Short summary

In this study we evaluate 1- year  mortality among ED-patients with normal PR interval (<200ms), with moderate PR prolongation (201ms - 200ms ) and with severe PR prolongation (>220 ms). The evaluation in this study is based on ED data from the period 2012-2014 from two Danish hospitals (University Hospital of Odense and the Hospital of Southwest Jutland, Esbjerg). The aim is to improve knowledge about 1 year mortality of ED patients presenting with PR interval prolongation.

Rationale

The PR interval reflects the conduction time from the sinus node to the ventricles, thereby reflecting the propagation of electrical impulses from the onset of atrial depolarisation to the beginning of ventricular depolarization. On an ECG the PR interval is electrophysiologically defined as the interval from the onset of the P wave to the end of the PR segment. A first degree atrio-ventricular (AV) block is defined as a PR interval >200 ms (1). First degree AV block has a prevalence of 1% among <60 years olds and 6% among people >60 years (2).

Prolongation of the PR interval has been observed in healthy athletes as a result of increased vagal tone. The condition itself has for long been regarded a benign condition, but increasing evidence supports that PR interval prolongation in different populations is a predictor for future atrial fibrillation (AF), pacemaker and ICD implantation, major cardiac events and mortality(2).

This subject is still debated and the clinical consequence of these findings has not been agreed on.  

The prognostic relevance of PR interval prolongation in the acute setting such as in the emergency department (ED) is yet to be determined. 

Cardiac events such as conduction system disease, ischemic diseases and like has a huge morbidity and is an economic burden to the healthcare system(3). Secondary prophylaxis such as closer monitoring of patients presenting with prolonged PR interval may be beneficial economically and may increase overall health. 

Description of the cohort

This is a cohort study of all visits of adult patients (? 18 years) who had an ECG performed in the Emergency Department, Odense University Hospital and the Emergency Department of Southwest Jutland, Esbjerg in the period 2012-2014.

A database including 47. 765 individuals with 74.192 visits with >=1 ECG measured inside -4 to +4 hours. All these visits is established and has passed primary validation. 

The first papers based at this database has been published (4). The database include information linked at person and visit level including visit site, patient identification (anonymized), age, sex, visit date and time, main symptom at arrival, laboratory values (including CRP, leucocytes, creatinine and electrolytes), a wide range of ECG variables based at the first 12 point ECG performed in the patient within 6 hours after arrival to the ED, information regarding previous and following ECGs performed in the patient and stored in the regional ECG server, comorbidity (overall on Charlson Comorbidity index as well as subtypes of comorbidity), discharge diagnosis for the present hospital contact, and death date.

The database is approved by the Danish Data Protection Agency (No. 2008-58-0035, Journal nr. 15/21632) and The Danish Health Authority (No. 3-3013-1031). 

Publications associated with the project

New-onset atrial fibrillation among patients with infection in the emergency department: A multicentre cohort study of one-year stroke risk.

Hansen TG, MScPharm AP, Brandes A, Ekelund U, Jensen HK, Forberg JL, Brabrand M, Lassen AT.

Am J Med. 2019 Aug 9. pii: S0002-9343(19)30599-6. doi: 10.1016/j.amjmed.2019.06.048

Association between QTc prolongation and mortality in patients with suspected poisoning in the emergency department: a transnational propensity score matched cohort study.

Schade Hansen C, Pottegård A, Ekelund U, Kildegaard Jensen H, Lundager Forberg J, Brabrand M, Lassen AT.

BMJ Open. 2018 Jul 7;8(7):e020036.