High reclassification rate of height-indexed left atrial volume in obese and overweight patients with cardiac pathologies in daily clinical practice

We sought to investigate the frequency of left atrial (LA) size reclassification in obese and overweight patients with heart disease, adjusting LA volume (LAvol) for height rather than BSA. Obesity is associated with cardiovascular diseases, heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation, among others. Indexing LAvol in obese patients by BSA may misclassify LAvol and the diagnosis of LA dilation. We consecutively studied 253 patients, mean age of 64.3 ± 15.1 years, 146 men (57.7%) with cardiac pathologies. LAvol was measured by the biplane Simpson’s rule. We compared LAvol indexed by BSA, height and height², prevalence and degree of LA dilation among normal weight (< 25 kg/m²), overweight (≥ 25 < 30 kg/m²) and obese (≥ 30 kg/m²) patients. There were 111 (44%) normal weight, 59 (23%) obese and 83 (33%) overweight patients. Overall, the frequency of LA dilation was 58%, 64.2% and 63.8%, indexed by BSA, height and height², respectively. In obese patients these figures were 46%, 65% and 66.6%. Twelve of 30 (40%) obese and 7 of 33 (21%) overweight patients were reclassified from non-dilated to dilated LA when indexed either by height or height². Half (50%) of obese patients were upgraded by one grade, and 37.5% by two grades. Obesity, BMI ≥ 27.5 kg/m² and atrial fibrillation were independent predictors of reclassification. Reclassification of LAvol indexed for height in obese or overweight patients with heart disease is very high. It seems appropriate to use LAvol indexed for height in these patients.