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

Higher Cumulative Blood Pressure in Midlife Predicts an Increased Risk of Atrial Fibrillation: Evidence From the Atherosclerosis Risk in Communities Study

BACKGROUND

Elevated blood pressure (BP) is reportedly associated with an increased risk of atrial fibrillation (AF). However, the association between cumulative BP exposure in midlife and incident AF in mid-to-late life remains unclear.

METHODS AND RESULTS

Participants enrolled in the ARIC (Atherosclerosis Risk in Communities) study with 4 consecutive BP measurements and no prevalent AF at baseline were included. Cumulative BP was calculated as the area under the curve from visit 1 to visit 4. Incident AF was identified by study visit ECGs, hospital discharge codes, or death certificates. A total of 9892 participants were included (44.6% men and mean age 62.9±5.7 years at visit 4) with 1550 (15.7%) individuals who developed new-onset AF during an average follow-up of 15.4 years. The incidence rates of AF per 1000 person-years across the 4 quartiles of cumulative systolic BP were 7.9, 9.2, 12.5, and 16.9, respectively. After multivariable adjustment, the hazard ratios for incident AF among participants in the highest quartile of cumulative systolic BP, pulse pressure, and mean arterial pressure were 1.48 (95% CI, 1.27-1.72), 1.81 (95% CI, 1.53-2.13), and 1.22 (95% CI, 1.05-1.41), respectively, compared with those in the lowest quartile. The addition of cumulative systolic BP or pulse pressure slightly improved the ability to predict new-onset AF.

CONCLUSIONS

Higher exposure to cumulative systolic BP, pulse pressure, and mean arterial pressure was significantly associated with increased risk of incident AF.

Left Atrial Strain and the Risk of Atrial Arrhythmias From Extended Ambulatory Cardiac Monitoring: MESA

Background Abnormalities in left atrial (LA) function often occur before LA structural changes and clinically identified atrial fibrillation (AF). Little is known about the relationship between LA strain and the risk of subclinical atrial arrhythmias detected from extended ambulatory cardiac monitoring. Methods and Results A total of 1441 participants of MESA (Multi-Ethnic Study of Atherosclerosis) completed speckle-tracking echocardiography and cardiac monitoring during 2016 to 2018 (mean age, 73 years); participants in AF during echocardiography or during the entire cardiac monitoring period were excluded. Absolute values of LA reservoir, booster pump, and conduit strains were measured. We evaluated associations of LA strain with monitor-detected AF, premature atrial contractions, and supraventricular tachycardia. Primary analyses adjusted for demographic variables, blood pressure, diabetes, smoking, and clinical cardiovascular disease. Cardiac monitoring (median, 14 days) detected AF in 3%. Each SD (4.0%) lower (worse) LA booster pump strain was associated with 84% higher risk of monitor-detected AF (95% CI, 30%-162%), 39% higher premature atrial contraction frequency (95% CI, 27%-53%), and 19% higher supraventricular tachycardia frequency (95% CI, 10%-29%). Additional adjustment for NT-proBNP (N-terminal pro-B-type natriuretic peptide), LA volume index, tissue Doppler a' peak velocity, left ventricular ejection fraction, and global longitudinal strain had little impact on associations. Findings were similar for LA reservoir strain and null for LA conduit strain. Conclusions In a multiethnic community-based cohort, impaired LA strain was an important correlate of subclinical atrial arrhythmias, even after adjustment for conventional measures of LA structure and function.