Abstract 5159: Height is the Preferred Index for Left Atrial Volume Measurement in Overweight and Obese Adults
Left atrial enlargement (LAE) is currently identified by left atrial volume (LAV) normalized by body surface area (BSA). We hypothesized that indexing LAV to BSA (LAV/BSA) in obese individuals would overcorrect for LAV due to the contribution of adiposity to BSA. In contrast, LAV normalized for height (Ht) or Ht with allometric powers (Ht2.0 or Ht2.7) would better define LAE, given the documented consistent strong relationship between Ht and fat free mass. We analyzed 312 cases (mean age 50.3 ± 14.5 years, 35% men) with good imaging quality, sinus rhythm, normal LVEF and no significant valvular disease. Based on body mass index, 5 groups were defined: normal (46), overweight (110) and obese (class I, 81; II, 47; and III, 28). LAV was measured using biplane area-length method and indexed to BSA, Ht, Ht2.0 and Ht2.7. The prevalence of LAE was calculated using the upper limit of 95th percentile of confidence intervals for each LAV parameter. Tissue Doppler E/E’ ratio and cardiovascular (CV) risk factors were obtained. There was no significant difference in gender and age among the groups. CV risk factors were prevalent in overweight and obese groups (47.3%, 60.5%, 59.6% and 82.1%). E/E’ increased across the groups (P < 0.001). LAV indexed by all Ht methods increased significantly (P < 0.001) with a graded increase in prevalence of LAE across the groups. LAV/BSA showed a paradoxical decrease in prevalence of LAE in overweight and obese groups. LAV/BSA significantly underestimated the prevalence of LAE in overweight and obese populations. Ht, either itself or with allometric powers, is the preferred index for LAV measurement.