Association of Cumulative Systolic Blood Pressure with Left Atrial Function in the Setting of Normal Left Atrial Size: the Atherosclerosis Risk in Communities (ARIC) Study

Abstract

Lower left atrial (LA) function is associated with increased risk for cardiovascular disease (CVD) events; data on risk factors for impaired LA function are limited. We evaluated the effect of cumulative systolic blood pressure (cSBP) from midlife to older age on LA strain in adults with normal LA size. We included participants in the Atherosclerosis Risk in Communities study with LA strain measured on the Visit 5 echocardiogram (2011-2013), excluding those with atrial fibrillation and LA volume index >34ml/m2. cSBP was calculated from Visit 1 (1987-1989) through Visit 5. Linear regression models were used to evaluate associations between cSBP and LA strain measures. 3,859 participants with mean (SD) age of 75.2 (5.0) years were included in the analysis; 725 (18.8%) Black and 2342 (60.7%) women. After adjusting for demographics, CVD risk factors, heart failure, and coronary heart disease, each 10mmHg higher cSBP was associated with 0.32% (95% CI -0.52%, -0.13%) and 0.37% (95% CI -0.51%, -0.22%) absolute reduction in LA reservoir and conduit strain, respectively. Associations were attenuated after adjustment for left ventricular (LV) systolic and diastolic function and mass (-0.12%; 95% CI, -0.31, 0.06 for reservoir strain and -0.24%; 95% CI -0.38%, -0.10% for conduit strain). In subgroup analyses, the association of cSBP with conduit strain was statistically significant among those with normal LV systolic and diastolic function. Cumulative exposure to elevated blood pressure from midlife to late life was modestly associated with lower LA reservoir and conduit strain in older adults with normal LA size, mostly related to the effect of blood pressure on LV function and mass. However, the association of cSBP and LA conduit strain in subgroups with normal LV function suggests that LA remodeling in response to hypertension occurs before LV dysfunction is detected on echocardiography.