Left Atrial Size in Hypertensive Men: Influence of Obesity, Race and Age

Objectives. We sought to determine the relations of left atrial (LA) size to blood pressure, obesity, race, age and left ventricular (LV) mass in hypertension. Background. Although obesity, race and age may influence LV mass, their effects on L size have not been defined in hypertension. Methods. Left atrial size was measured in 690 men (58% African-Americans) with mild to moderate hypertension (mean [±SD] blood pressure 152 ± 15/98 ± 6 mm Hg) and high prevalence of LV hypertrophy. Effects of LV mass, adiposity, race, age, physical activity, height, weight, sodium excretion, plasm renin activity and heart rate were examined. Results. Left atrial size was greater (p ≤ 0.0001) in obese (44.2 ± 5.7 mm) than in overweight (41.6 ± 5.9 mm) or normal weight (38.9 ± 6.2 mm) patients. Left atrial enlargement (≥43 mm) was present in 56% of obese patients compared with 42% of overweight and 25% of normal weight hypertensive men. As age increased, white patients had greater L size than African-American patients. Although there was no relation between LV mass and L size in normal weight patients, there was significant positive relation in obese patients. On multiple regression analysis, obesity was the strongest independent predictor of increased L size. Conclusions. Obesity is the strongest predictor of L size in patients with hypertension and amplifies the relation between L size and LV mass. Race influences effects of age and hypertension on L size. Because increased L size and LV mass (also influenced by obesity) are associated with an adverse outcome, these findings underscore the importance of obesity, race and age with regard to the cardiac effects of hypertension.