Association of Prolong PR and QTC Intervals with Cardiovascular Events and Mortality: The Isfahan Cohort Study

This study aimed to assess PR interval and heart rate-corrected QT (QTC) interval prolongation with cardiovascular events (CVEs) and mortality in Iranian adult population. It is a nested case-control study within the Isfahan Cohort Study (ICS). The ICS is an ongoing longitudinal population based study of 6504 adults aged 35 and older and without history of CVEs. PR and QTC interval was assessed with baseline electrocardiogram. CVEs and mortality defined as fatal and non-fatal acute myocardial infarction and stroke, unstable angina and Sudden Cardiac Death (SCD). The odds ratio was calculated by conditional logistic regression. Totally 432 subjects with CVEs and 394 participants free of CVEs in the control group were included in the analysis. There was not association between prolonged PR interval and CVEs, SCD and cardiovascular mortality in crude and all adjusted models. The same results were seen in prolonged QTC interval and CVEs and SCD; but there was significant relationship between prolonged QTC interval and cardiovascular mortality in crude model, 2.98 (95% CI: 1.16-7.66, P = 0.023). However, in adjusted models there was no significant difference. In conclusion, prolonged PR and QTC intervals were not associated with an increased risk of CVEs and mortality in Iranian adult.

Keywords: PR Interval; Heart Rate-Corrected Qt Interval; Cardiovascular Events; Cardiovascular Mortality