Ambulatory blood pressure, target organ damage and left atrial size in never-treated essential hypertensive individuals

OBJECTIVE: To investigate the relationship between ambulatory blood pressure and different markers of target organ damage with left atrial size in never-treated essential hypertensive individuals. METHODS: A total of 519 grade 1 and 2 hypertensive patients (mean age 46 +/- 12 years), referred for the first time to our outpatient clinic, underwent routine examinations: 24-h urine collection for microalbuminuria, ambulatory blood pressure monitoring over two 24-h periods in 4 weeks, echocardiography and carotid ultrasonography. RESULTS: Left atrial diameter was increased in 17.3% of patients. No significant differences were found between subjects with and without increased left atrial size with regard to sex, duration of hypertension, clinic and mean 48-h ambulatory blood pressure, and daytime and night-time values. Compared with 429 patients with normal left atrial size, the 90 patients with enlarged left atria were older, had higher body mass index, were more frequently smokers, and included more individuals with the metabolic syndrome. The prevalence of left ventricular hypertrophy, of intima-media thickening, but not of microalbuminuria was significantly higher in subjects with increased left atrial size. CONCLUSION: Left atrial enlargement is not an early echocardiographic finding in relatively young never-treated hypertensive individuals, as its prevalence is lower than that of well-validated markers of target organ damage, and it is unrelated to ambulatory blood pressure. Overweight, left ventricular hypertrophy, carotid intima-media thickening and metabolic syndrome are independent predictors of left atrial dimension, suggesting that changes in left atrial size represent an adaptive response when high blood pressure is associated with other cardiovascular or metabolic abnormalities.