Differences in Left Atrial Size and Function and Supraventricular Ectopy Between Black and White Participants in the ARIC Study

Figure 1. Study sample exclusions flowchart. A, Flow of study participants for hypotheses 1 and 3. B, Flow of study participants for hypothesis 2. AF indicates atrial fibrillation.

Figure 2. Differences in left atrial (LA) size and function between Black and White participants: the Atherosclerosis Risk in Communities study, 2011 to 2013 (n=4344; adjusted for age, sex, education, smoking status, alcohol consumption, body mass index, diabetes, hypertension, coronary heart disease, heart failure, stroke, β‐blockers, and calcium channel blockers). LA parameters were evaluated per 1‐SD increment. Following is the definition of 1‐SD: LA maximum volume index 11.1 mL/m2, LA minimum volume index 7.4 mL/m2, LA reservoir strain 7.7%, LA contractile strain 5.6%, LA conduit strain 5.6%, LA emptying fraction 9.4%, LA passive emptying fraction 10.3%, and LA active emptying fraction 10.6%.

Figure 3. Association of left atrial (LA) size and function with atrial tachycardia (AT) runs per day by race: the Atherosclerosis Risk in Communities study, 2011 to 2017 (adjusted for age, sex, education, smoking status, alcohol consumption, body mass index, diabetes, hypertension, coronary heart disease, heart failure, stroke, β‐blockers, and calcium channel blockers). Inverse probability weighting was used.†LA parameters were evaluated per 1‐SD increment. Following is the definition of 1‐SD: LA maximum volume index 9.8 mL/m2, LA minimum volume index 5.9 mL/m2, LA reservoir strain 6.9%, LA contractile strain 5.2%, LA conduit strain 5.5%, LA emptying fraction 8.2%, LA passive emptying fraction 9.9%, and LA active emptying fraction 9.5%. §AT burden was log‐transformed because of the right‐skew distribution. The ratio of geometric means refers to the exponentiated β coefficient from the linear regression and can be interpreted as a percent difference.

Figure 4. Association of left atrial (LA) size and function with premature atrial contraction runs per hour by race: the Atherosclerosis Risk in Communities study, 2011 to 2017 (adjusted for age, sex, education, smoking status, alcohol consumption, body mass index, diabetes, hypertension, coronary heart disease, heart failure, stroke, β‐blockers, and calcium channel blockers). Inverse probability weighting was used. †LA parameters were evaluated per 1‐SD increment. Following is the definition of 1‐SD: LA maximum volume index 9.8 mL/m2, LA minimum volume index 5.9 mL/m2, LA reservoir strain 6.9%, LA contractile strain 5.2%, LA conduit strain 5.5%, LA emptying fraction 8.2%, LA passive emptying fraction 9.9%, and LA active emptying fraction 9.5%. §Premature atrial contraction burden was log‐transformed because of the right‐skew distribution. The ratio of geometric means refers to the exponentiated β coefficient from the linear regression and can be interpreted as a percent difference.