{
  "abstract": "Background The PR interval is a ubiquitous parameter available to all clinicians. Studies on associated risk have been conflicting, often limited by sample sizes and one ECG per individual. The study aimed to investigate the association between the PR interval and its temporal changes with cardiac events in a nationwide cohort.Methods Nationwide hospital ECGs were linked with Danish national registries. Associations between index-PR interval and absolute temporal changes in PR interval (ΔPR), and cardiac events were modelled with multivariable cause-specific Cox models.Results A total of 9 020 051 ECGs (n=2 234 492; 53% female) were available, with 1 213 073 patients having >1 ECG. Median follow-up was 7.1 years. Median index-PR interval was 158 ms. PR interval <120 or >200 ms was found in 2.9% and 7.4%, respectively. Prevalence of prolonged PR interval increased with age. Median ΔPR was 10 ms and highest among the oldest. Cox models between the index-PR interval and events showed the following HR patterns: U-shaped for risk of atrial fibrillation/flutter, heart failure and ventricular arrhythmias (HR 1.03–1.24, 1.04–1.11, 1.08–1.16, respectively, p<0.05); stepwise increase at PR interval ≥170 ms for syncope (HR 1.08–1.36, p<0.001); linear increasing at PR intervals >160 ms (HR 1.07–2.11, p<0.05) for high-degree atrioventricular block/cardiac device implantation; J-shaped with moderate and marginal increases among the shortest (HR 1.44, p<0.001) and longest PR intervals (HR 1.03, p<0.001), respectively, for all-cause mortality. Models on ΔPR showed stepwise increases in HR for all events.Conclusion Prevalence of PR prolongation and temporal PR changes increased with age. Short, long and temporal changes in the PR interval were all associated with increased risk of cardiac events and all-cause mortality.",
  "authors": [
    {
      "affiliations": [
        "Department of Cardiology, Copenhagen University Hospital Rigshospitalet Heart Centre, Copenhagen, Denmark"
      ],
      "name": "Chaoqun Zheng"
    },
    {
      "affiliations": [
        "Department of Cardiology, Copenhagen University Hospital Rigshospitalet Heart Centre, Copenhagen, Denmark",
        "Department of Cardiology, Herlev Hospital, Herlev, Denmark"
      ],
      "name": "Rasmus Frosted"
    },
    {
      "affiliations": [
        "Department of Cardiology, Zealand University Hospital Roskilde, Roskilde, Denmark"
      ],
      "name": "Helle Skovmand Bosselmann"
    },
    {
      "affiliations": [
        "Department of Cardiology, Copenhagen University Hospital Rigshospitalet Heart Centre, Copenhagen, Denmark"
      ],
      "name": "Niels Risum"
    },
    {
      "affiliations": [
        "Department of Cardiology, Copenhagen University Hospital Rigshospitalet Heart Centre, Copenhagen, Denmark",
        "Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"
      ],
      "name": "Christian Jøns"
    },
    {
      "affiliations": [
        "Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark"
      ],
      "name": "Christoffer Polcwiartek"
    },
    {
      "affiliations": [
        "Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark",
        "Prehospital Center, Næstved, Denmark"
      ],
      "name": "Helle Collatz Christensen"
    },
    {
      "affiliations": [
        "Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark"
      ],
      "name": "Kristian Kragholm"
    },
    {
      "affiliations": [
        "Department of Cardiology, Nordsjællands Hospital, Hillerød, Denmark"
      ],
      "name": "Mikkel Porsborg Andersen"
    },
    {
      "affiliations": [
        "Health and Science Technology, Aalborg University, Aalborg, Denmark"
      ],
      "name": "Claus Graff"
    },
    {
      "affiliations": [
        "Department of Cardiology, Nordsjællands Hospital, Hillerød, Denmark",
        "Faculty of Public Health, University of Copenhagen, Copenhagen, Denmark"
      ],
      "name": "Christian Torp-Pedersen"
    },
    {
      "affiliations": [
        "Department of Cardiology, Copenhagen University Hospital Rigshospitalet Heart Centre, Copenhagen, Denmark",
        "Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"
      ],
      "name": "Henning Bundgaard"
    },
    {
      "affiliations": [
        "Department of Cardiology, Copenhagen University Hospital Rigshospitalet Heart Centre, Copenhagen, Denmark",
        "Department of Cardiology, Herlev Hospital, Herlev, Denmark",
        "Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"
      ],
      "name": "Alex Hørby Christensen"
    }
  ],
  "title": "Natural history of the PR interval and risk of cardiac events and mortality: a nationwide study",
  "uid": "6cb13b5f-488e-5dcc-b709-327afc9d8188"
}