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Clinical outcome as a function of the PR-interval-there is virtue in moderation: data from the Duke Databank for
Fredrik Holmqvist1, Kevin L Thomas2, Samuel Broderick3
1Clinical Cardiac Electrophysiology, Duke University Medical Center, Durham, NC, USA Duke Clinical Research Institute, Duke University Medical Center, Durham, NC, USA fredrik.holmqvist@duke.edu.
Insights
A shorter PR-interval in coronary heart disease patients is linked to increased mortality and cardiovascular events. Prolonged PR-intervals, however, showed no independent association with poor outcomes in this study.
Area of Science:
- Cardiology
- Electrophysiology
- Clinical Outcomes Research
Background:
- A U-shaped association between PR-interval and atrial fibrillation risk has been noted.
- The relationship between PR-interval duration and mortality in coronary heart disease (CHD) patients is not well understood.
Purpose of the Study:
- To investigate the association between PR-interval duration and major adverse cardiovascular outcomes in patients with established coronary heart disease.
Main Methods:
- Analysis of 9,637 patients in sinus rhythm undergoing coronary angiography with significant coronary artery stenosis.
- Exclusion of patients with arrhythmias, advanced atrioventricular block, or wide QRS duration (>120 ms).
- Statistical adjustment for relevant covariates to assess the risk associated with PR-interval variations.
Main Results:
- A decreasing PR-interval below 162 ms was associated with increased risk for all-cause mortality (HR 1.057), composite of death or stroke (HR 1.047), and composite of cardiovascular death or rehospitalization (HR 1.032).
- No significant association was found between PR-interval values above 162 ms and the studied cardiovascular endpoints.
- The findings were adjusted for relevant covariates.
Conclusions:
- In patients with coronary heart disease, a PR-interval shorter than normal is an independent predictor of increased all-cause mortality and major adverse cardiovascular events.
- Prolonged PR-intervals were not independently associated with adverse outcomes in this cohort.
Aims:
Recently, a U-shaped association between PR-interval and the risk of developing atrial fibrillation was described, with higher risk in patients with long and short PR-intervals. Little is known regarding the association of PR-interval duration and mortality. The objective of the current study was to explore the relationship between PR-interval and major cardiovascular outcomes in patients with known coronary heart disease.
Methods And Results:
Patients in sinus rhythm, undergoing coronary angiography at Duke University Medical Center between 1989 and 2010, who had significant stenosis in at least one native coronary artery, were included. Patients with arrhythmia, second- or third-degree AV-block, QRS > 120 ms were excluded. A total of 9,637 patients were included (median age 63, IQR 55-71 years, 67% men). After adjustment for relevant covariates, the risk of a CV event increased with a decreasing PR-interval (10 ms decrements) for PR-interval values <162 ms (all-cause mortality; HR 1.057, 95% CI 1.019-1.096, P = 0.0030, composite of death or stroke; HR 1.047, 95% CI 1.011-1.085, P = 0.0095 and composite of cardiovascular death or cardiovascular rehospitalization; HR 1.032, 95% CI 1.002-1.063, P = 0.0387). No statistically significant changes in the risk associated with PR-interval for values >162 ms were seen for any of the studied endpoints.
Conclusion:
In patients with coronary heart disease, a prolongation of the PR-interval was not independently associated with poor outcomes, but a PR-interval shorter than normal was associated with increased all-cause mortality and other major cardiovascular events.