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

Abstract

Objective: First-degree atrioventricular block is frequently encountered in clinical practice and is generally considered a benign process. However, there is emerging evidence that prolonged PR interval may be associated with adverse outcomes. This study aims to determine if prolonged PR interval is associated with adverse cardiovascular outcomes and mortality. Methods:We searched MEDLINE and EMBASE for studies that evaluated clinical outcomes associated with prolonged and normal PR intervals. Relevant studies were pooled using random effects meta-analysis for risk of mortality, cardiovascular mortality, heart failure, coronary heart disease, atrial fibrillation and stroke or transient ischemic attack.Sensitivity analyses were performed considering the population type and use of adjustments.Results: Our search yielded 14 studies that were undertaken between 1972 and 2011 with 400,750 participants. Among the studies that adjusted for potential confounders, the pooled results suggest an increased risk of mortality with prolonged PR interval RR 1.24 95%CI 1.02-1.51, 5 studies. Prolonged PR interval was associated with significant risk of heart failure or left ventricular dysfunction (RR 1.39 95%CI 1.18-1.65, 3 studies) and atrial fibrillation (RR 1.45 95%CI 1.23-1.71, 8 studies) but not cardiovascular mortality, coronary heart disease or myocardial infarction or stroke or TIA. Similar observations were recorded when limited to studies of first-degree heart block. Conclusions:Data from observational studies suggests a possible association between prolonged PR interval and significant increases in atrial fibrillation, heart failure and mortality. Future prospective studies are needed to confirm the relationships reported, consider possible mechanisms and define the optimal monitoring strategy for such patients.

Arrhythmias in Patients ≥80 Years of Age

“…This rise in prevalence of first-degree AV block is thought to be due to age-related and/or pathological fibrosis of the conduction system (17). Although largely considered benign, a prolonged PR interval has been associated with increased AF, left ventricular dysfunction or heart failure, and mortality (19). In a study of patients ≥85 years of age, first-degree AV block as a single electrocardiographic finding was the strongest predictor of mortality (20).…”

First-degree atrioventricular block: risk marker or innocent finding?

“…Consequently, the current meta-analysis on the prognostic significance of prolonged PR interval by Kwok et al in Heart 2 is a welcome addition to the literature. Their analysis was conducted from 14 studies published between 1972 and 2011, the majority in recent years, with >400 000 participants.…”

“…In a relatively young population, incident PR prolongation is likely to be a finding with excellent prognosis 3. In contrast, among older patients with other conduction disturbances or coronary artery disease, first-degree AV block is more likely to reflect more diffuse underlying cardiac pathology, accounting for the association of PR prolongation with mortality and increased risk of atrial fibrillation and heart failure 2. However, in the final analysis, Kwok et al remind us that measurement of the PR interval is an integral part of ECG evaluation, but the astute clinician should interpret this important variable in the context of the individual patient.…”

ECG-ViEW II, a freely accessible electrocardiogram database

“…From July 2012 to July 2016, there were many data requests (approximately 90) from 13 countries in Asia, North America, and Europe (S1 Table). In addition, two papers were published using the previous ECG-ViEW database [11,12]. However, ECG-ViEW contains only QT/QTc data; it does not provide the PR interval, QRS duration, and cardiac axis data.…”