First-degree atrioventricular block is associated with advanced atrioventricular block, atrial fibrillation and left ventricular dysfunction in patients with hypertension.

Objectives: Clinical significance of first-degree atrioventricular block (AVB) have not been known in patients with hypertension. This study was performed to elucidate long-term prognosis of first-degree AVB in patients with hypertension.

Methods: We included 3816 patients (mean age, 61.0 ± 10.6 years; men, 47.2%) with hypertension. We reviewed their ECGs and measured the PR interval. The patients were divided into two groups: normal PR interval (120 ms ≤ PR ≤200 ms) and first-degree AVB (PR >200 ms). We compared the incidence, cumulative incidence and hazard ratios of advanced AVB, sick sinus syndrome, atrial fibrillation and left ventricular dysfunction between the two groups during the follow-up period.

Results: The prevalence of first-degree AVB in patients with hypertension was 14.3%. The patients were followed up for 9.4 ± 2.4 years. Incidence and cumulative incidence of advanced AVB, atrial fibrillation and left ventricular dysfunction in patients with first-degree AVB were significantly higher than in patients with normal PR interval. By multivariate Cox's regression, patients with first-degree AVB had an increased risk of advanced AVB [hazard ratio 2.77; 95% confidence interval (95% CI) 1.38-5.59; P = 0.004], atrial fibrillation (hazard ratio 2.33; 95% CI 1.84-2.94; P < 0.001) and left ventricular dysfunction (hazard ratio 1.49; 95% CI 1.11-2.00; P = 0.009). However, sick sinus syndrome was not associated with first-degree AVB.

Conclusion: First-degree AVB is an independent risk factor for future development of advanced AVB, atrial fibrillation and left ventricular dysfunction in patients with hypertension.