Journal Article

The Natural History of Primary First-Degree Atrioventricular Heart Block

Tate, Robert B, Mathewson, Francis A.L, Mymin, David, Manfreda, Jure

1986

Overview

The long-term prognosis of first-degree heart block in the absence of organic heart disease has not been clearly defined. We addressed this question in a 30-year longitudinal study of 3983 healthy men. We identified 52 cases that were present on entry into the study and 124 incident cases during follow-up. The incidence rose steadily after age 40 and was 1.13 per 1000 person-years over the entire period. Two thirds of the cases had only moderate prolongation of the PR interval (0.22 to 0.23 second). We compared four age-matched controls with each case for histories of scarlet fever, rheumatic fever, diphtheria, smoking, blood pressure, and body-mass index. No significant differences (P>0.05) were found. Likewise, mortality from all causes did not differ between cases and controls. Although somewhat higher rates of morbidity and mortality from ischemic heart disease were observed in the cases than in the controls, the differences were not significant. Progression to higher grades of heart block occurred in only two cases. In view of the prognostic findings and the rare occurrence of advanced degrees of heart block, we conclude that primary first-degree heart block with moderate PR prolongation is a benign condition. This conclusion may not apply, however, to persons with more marked prolongation of the PR interval, a very rare condition. (N Engl J Med 1986; 315:1183–7.) PHYSICIANS need to understand the importance of abnormalities of the electrocardiogram in \"normal\" persons, because electrocardiographic examinations are often carried out for life-insuranceance or employment purposes, for preoperative evaluation, or as part of a routine annual check-up. The advent of exercise testing and Holter monitoring has greatly increased the detection of abnormalities of rhythm and conduction. One such abnormality, the prognostic implications of which are poorly understood, is primary first-degree atrioventricular heart block. In this paper, the term \"primary\" applies to abnormality of cardiac conduction occurring in the absence of other clinically manifest heart disease. In the largest study of . . .

• Publisher: Massachusetts Medical Society
• Subject: Adult / Age Factors / Aged / Biological and medical sciences / Blood pressure / Cardiac dysrhythmias / Cardiology. Vascular system / Cardiovascular disease / Coronary artery disease / Coronary Disease - mortality / Diphtheria / Diphtheria - complications / Electrocardiography / Follow-Up Studies / Health risk assessment / Heart / Heart Block - etiology / Heart Block - mortality / Heart Block - physiopathology / Heart diseases / Humans / Ischemia / Male / Manitoba / Medical sciences / Middle Aged / Morbidity / Mortality / Prognosis / Rheumatic fever / Rheumatic Fever - complications / Scarlet fever / Scarlet Fever - complications / Smoking