Electrocardiographic PR Interval Duration and Cardiovascular Risk: Results From the Copenhagen ECG Study
Peter Vibe Rasmussen1, Jonas Bille Nielsen1, Morten Wagner Skov1
1Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), Copenhagen, Denmark; Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
Insights
Both short and long PR intervals increase cardiovascular death risk. A prolonged PR interval also elevates heart failure and pacemaker implantation risks, highlighting nonlinear associations.
Area of Science:
- Cardiology
- Electrocardiography
- Public Health
Background:
- Previous studies on PR interval and adverse outcomes have yielded ambiguous results.
- The relationship between PR interval and cardiovascular events may be nonlinear.
Purpose of the Study:
- To investigate the association between PR interval and the risk of all-cause and cardiovascular death, heart failure, and pacemaker implantation.
- To account for potential nonlinear relationships between PR interval and adverse outcomes.
Main Methods:
- A large cohort of 293,111 individuals from Copenhagen with digital electrocardiograms.
- Data linkage with Danish registries for drug use, comorbidities, and outcomes.
- Cox proportional hazards models were used to analyze the association between PR interval and adverse outcomes, with reference to a normal PR interval range.
Main Results:
- Both short (< 125 ms) and long (> 200 ms) PR intervals were associated with increased cardiovascular death risk.
- A long PR interval (> 200 ms) was linked to a higher risk of heart failure.
- Increasing PR interval duration showed a dose-response relationship with pacemaker implantation risk, with the highest risk observed for PR intervals > 200 ms.
Conclusions:
- PR interval duration is significantly associated with the risk of adverse cardiovascular outcomes.
- The identified nonlinear relationships and relatively weak associations may explain previously conflicting findings in the literature.
Background:
Because of ambiguous reports in the literature, we aimed to investigate the association between PR interval and the risk of all-cause and cardiovascular death, heart failure, and pacemaker implantation, allowing for a nonlinear relationship.
Methods:
We included 293,111 individuals, corresponding to one-third of the population in the greater region of Copenhagen. These individuals had a digital electrocardiogram recorded in a general practitioner's core facility from 2001-2011. Data on drug use, comorbidities, and outcomes were collected from Danish registries. We divided the population into 7 groups based on the population PR interval distribution. Cox models were used, with reference to a PR interval between 152 and 161 ms (40th to < 60th percentile).
Results:
During follow-up, we identified 34,783 deaths from all causes, 9867 cardiovascular deaths, 9526 cases of incident heart failure, and 1805 pacemaker implantations. A short PR interval (< 125 ms; hazard ratio [HR], 1.23; 95% confidence interval [CI], 1.08-1.41; P = 0.001) as well as a long PR interval (> 200 ms; HR, 1.23; 95% CI, 1.14-1.32; P < 0.001) was associated with an increased risk of cardiovascular death after multivariable adjustment. A long PR interval conferred an increased risk of heart failure (> 200 ms; HR, 1.31; 95% CI, 1.22-1.42; P < 0.001). An increasing PR interval conferred an increased risk of pacemaker implantation, in a dose-response manner, with the highest risk associated with a PR interval > 200 ms (HR, 3.49; 95% CI, 2.96-4.11; P < 0.001).
Conclusions:
PR interval was significantly associated with the risk of the adverse outcomes investigated. The nonlinear relationships, in combination with relatively weak associations, could contribute to previously reported conflicting results on the subject.
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