The prevalence and prognosis of third-degree atrioventricular conduction block: the Reykjavik Study

Objectives. The objectives of this study were to find the prevalence of thi rd-degree atrioventricular block in representative population sample and to estimate its prognostic significance. Most earlier studies have been perfo rmed on hospital patients and some professional groups, Setting and subjects, In the Reykjavik; Study, a prospective cardiovascular population study, 9139 men and 9773 women aged 33-79 years were examined i n 1967-91, Electrocardiograms were taken and coded according to the Minneso ta code. Third-degree atrioventricular brock was found in 11 persons, seven male and four female, an overall prevalence of 0.04%. All of these individ uals had signs of dysrhythmia on electrocardiograms taken later, and in add ition some other heart disease. The heart block was temporary in seven indi viduals (64%): six (55%) needed a pacemaker. Conclusions. The prevalence of third-degree atrioventricular block in this general population was low, The block was temporary in the majority of subj ects. All had some underlying heart disease, which may affect the prognosis more than the heart block. Fewer subjects than expected were found to need a pacemaker.