Prognostic significance of prolonged PR interval in the general population

Abstract

AimsProlonged PR interval, or first degree AV block, has been traditionally regarded as a benign electrocardiographic finding in healthy individuals, until recent studies have suggested that it may be associated with increased mortality and morbidity. The aim of this study was to further elucidate clinical and prognostic importance of prolonged PR interval in a large middleaged population with a long follow-up. Methods and resultsWe evaluated 12-lead electrocardiograms of 10 785 individuals aged 30 -59 years (mean age 44 years, 52% males) recorded between 1966 and 1972, and followed the subjects for 30 + 11 years. Prolonged PR interval was defined as PR .200 ms, with further analysis performed using PR ≥220 ms. Main endpoints were all-cause mortality, cardiovascular mortality, and sudden cardiac death, and other endpoints included hospitalizations due to cardiovascular causes. During the baseline examination, prolonged PR interval .200 ms was present in 2.1% of the subjects, but PR interval normalized to ≤200 ms in 30% of these individuals during the follow-up. No increase in mortality or in hospitalizations due to coronary artery disease, heart failure, atrial fibrillation, or stroke was associated with prolonged PR interval (P ¼ non-significant for all endpoints). These results were not changed after multivariate adjustment or in several subanalyses. ConclusionIn the middle-aged general population, prolonged PR interval normalizes in a substantial proportion of subjects during the time course, and it is not associated with an increased risk of all-cause or cardiovascular mortality.--

Long-term outcomes associated with prolonged PR interval in the general Japanese population

“…To the best of our knowledge, this is the first report to study the prognostic significance of prolonged PR interval in Asians. A significant association between the risk of mortality and prolonged PR interval was not found in the National Health and Nutrition Examination Survey (NHANES) [4], a Finnish population-based study [1], and our study. The only significant association reported arises from the Framingham study [3].…”

“…The only significant association reported arises from the Framingham study [3]. The inconsistent results between the Framingham and Finnish populations might be because Framingham participants with prolonged PR interval were almost 10 years older than Finnish participants [1,3]. However, participants with prolonged PR interval in our study had a similar age and sex distribution to those in the Framingham study [3], although the mortality risk related to prolonged PR interval disappeared when confounders (age and sex) were considered.…”

“…Prolonged PR interval can also be accompanied by abnormalities in other parts of the conduction system, including the His-Purkinje system, which is often associated with underlying structural heart disease [1,2]. The association between prolonged PR interval and the risk of mortality has been recently studied in Western general populations yielding inconsistent results [1,3,4].…”

Prolonged PR interval, first-degree heart block and adverse cardiovascular outcomes: a systematic review and meta-analysis

“…Although the prevalence of PR prolongation is relatively rare among the younger population (1% among those age <60 years) it becomes much more common after the age of ≥60 years, with prevalence rising to 6% 3. While it has been suggested that enhanced vagal tone underlies the aetiology of 1°HB in young people, organic heart disease is more prevalent in older subjects and may be linked to myocardial conduction system fibrosis and conduction abnormalities in these groups of patients 4. In patients who are incidentally found to have 1°HB, current expert advice suggests that 1°HB poses little risk, is not associated with significant symptoms and no specific treatment is required 5–7…”

Evolution of Electrocardiographic Abnormalities in Association with Neuromuscular Disorders and Survival in Left Ventricular Hypertrabeculation/Noncompaction

“…3 Whether first-degree AV block in the general population is a nonrelevant finding or an indicator for increased cardiovascular risk is assessed controversially in the epidemiologic literature. 14,15 An increase in the QRS-width >120 ms during follow-up was associated with mortality. Changes in the depth distribution and/or extent of the Purkinje ventricular conduction network in patients with LVHT may lead to altered intraventricular conduction.…”