patients are urged to ensure its much wider use.