Mitral annular calcification progression and the risk of atrial fibrillation: results from MESA

To determine if progression of mitral annular calcium (MAC) detected by cardiac computed tomography (CT) predicts incident atrial fibrillation (AF).This analysis included 5683 participants (mean age 64 ± 10 years; 52% women; 40% whites; 27% blacks; 21% Hispanics; 12% Chinese-Americans) from the Multi-Ethnic Study of Atherosclerosis. MAC was measured by cardiac CT at baseline and at a follow-up CT scan over a mean time of 2.4 ± 0.84 years. AF was ascertained by review of hospital discharge records and from Medicare claims data through 31 December 2012. Cox regression was used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between MAC progression and AF. Over a median follow-up of 8.6 years, a total of 533 (9.4%) incident AF cases were detected. In a model adjusted for age, sex, race/ethnicity, education, income, baseline MAC, systolic blood pressure, body mass index, diabetes, smoking, total cholesterol, high-density lipoprotein cholesterol, antihypertensive medications, lipid-lowering therapies, and aspirin, any MAC progression (>0/year) was associated with an increased risk for AF (HR = 1.50, 95% CI = 1.20-1.87). Multiplicative interactions were not significant between MAC progression and AF by age (<65 year vs. older), sex, or race/ethnicity (whites vs. non-whites).Important prognostic information regarding AF risk is obtained with follow-up MAC measurement, as the risk for participants with any MAC progression was substantively greater than participants without progression. MAC progression may detect underlying left atrial abnormalities that predispose to AF.