Association between Prolonged PR Intervals and Significant Coronary Artery Disease in Patients with Non‑ST Elevation Myocardial Infarction and Unstable Angina

Objectives: The purpose of this study was to assess the association between a prolonged PR interval and significant coronary artery disease (CAD) in patients who were acutely admitted with unstable angina or non‑ST‑segment elevation myocardial infarction (NSTEMI). Background: Prolongation of the electrocardiographic PR interval occurs frequently in clinical practice. Few studies to date have evaluated the association between prolonged PR intervals and significant CAD in hospitalized patients with NSTEMI and unstable angina. Methodology: PR interval was measured in 205 patients with NSTEMI or unstable angina, and the patients were divided into those with normal (<200 ms) and prolonged PR interval (≥200 ms). We performed echocardiography and coronary angiography within 48–72 h after hospitalization in all patients. Results: A prolonged PR interval (>200 ms) was present in 96 patients (46.8%). This finding was statistically significantly associated with significant CAD (P = 0.024). In addition, these patients had a trend toward higher Gensini scores (P = 0.093) and a higher frequency of left main coronary artery or three‑vessel CAD (P = 0.069). Conclusion: Our study showed that a prolonged PR interval is independently associated with significant CAD in patients with acute coronary syndrome, in contrast with earlier beliefs.