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The prevalence and prognosis of third-degree atrioventricular conduction block: the Reykjavik study
E M Kojic1, T Hardarson, N Sigfusson
1Department of Medicine, National University Hospital, Reykjavik, Iceland.
Insights
The prevalence of third-degree atrioventricular block is low in the general population. Most cases are temporary and linked to underlying heart disease, with fewer individuals requiring pacemakers than anticipated.
Area of Science:
- Cardiology
- Epidemiology
Background:
- Previous studies on third-degree atrioventricular block (AVB) primarily focused on hospital patients and specific professional groups.
- Limited data exists on the prevalence and prognostic significance of third-degree AVB in the general population.
Purpose of the Study:
- To determine the prevalence of third-degree atrioventricular block in a representative population sample.
- To assess the prognostic implications of third-degree AVB.
Main Methods:
- Prospective cardiovascular population study (Reykjavik Study) involving 9139 men and 9773 women aged 33-79 years (1967-91).
- Electrocardiograms were recorded and coded using the Minnesota code.
- Prevalence and outcomes of third-degree AVB were analyzed.
Main Results:
- Third-degree atrioventricular block was identified in 11 individuals (0.04% prevalence).
- The condition was temporary in 64% of cases.
- All affected individuals had coexisting heart disease; 55% required a pacemaker.
Conclusions:
- The prevalence of third-degree AVB in the general population is low.
- Third-degree AVB is often temporary and associated with underlying heart disease, which may be a more significant prognostic factor.
- Fewer individuals than expected required pacemaker implantation.
Objectives:
The objectives of this study were to find the prevalence of third-degree atrioventricular block in representative population sample and to estimate its prognostic significance. Most earlier studies have been performed 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 in 1967-91. Electrocardiograms were taken and coded according to the Minnesota code. Third-degree atrioventricular block was found in 11 persons, seven male and four female, an overall prevalence of 0.04%. All of these individuals had signs of dysrhythmia on electrocardiograms taken later, and in addition some other heart disease. The heart block was temporary in seven individuals (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 subjects. 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.