Natural course of a prolonged pr interval and the relation between pr and incidence of coronary heart disease. A 7‐year follow‐up study of 1832 apparently healthy men aged 40–59 years

Abstract

Summary: During a baseline cardiovascular survey PR was measured in a strictly standardized way in 1832 men aged 40-59 years, free from coronary heart disease (CHD). Of 1758 men still alive, 1585 underwent an identical follow-up study 7 years later. A total of 1570 were in sinus rhythm. The following findings were made: (1) Baseline and follow-up prevalence of a prolonged PR ( 2 0 . 2 2 s) was identical (5.3 vs. 5.4%). (2) Only 60% of restudied men with a prolonged PR also had prolonged PR at follow-up. (3) Only 1 of 98 with a prolonged baseline PR had a more advanced AV block at follow-up, whereas an additional 4 had conditions which might influence the AV node (1 Bechterew's disease and 3 mild aortic valve stenosis). (4) The incidence of all CHD events found during the follow-up study (CHD deaths, myocardial infarction, angina pectons, and pathologic exercise ECGs) was moderately but significantly lower in men with a prolonged PR than among men with a PR 1 0 . 2 1 s. Thus a prolonged PR is rarely an indicator of impending, more severe conduction disturbances; it is mostly a benign, functional find- ing in middle-aged men free from overt heart disease and is not positively associated with CHD. Rather PR may be moderately and inversely associated with latent CHD.

Prognostic implication of baseline PR interval in cardiac resynchronization therapy recipients

“…Indeed, several studies have shown PR prolongation to have negative prognostic implications in the general population. [20][21][22][23] Specifically, in the Framingham cohort there was a 44% increase in risk of all-cause mortality during long-term follow-up for individuals with PR interval 4200ms. These individuals were also more likely to develop AF and HF or to require pacemaker therapy.…”

Prognostic significance of prolonged PR interval in the general population

“…3 Subsequent studies conducted on over 18 000 male civil servants with a 5-year follow-up, 6 and almost 4000 pilots recruited after World War II with a 30-year follow-up 5 could not show any association between prolonged PR interval ≥220 ms and mortality or CAD, although some studies have provided somewhat contradictory evidence on the relation between PR interval and incidence of CAD. 19,20 Only two major community-based studies have looked into the prognostic significance of the first-degree AV block in the general population. The first, conducted in the 1960s in Tecumseh, Michigan, involving 4678 participants, showed no excess incidence of cardiovascular disease or mortality among persons with PR interval ≥220 ms during the 4-year observation period, although PR interval correlated with cardiac abnormalities especially in persons past 60 years of age.…”

Influence of Age and Sex on P-R Interval at Rest and during Maximal Exercise in Apparently Healthy Individuals

“…Erikssen and Otterstad [16] have shown that P-R interval measurements are highly reproducible at rest. During maximal exercise both a merging of T and P waves and muscular disturbances may occur.…”

“…Examples of the measurements at rest and during maximal exercise are presented in figure 1. At rest, this method is highly reproducible using a paper speed of 50 mm/s [ 16], To rest the reproducibility during exercise with the same paper speed, repeated measurements were performed at rest and at 50, 100, and 150W (200 and 250 W for men only). As a parameter for reproducibility we used the error % [17]:…”

“…The P-R interval was measured as described previously [16] from the start of the P wave to the beginning of the QRS complex in that chest-head lead with the most distinct tracing and is presented as the mean of 5 consecutive beats. Examples of the measurements at rest and during maximal exercise are presented in figure 1.…”