부산대학교 도서관

Background: Increased heart rate (HR) is a strong predictor of unfavorable cardiovascular outcomes, although the mechanisms are still unknown. We hypothesized that increased HR may be associated with, and possibly an early indicator of, subclinical left ventricular (LV) dysfunction when LV ejection fraction is still normal. The present study aimed to investigate the association of resting HR (RHR) and ambulatory HR with global longitudinal strain (GLS) in a sample of the general population.Methods: The study consisted of 549 participants with LV ejection fraction ≥50% who underwent 24-hour ambulatory blood pressure and HR monitoring and 2-dimensional speckle-tracking echocardiography as part of the Cardiac Abnormalities and Brain Lesion (CABL) study. Participants were divided into 3 groups based on RHR and 24-hour HR: HR<60 (low HR), HR 60-79 (normal HR), and HR≥80 beats/min (high HR).Results: Impaired GLS (>-14.7%) was observed in 89 (16.2%) participants. Frequency of impaired GLS was lowest in low, intermediate in normal, and highest in high RHR group (11.5%, 15.1%, and 24.5%, p=0.035: Figure). Increased RHR (adjusted odds ratio [OR] 1.47 per 10 beats/min, p<0.001) and 24-hour HR (adjusted OR 1.42 per 10 beats/min, p=0.018) were associated with impaired GLS independent of cardiovascular risk factors, ambulatory blood pressure and echocardiographic variables. In the high RHR group, significantly higher prevalence of impaired GLS was observed in participants with high 24-hour HR compared to those with normal/low 24-hour HR (34.5% vs. 10%, p=0.006).Conclusions: Increased RHR and ambulatory HR are significantly associated with impaired GLS. This finding may be involved in explaining the higher cardiovascular risk in high HR subjects.