Left atrial to ventricular volume ratio and relation to fitness, cardiovascular risk factors and diastolic function in healthy individuals. The HUNT Study

Left atrial (LA) and ventricular (LV) remodeling is thought to be balanced in healthy individuals, and the LA end-systolic volume (LAV) to LV end-diastolic volume (LVEDV) ratio (LA:LV) could help discriminate between pathological and physiological LA enlargement. We aimed to assess LA:LV and its associations with age, sex, and cardiovascular risk factors HbA1C, body mass index (BMI), systolic blood pressure, and peak oxygen uptake (VO2peak). The association to measures of LV diastolic function and filling pressures were compared to LAV and LA reservoir strain. Cardiopulmonary exercise testing and measurement of risk factors ten years apart and echocardiography at follow-up was performed in 1,348 healthy adults (52% women, mean (SD) age 59 (12) years) prospectively included in a large population study. All risk factors were significantly associated with LA:LV in univariate analyses, while BMI and VO2peak was significantly associated with LA:LV in adjusted models. A higher LA:LV was associated with increased odds ratio (OR) of diastolic dysfunction (OR (95% CI) 2.6 (2.1, 3.3)). Measures of LV filling pressures were more closely associated with LA:LV than LAV and LA reservoir strain, but LA reservoir strain was more closely related to some diastolic function measures. In individuals with LAV >34mL/m2 the LA:LV explained 29% of variance in VO2peak (p < 0.001). A higher LA:LV was associated with, and may improve, assessment of diastolic dysfunction and filling pressures. The LA:LV differentiates VO2peak in individuals with enlarged LAV and may have a role in evaluating whether LA enlargement reflects pathology.