Reference values for left ventricular dimensions, systolic and diastolic function: a study from the Amazon Basin of Brazil.

Country- and ethnicity-specific reference values for echocardiographic parameters are necessary for decision making. No prior studies have examined reference values in adults from the Amazon Basin of Brazil. We performed echocardiographic examinations in 290 healthy adults (mean age 37 ± 14 years, 40% male) from the Brazilian Amazon. Left ventricular (LV) dimensions and volumes were obtained and indexed to body surface area. We also assessed systolic (LV ejection fraction [LVEF] and global longitudinal strain [GLS]) and diastolic function. LV dimensions and volumes were larger in males compared to females, but after indexation only volumes remained larger (P < 0.001 for all). Parameters of systolic function, were significantly greater in females (LVEF 50 to 68%, GLS - 17 to - 24%) than in males (LVEF 50 to 67%, GLS - 15 to - 23%, P < 0.05). Upper limits of normality for cardiac dimensions (indexed and non-indexed) were markedly higher compared to contemporary guidelines (American Society of Echocardiography) and the Brazilian subgroup in the World Alliance Society of Echocardiography (WASE). Lower limit of normality for LVEF (both sex 50%) and upper limit of normality for the left atrial volume index (LAVI) (male: 31 mL/m2, female: 25 mL/m2) were within normal range but slightly lower compared to guidelines and the WASE study. Other diastolic parameters, including E/A-ratio, E/e' ratio and peak tricuspid regurgitation velocity were compatible with present recommendations. Normal reference ranges of echocardiographic parameters in healthy adults from the Brazilian Amazon Basin may be different compared to international guidelines and data from other regions of Brazil. This applies specifically for LVEF and LAVI.